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Springer Series in

materials science 138

Springer Series in

materials scienceEditors: R. Hull C. Jagadish R.M. Osgood, Jr. J. Parisi Z. Wang H. Warlimont

The Springer Series in Materials Science covers the complete spectrum of materials physics,including fundamental principles, physical properties, materials theory and design. Recognizingthe increasing importance of materials science in future device technologies, the book titles in thisseries ref lect the state-of-the-art in understanding and controlling the structure and propertiesof all important classes of materials.

Please view available titles in Springer Series in Materials Scienceon series homepage http://www.springer.com/series/856

With 113 Figures

123

A.D. PomogailoG.I. DzhardimalievaV.N. Kestelman

Macromolecular MetalCarboxylates and TheirNanocomposites

Prof. Dr.Anatolii D. PomogailoRussian Academy of SciencesInst. Problems of Chemical PhysicsAcad. Semenov av. 1142432 ChernogolovkaMoscow region, RussiaEmail: [email protected]

Prof. Dr.Vladimir N. KestelmanKVN International Inc.Jamie Circle 63219406 King of PrussiaPennsylvania, USAEmail: [email protected]

Dr. Gulzhian I. DzhardimalievaRussian Academy of SciencesInst. Problems of Chemical PhysicsAcad. Semenov av. 1142432 ChernogolovkaMoscow region, RussiaEmail: [email protected]

Series Editors:Professor Robert HullUniversity of VirginiaDept. of Materials Science and EngineeringThornton HallCharlottesville,VA 22903-2442, USA

Professor Chennupati JagadishAustralian National UniversityResearch School of Physics and EngineeringJ4-22, Carver BuildingCanberra ACT 0200,Australia

Professor R.M. Osgood, Jr.Microelectronics Science LaboratoryDepartment of Electrical EngineeringColumbia UniversitySeeley W. Mudd BuildingNew York, NY 10027, USA

Professor Jürgen ParisiUniversität Oldenburg, Fachbereich PhysikAbt. Energie- und HalbleiterforschungCarl-von-Ossietzky-Straße 9–1126129 Oldenburg, Germany

Dr. Zhiming WangUniversity of ArkansasDepartment of Physics835 W. Dicknson St.Fayetteville,AR 72701, USA

Professor Hans WarlimontDSL Dresden Material-Innovation GmbHPirnaer Landstr. 17601257 Dresden, Germany

Springer Series in Materials Science ISSN 0933-033XISBN 978-3-642-10573-9 e-ISBN 978-3-642-10574-6DOI 10.1007/978-3-642-10574-6Springer Heidelberg Dordrecht London New York

Library of Congress Control Number: 2010931466

c© Springer-Verlag Berlin Heidelberg 2010This work is subject to copyright. All rights are reserved, whether the whole or part of the materialis concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broad-casting, reproduction on microfilm or in any other way, and storage in data banks. Duplication of thispublication or parts thereof is permitted only under the provisions of the German Copyright Law ofSeptember 9, 1965, in its current version,and permission for use must always be obtained from Springer.Violations are liable to prosecution under the German Copyright Law.The use of general descriptive names, registered names, trademarks, etc. in this publication does notimply, even in the absence of a specific statement, that such names are exempt from the relevantprotective laws and regulations and therefore free for general use.

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Preface

This book is devoted to the single functional group, metal derivatives of unsatu-rated carboxyl ion RCOO�, where R is a radical with multiple bonds. This fieldembraces a huge number of chemical compounds, among which are new typesof monomers and polymers with interesting structures and properties and unusualchemical transformations. This field includes both natural and artificial polymersbut mainly various synthetic materials.

Macromolecular metal carboxylates are currently the object of extensive studiesdue to their unique catalytic, magnetic, optical, and other properties as well as per-spective precursors of novel nanocomposite functional materials. These complexesand nanocomposites have attracted scientific interest both from a fundamental pointof view and their potential applications. Reactivity of unsaturated metal carboxy-lates containing metal atoms in immediate proximity to a polymerizable bond isclosely related to their molecular structure. It is of essence to reveal the peculiar-ities of their behavior, which is determined by the metal on the one side and thepolymeric backbone on the other.

In this book, the main representatives of unsaturated carboxylic and correspond-ing polymeric acids as well as the methods of synthesis of metal carboxylates areanalyzed. There are no analogs of such monographs devoted to various aspects ofsynthesis, polymerization, and properties of the monomeric and macromolecularmetal carboxylates and nanocomposites in the literature.

Structure of monomer and macromolecular metal carboxylates, the type of coor-dination of carboxylate ion, the electronic and valence state of metal, and specificityof metal–organic ligand bond were also considered. We want to note the role ofkinetic and stereochemical effects on the main stages of polymerization and copoly-merization of such metal-containing monomers. Knowledge of these peculiaritiesallows one to effectively control the structure and properties of metallopolymers.

An alternative way to produce of macromolecular metal carboxylates by the in-teraction of polymeric acids with metal compounds is also discussed. In this book,the features of complexation of carboxylic macromolecular ligands, the effects of apolymer chain, the constants of formation and stability of macrocomplexes formedare considered.

Special chapters of the book are devoted to applications of metallopolymer andnanocomposites as well as polymer-assisted synthesis of metal nanoparticles.

v

vi Preface

We think that this book is the first comprehensive analysis of this field of science.We tried to consider the problem as exhaustively as possible, and we hope thatmissed questions are not principal.

Who is our potential reader? Chemistry of carboxylates, as any interdisciplinaryfield of science and technique, rapidly develops, and intensive accumulation of ex-perimental data in this field embarrasses not only beginners but also experiencedresearchers working in this field. First of all, this book can be useful for a widerange of scientists and engineers of research institutes and industry. Then, it canserve as a handbook for students, postgraduate students of universities and collegesthat are interested in this field of science. After 25 years of our own researches inthis field and analysis of literature, we believe in the necessity of appearance of thisbook generalizing accumulated data on all aspects of monomeric and polymericmetal carboxylates.

Section 9.2.1 was written together with Professor Aleksander S. Rosenberg whoto our great regret deceased untimely.

Chernogolovka, Russian Federation Anatolii D. Pomogailo andGulzhian I. Dzhardimalieva

King of Prussia, PA Vladimir N. KestelmanMay 2010

Contents

1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

2 Monomeric and Polymeric Carboxylic Acids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72.1 Mono- and Polybasic Unsaturated Carboxylic

Acids: Characteristic and Polymerization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72.1.1 Monobasic Carboxylic Acids with One Double Bond. . . . . . . . . 72.1.2 Unsaturated Dicarboxylic (Dibasic) Acids . . . . . . . . . . . . . . . . . . . . . 92.1.3 Unsaturated Carboxylic Acids with Triple Bond

(Acetylenic Acids) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102.2 Peculiarity of Polymerization of Unsaturated Carboxylic

Acids and their Polymers Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102.3 Stereoregular Polyacids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172.4 Cross-Linked Polyacids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182.5 Graft- and Block-Copolymers with Carboxyl Fragments. . . . . . . . . . . . . . 192.6 Natural Polyacids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

2.6.1 Polysaccharides. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 222.6.2 Humic Acids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

3 Synthesis of Unsaturated Carboxylic Acid Salts . . . . . . . . . . . . . . . . . . . . . . . . . . 273.1 Reaction of Unsaturated Carboxylic Acids with Metal

Hydroxides, Oxides, and Carbonates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 273.2 Reactions of Acetates and Other Salts with Unsaturated

Carboxylic Acids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 293.3 Ligand Exchange Reactions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

3.3.1 With Metal Halides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 313.3.2 With Metal Alkoxides .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 323.3.3 Other Exchange Reactions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 333.3.4 Synthesis of Bimetallic Compounds . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

3.4 Sol–Gel Reactions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 343.5 Other Reactions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 353.6 Synthesis of Cluster Containing Unsaturated Carboxylates . . . . . . . . . . . 37References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

vii

viii Contents

4 Spectral Characteristics and Molecular Structureof Unsaturated Carboxylic Acid Salts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 574.1 Metal (Meth)acrylates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

4.1.1 IR Spectroscopy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 584.1.2 Magnetic Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 634.1.3 Electron Spectroscopy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 644.1.4 Molecular Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

4.2 Metal Dicarboxylates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 694.2.1 Monomeric Salts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 694.2.2 Coordination Polymers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 744.2.3 Ferromagnetic Properties of Metal Dicarboxylates .. . . . . . . . . . . 83

4.3 -Complexes of Metal Carboxylates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 854.4 Unsaturated �-Oxo Multinuclear Metal Carboxylates .. . . . . . . . . . . . . . . . 88

4.4.1 IR-Spectroscopy .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 894.4.2 Mass-Spectrometry .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 914.4.3 Molecular Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92

4.5 Cluster-Containing Unsaturated Carboxylates . . . . . . . . . . . . . . . . . . . . . . . . . 944.6 Metal Carboxylates with Unsaturated Ligands of Acetylene Type. . . . 96References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .100

5 Polymerization and Copolymerization of Saltsof Unsaturated Carboxylic Acids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1055.1 Types of Initiation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1065.2 Kinetic and Stereochemical Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .109

5.2.1 Radical Polymerization of Alkali and AlkalineEarth Metal Salts of Unsaturated Carboxylic Acids . . . . . . . . . . .109

5.2.2 Radical Polymerization of TransitionMetal (Meth)acrylates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .112

5.2.3 Regulation of Stereochemistry of RadicalPolymerization of Metal Carboxylates . . . . . . . . . . . . . . . . . . . . . . . . .117

5.3 Solid Phase Polymerization of Unsaturated Metal Carboxylates.. . . . .1215.3.1 Thermal Polymerization of Unsaturated Metal

Carboxylates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1225.3.2 Solid State UV and Radiation Initiated Polymerization . . . . . . .1235.3.3 Reactivity of Unsaturated Metal Carboxylates

in Solid Phase. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1255.4 Copolymerization and Terpolymerization .. . . . . . . . . . . . . . . . . . . . . . . . . . . . .128

5.4.1 The Main Principles of Copolymerizationof Alkali and Alkaline Earth Metal Salts . . . . . . . . . . . . . . . . . . . . . . .129

5.4.2 Reactivity of Tin-Containing Carboxylates . . . . . . . . . . . . . . . . . . . .1315.4.3 Copolymerization of Transition Metal Salts . . . . . . . . . . . . . . . . . . .1335.4.4 Kinetic Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1345.4.5 Terpolymerization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .138

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .141

Contents ix

6 Polymer-Analog Transformations in Reactionsof Synthesis of Metal Macrocarboxylates .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1456.1 Complexation of Metal Ions with Macromolecular Ligands . . . . . . . . . .1466.2 Metal Ion Binding by Polyacids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1506.3 Metal Ion Binding by Stereoregular Polyacids . . . . . . . . . . . . . . . . . . . . . . . . .1596.4 Peculiarities of MXn Binding by Cross-Linked Polyacids . . . . . . . . . . . .1616.5 Formation of Macrocomplexes with Grafted

Polycarboxylic Fragments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1626.6 Bimetallic Polycomplexes .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1666.7 Formation of Organic–Inorganic Composites . . . . . . . . . . . . . . . . . . . . . . . . . .1686.8 Binding of MXn by Natural Carboxyl Group Containing

Polymers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .171References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .174

7 Molecular and Structural Organizationof Metal-Containing (Co)Polymers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1797.1 Ionic Aggregations and Multiplets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .179

7.1.1 Ionomers Synthesis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1797.1.2 Morphology and Structure of Ionomers . . . . . . . . . . . . . . . . . . . . . . . .180

7.2 Morphology and Topological Structureof Metal-Containing Polymers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1917.2.1 Three-Dimensional Network Polymers . . . . . . . . . . . . . . . . . . . . . . . .1927.2.2 Interpenetrating Polymer Networks . . . . . . . . . . . . . . . . . . . . . . . . . . . .1947.2.3 Hybrid Supramolecular Structures . . . . . . . . . . . . . . . . . . . . . . . . . . . . .198

7.3 Basic Types of Units Variability in Metal-Containing(Co)Polymers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2057.3.1 Units Variability, Caused by Elimination

of Metallogrouping During Polymerization .. . . . . . . . . . . . . . . . . . .2077.3.2 Units Variability, Caused by Various Oxidation

Rate of d-Metals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2087.3.3 Anomalies in Metal-Containing Polymers

Chains Caused by a Variety of ChemicalLinkage of a Metal with a Polymerized Ligand.. . . . . . . . . . . . . . .209

7.3.4 Extracoordination as One of the Types of Anomalies(Spatial and Electronic Structure of a Polyhedron) .. . . . . . . . . . .210

7.3.5 Unsaturation of Metal-Containing Polymersand Their Structurization.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .211

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .213

8 Properties and Basic Fields of Applicationof Metal-Containing Polymers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2178.1 Improvement of the Polymeric Materials Properties

Based on Cross-Linking Action of Monomericand Polymeric Salts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .217

x Contents

8.2 Radiation Resistance, Photophysical and OpticalProperties of Metal-Containing (Co)Polymers . . . . . . . . . . . . . . . . . . . . . . . . .226

8.3 Water-Absorbing and Sorption Propertiesof Metal-Containing (co)Polymers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .232

8.4 Sorption Properties of Metal-Containing (co)Polymers . . . . . . . . . . . . . . .2388.5 Catalysis by Macromolecular Metal Carboxylates . . . . . . . . . . . . . . . . . . . . .245

8.5.1 Catalytic Reactions of Oxidation of Hydrocarbons .. . . . . . . . . . .2468.5.2 Reactions of Peroxidase Decomposition . . . . . . . . . . . . . . . . . . . . . . .2498.5.3 Other Catalytic Reactions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .251

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .252

9 Monomeric and Polymeric Metal Carboxylatesas Precursors of Nanocomposite Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2579.1 Formation and Stabilization of Nanoparticles

at Presence of Macroligands with Carboxyl Functional Groups . . . . . .2579.2 Basic Obtaining Methods of Metal-Containing

Polymeric Nanocomposites on the Basis of Monomericand Polymeric Carboxylates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2639.2.1 Thermal Conversions of Metal-Containing

Carboxylated Precursors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2639.2.2 Polymer Carboxylate Gels and Block Copolymers

as Reactors for Nanoparticles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2739.2.3 Sol–Gel Methods in the Obtaining of Oxocluster

Hybrid Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2779.2.4 Metal-Containing Polymeric Langmuir–Blodgett Films . . . . . .279

9.3 Metal-Containing Polymeric Nanocomposite Materialsof the Carboxylated Type. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .281

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .284

10 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .289

Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .293

Chapter 1Introduction

At present, there are three main ways of production of metal-containing polymerson the basis of carboxyl precursors [1]: (I) the interaction of metal compoundsMXn with linear functionalized (carboxyl-containing) polymers, when the mainpolymer chain remains untouched (so called polymeranalogous transformations),(II) the polycondensation of proper precursors, when metal ions are incorpo-rated into and removed from the main chain leading to polymer destruction, (III)the recently developed method, polymerization and copolymerization of metal-containing monomers.

I

~ CH2 – CH – CH2 – CH – CH2 – CH~ + MXn

COOH COOH COOH

~ CH2 – CH – CH2 – CH – CH2 – CH~

COOH C O

O

COOH

II

OCOHHCOO

R – L – R

CH2 = CH

C = O

O

initiation

MXn–1

~ CH2 – CH ~

C = O

O

MXn–1

+ MXn–2HX

~ OCOR – L – RCOO – MXn–1~

III

MXn–1

Metallopolymers on the basis of transition metals, obtained by method I, as arule are characterized by low content of bond metal and are used mainly for ion-exchange extraction, concentration, and isolation of metals. Condensation methodII as a rule uses dicarbonic acids, including element – substituted (L), for instancecarboran-containing acids [2, 3]. Production of metallopolymers by method III andinvestigation of their structure and properties is the main content of this book.

Metal carboxylates are widely used in science and technology. They are a partof polynuclear coordination compounds (in catalytic and biomimetic systems) and

A.D. Pomogailo et al., Macromolecular Metal Carboxylates and Their Nanocomposites,Springer Series in Materials Science 138, DOI 10.1007/978-3-642-10574-6 1,c� Springer-Verlag Berlin Heidelberg 2010

1

2 1 Introduction

metal-proteins, intermediate compounds of many metabolic processes. Biochemicalbehavior of metal-enzymes and antibodies is determined in many respects by theircarboxyl ate function [4, 5].

Carboxyl ion can serves as mono-, bi-, and even tridentant ligand of metal ionswith numerous types of coordination. For instance, 18 structural functions of car-boxyl group were found for monobasic carboxylates of transition metals [6] and15 diverse types of coordination were observed by X-ray diffraction study forhomolog of maleate anion C2O4

2� [7].Oxalate ions bind metal ions by only one or two of four oxygen atoms, and

as a rule five-member metallocycles are realized, i.e., potentially tetradentant an-ion C2O4

2� serves usually as bidentant cyclic ligand. In general case, the type ofcoordination depends on a large number of factors: the nature of metal atoms andoutersphere cations, the system of hydrogen bonds, the presence of competing acidicor electroneutral ligands L0. This permits to consider these compounds as so called“smart” materials. This can be illustrated by the following example. It was shownby IR1 and EXAFS that coordination of zinc ion in Zn (II)-neutralized ethulene-methacrylic acid ionomer depends on temperature, the presence of adsorbed water,pressure applied to melt at 130 ıC [9, 10].

In vacuum, Zn(II) carboxylate has mainly a hexacoordinated structure, whichgives IR peaks �as(COO�/ at 1,624 and 1,538 cm�1, but at atmospheric pres-sure (P D 0:1 MPa) a tetracoordinated structure is formed with �as(COO�/ at1,585 cm�1.

Donor–acceptor properties of carbonic acids and their anions in aqueous so-lutions are characterized by the basicity constant pKa. The value of pKa can becalculated quantum-chemically [11]. The energy of decoupling of double bond elec-trons of acrylic acid and its cobalt salt, as well as the ways of formation of thetransition state, differs substantially [12].

In principle, the problem of metal carboxylates can be divided into two unequalparts: the larger and long-developed problem of salts of saturated carbonic acids,and the smaller and recently developed problem of unsaturated carboxylates.Fundamental data on synthesis and properties of saturated carboxylates of metalsand their application are rather well considered in reviews and books, for examplemonograph [13], comprehensive in 1983 and still of current importance, and rathercomplete old and recent reviews [14–17]. Studies of unsaturated carbonic acids are

1 IR spectroscopy is widely used for study of structure of these complexes, because valence vibra-tions iC D O are sensitive to geometry of COO� group and its surrounding [8]. In this groupthe double bond is delocalized and the valence vibration CO splits in asymmetric high-frequency.�as/ and low-frequency symmetric .�s/ vibrations. Intermediate symmetry is possible dependingon the type of coordination (this will be considered in detail in Chap. 4). Other methods of studyof structure of metal-containing group are determination of the values of charges on oxygen atomsof carboxyl and hydroxyl groups and the values of chemical shifts of 13C NMR of carbon of car-boxylate group, estimation of ionization energy (especially for thermochemical calculations), andothers.

1 Introduction 3

practically not generalized. Scrappy data on methods of their synthesis, structure,chemical transformations and numerous applications are dispersed in scientific andpatent literature. Sometimes, analysis of some unsaturated carboxylates can beencountered in reviews and chapters in monographs, but they do not give completepresentation of the state of problem.

At the same time, this type of compounds was intensively studied in last yearsby methods of high-molecular compounds with the aim of obtaining new types ofmetal-containing materials. Although many attempts of generalization of synthe-sis methods and polymerization transformations of some specimens of this type ofmetal-containing monomers are known (see, for example, [18–20]), among themdissertations (for example, [21, 22]), it is enigmatic why unsaturated carboxylateswere not thoroughly analyzed like their saturated analogs.

This task is more difficult because the multiple bond affects all aspects – syntheticand structural chemistry (for instance, in many cases the multiple bond can beinvolved in formation of carboxylate unit), reactivity of these compounds, poly-merization ability. Maybe, this can be explained by interdisciplinary character ofthe problem. On the one hand, synthetic and structural part of carboxylates belongsto inorganic and coordination chemistry where unsaturated ligands are consideredtraditionally as “ugly ducklings”. On the other hand, methods of synthesis and inves-tigation of these promising exotic monomers are rarely developed in high-molecularchemistry. The interests of specialists in these two fields of science are rarely inter-sected in this promising and rapidly developing field of chemistry, therefore one ofthe aims of this book is to draw together these specialists.

Among vast diversity of salts of unsaturated carbonic acids, derivatives of acrylic,methacrylic, crotonic, oleic, fumaric, maleinic, acetyldicarbonic, vinylbenzoic, andsome other acids, which are virtually typical metal-containing monomers contain-ing multiple ready-to-open bonds and metal atoms chemically bond to organic partof the molecule [18]. Unsaturated bond affect coordination of carboxylate ligand.Intensive development of this field in last years is caused by practical value ofobtained products, polymers with ion metals in each chain. This improves manyproperties of polymers and their composites. In subsequent chapters we plan to an-alyze thoroughly transformations of unsaturated metal carboxylates in the course ofsynthesis, as well as their polymerization and copolymerization with conventionalmonomers. Here we only give one example of such transformations. Photopolymer-ization of diacetylene acid (CH3(CH2/11C�C�C�C(CH2/8COOH was studiedin [23] on the interphase air–water in the presence of divalent metal ions Ba (II)(pH 7.7), Cd (II) (pH 6.8), and Pb (II) (pH 6.0). It was found that in the course ofthe photopolymerization carboxylate group of acetylene acid in monolayer in sub-phase of ions Ba (II) and Pb (II) changed its coordination from bridge to bidentant,whereas for Cd (II) the bidentant structure was unchanged at the decrease of molarsquare from 0.8 to 0.18 nm2/molecule, i.e., the polymerization stimulates more com-pact packing of carboxyl groups in monolayers. Experimental data and theoreticalcalculations show that the change of the type of coordination, so called carboxylate

4 1 Introduction

shift, is a low-energy process. This plays an important role in catalytic cycles ofmetal enzymes [24]:

OO

M M

O

O

M M

O OM M

µ−1, 1 µ−1, 2

The carboxyl shift of coordination from bidentant-chelate (��1, 1) to bidentant-bridge (�� 1, 2) is easily observed by 1H � 13C [25] NMR.

Diversity of functions, symmetry of ligands, metal–ligand coordination, varioustypes of bonds in their molecules determine unique possibility for construction ofpromising materials on their basis. Metal oxo-clusters with unsaturated carboxy-late ligands are very promising as nanostructural elements for organic–inorganichybrid nanocomposites [26]. First of all, these are high-organized objects withstrictly determined size and shape which are remained unchanged in final material.Therefore, their distribution in matrix is homogeneous and mono-disperse nanos-tructures are formed. In other words, mono- and polycarboxylates of metals areobjects of supramolecular chemistry, and their polymer films are characterized byimproved mechanical [27, 28], adhesion [29], optical [30], electric [31], and otherproperties.

This book is devoted to a wide range of problems, embracing methods of syn-thesis, structure, and properties of unsaturated metal carboxylates, features of theirpolymerization transformations, morphology, as well as properties and character-istics of formed metallopolymers, including polymeranaloguous transformations.The interest to the problem increased substantially when it was found that thesematerials are effective precursors of metal–polymer nanocomposites [32], in whichcarboxylate matrix or products of its transformation serve as stabilizing agents andprevent aggregation of nanoparticles of metals or their oxides [33].

References

1. D. Wohrle, A.D. Pomogailo, Metal Complexes and Metals in Macromolecules. Synthesis,Structures and Properties (Wiley-VCH, Weinheim, 2003)

2. V.A. Sergeev, N.I. Bekasova, M.A. Surikova, E.A. Baryshnikova, Ya.V. Genin,N.K. Vinogradova, Dokl. Akad. Nauk. 332, 601 (1993)

3. V.A. Sergeev, N.I. Bekasova, M.A. Surikova, E.A. Baryshnikova, N.M. Mishina,T.N. Balykova, Ya.V. Genin, P.V. Petrovskii, Vysokomol. Soedin. A. 38, 1292 (1996)

4. C. He, S.J. Lippard, J. Am. Chem. Soc. 120, 105 (1998)5. W. Ruttinger, G.C. Dismukes, Chem. Rev. 97, 1 (1997)6. M.A. Porai-Koshits, Zh. Strukt. Khim. 21, 146 (1980)7. V.N. Serezhkin, M.Yu. Artem’eva, L.B. Serezhkin, Yu. N. Mikhailov, Zh. Neorg. Khim. 50,

1106 (2005)

References 5

8. K. Nakamoto, Infrared and Raman Spectra of Inorganic and Coordination Compounds,4th edn. (Wiley, New York, 1986)

9. H. Hashimoto, S. Kutsumizu, K. Tsunashima, S. Yano, Macromolecules 34, 1515 (2001)10. S. Kutsumizu, M. Nakamura, S. Yano, Macromolecules 34, 3033 (2001)11. S.Yu. Monakhov, T.A. Stromnova, Zh. Obshch. Khim. 77, 1841 (2007)12. T.S. Zyubina, G.I. Dzhardimalieva, A.D. Pomogailo, in Proceedings of the Russian Conference

‘Present-day state and tendency of development of organometal catalysis’ (IPCP RAS,Chernogolovka, 2009, p.94)

13. R.C. Mehrotra, R. Bohra, Metal Carboxylates (Academic Press, London, 1983), p. 39614. M.A. Porai-Koshits, in Krystallokhimiya (Itogi nauki i tekhniki) [Crystal Chemistry (Advances

in Science and Crystal Ingeneering), vol. 15, ed. by E.A. Gilinskaya (VINITI, Moscow,1981), p. 3

15. G.B. Deacon, R.J. Phillips, Coord. Chem. Rev. 33, 227 (1980)16. A.P. Pisarevskii, L.I. Martynenko, Koordin. Khim. 20, 324 (1994)17. M.A. Kiskin, I.L. Eremenko, Usp. Khim. 75, 627 (2006)18. A.D. Pomogailo, V.S. Savostyanov, Metallcontaining monomers and their polymers (Khimiya,

Moscow, 1988)19. G.I. Dzhardimalieva, A.D. Pomogailo, Russ. Chem. Rev. 77, 259 (2008)20. U. Schubert, Chem. Mater. 13, 3487 (2001)21. R.F. Schlam, Structure and Reactivity of Metal Carboxylates. Thesis Dr. PhD (Brandeis

University, UMI, Ann Arbor, 1998)22. G.I. Dzhardimalieva, (Co)polymerization and thermal transformations as a way for syn-

thesis of metallopolymers and nanocomposites. Doct. Sci. Chem. Thesis (ICPC RAS,Chernogolovka, 2009)

23. G. Ohe, H. Ando, N. Sato, Y. Urai, M. Yamamoto, K.J. Itoh, Phys. Chem. B. 103, 435 (1999)24. D.D. LeCloux, A.M. Barrios, T.J. Mizoguchi, S.J. Lippard, J. Am. Chem. Soc. 120,

9001 (1998)25. A. Demsar, J. Kosmrlj, S. Petricek, J. Am. Chem. Soc. 124, 3951 (2002)26. L. Rozes, N. Steunou, G. Fornasieri, C. Sanchez, Monatsh. Chem. 137, 501 (2006)27. Y.C. Chen, S.X. Zhou, H.H. Yang, J. Appl. Polym. Sci. 995, 1032.(2005)28. M.N. Xiong, S. Zhou, L. Wu, B. Wang, L. Yang, Polymer 45, 8127 (2004)29. T.P. Chou, G.Z. Cao, J. Sol-Gel Sci. Technol. 27, 31 (2003)30. Y.Y. Yu, C.Y. Chen, W.C. Chen, Polymer. 44, 593 (2003)31. C.R. Kagan, D.B. Mitzi, C.D. Dimitrakopoulos, Science 286, 945 (1999)32. A.D. Pomogailo, A.S. Rozenberg, I.E. Uflyand, Metal Nanoparticles in Polymers (Khimiya,

Moscow, 2000)33. A.D. Pomogailo, V.N. Kestelman, Metallopolymer. Nanocomposites (Springer, Berlin,

Heidelberg, New York, 2005)

Chapter 2Monomeric and Polymeric Carboxylic Acids

Our goal was not to analyze known unsaturated carboxylic acids (this problem it-self is unrealizable), but only to give a general idea about unsaturated acids and theirpolymers more often used for obtaining metal carboxylates. Basic attention was paidto those representatives which are a priori capable of polymerization. As data onunsaturated carboxylic acids are dispersed in numerous researches, directories, andcatalogs, many of which are not always accessible, their most important characteris-tics are given below. Other unsaturated heteroacids and their polymers (for example,vinylsulfonic and vinylbenzoic sulfonic acids, thio-, phosphonic, amino-, and otheracids) are not analyzed in this book. More detailed information can be found in otheravailable literature [1–4].

2.1 Mono- and Polybasic Unsaturated CarboxylicAcids: Characteristic and Polymerization

These types of monomers traditionally form the material basis of high-molecularcompounds chemistry. Polycarboxylic acids and polymers based on its derivativesare large-tonnage products. Unsaturated carboxylic acids are used to a great extentfor the preparation of polyethers and polyesters, polynitriles, polyamides, etc.

2.1.1 Monobasic Carboxylic Acids with One Double Bond

The brightest representatives of monobasic unsaturated acids are acrylic andmethacrylic acids (and their derivatives) – the extremely important products inhigh-molecular compounds chemistry. The most widespread commercial synthesesof acrylic acid are oxidative carbonylation of ethylene, vapor-phase oxidation ofpropylene, butylene, and acrolein, hydrolysis of ethylene cyanohydrin, hydrolysis


7

8 2 Monomeric and Polymeric Carboxylic Acids

of “-propiolactone, etc. The basic method for obtaining the acrylic acid is thepreparation from acetylene, carbon oxide, and water:

4 CH�CHC 4H2OC Ni .CO/4 C 2 HCl! 4 CH2DCH�COOHC NiCl2 C H2

(2.1)

The reaction proceeds with a high yield both at standard pressure (in this caseCO is engaged as nickel tetracarbonyl) and at 30 atm and 170ıC with gaseous nickeltetracarbonyl in the presence of catalytic quantities of nickel salts.

Methacrylic acid, CH2DC.CH3/COOH, is obtained by gaseous-phase oxidationof isobutylene, by catalytic gaseous-phase oxidation of methacrolein, and throughan intermediate formation of acetone cyanohydrin, etc.

Many homologs of acrylic acid exist in geometrical stereoisomeric forms causedby a different arrangement of substituents at a double bond, for example, crotonic(trans-) and isocrotonic (cis-) acids, CH3�CHDCHCOOH. Crotonic acid, con-tained in the croton oil, is a crystal substance, b.p. 180ıC and m.p. 72ıC. Isocrotonicacid (b.p. 169ıC, m.p. 72ıC) is a less stable form and it is transformed partly intocrotonic acid by heating up to more than 100ıC.

Angelic (trans-) and tiglic (cis-) acids, CH3CHDC.CH3/COOH, are isomers.The first acid is the labile form (b.p. 185ıC, m.p. 45ıC), the second is the stableform (b.p. 198ıC, m.p. 64:5ıC).

.C/-Cytronellic acid, .CH3/2CDCHCH2CH2CH(CH3/CH2COOH (b.p. 152ıCat 18 mm Hg) is an optical active compound. Undecylenic acid, CH2DCH.CH2/8

COOH, is formed at vacuum distillation of castor oil, b.p. 213ıC at 100 mm Hg,m.p. 24ıC. Ricin acid, CH3(CH2/5CH(OH)CH2CHDCH(CH2/7COOH, is also usedcomparatively often.

Palmitooleic acid, CH3(CH2/7CHDCH(CH2/7COOH, is an oily liquid,b.p. 223ıC at 10 mm Hg, m.p.C14ıC.

Erucic (b.p. 225ıC at 10 mm Hg, m.p. 34ıC) and brassidic (b.p. 256ıC at10 mm Hg, m.p. 65ıC) acids (CH3(CH2/7CHDCH(CH2/11COOH) are geometri-cal isomers.

4-Vinylbenzoic acid has received the most expansion among vinylbenzoic acids.From unlimited number of characterized polyunsaturated fatty acids with two

and three isolated ethylenic bonds in a molecule, used for obtaining the carboxy-lates, the following acids have been used.

Sorbic acid, CH3CHDCHCHDCHCOOH, is synthesized by sorbic aldehydeoxidation prepared by condensation of three molecules of acetic aldehyde. Geranicacid is obtained from 2-methylpentene-2-one-6. ’- and “-Eleostearic acids withthree double bonds (CH3(CH2/3CH2CHDCHCH2CHDCHCH2CHDCH(CH2/4

COOH) are also interesting: ’-isomer is a low-melting form (m.p. 47ıC) and itrearranges into high-melting “-isomer (m.p. 67ıC) at UV-irradiation. Thus, theyare cis–trans-isomers having especially high abilities to “exsiccation” as well as allacids with three ethylenic bonds.

Linolenic acid, CH3(CH2CHDCH)3(CH2/7CO2H, is also one of the “exs-iccant” fatty acids (b.p. 229ıC at 16 mm Hg and 184ıC at 4 mm Hg, density0.905 g/cm3 .20ıC/, it is quickly oxidized and solidified in air). Linolenic acid and

2.1 Mono- and Polybasic Unsaturated Carboxylic Acids: Characteristic and Polymerization 9

many unsaturated arachidonic acids are the vital fatty acids. Dehydrogeranic acid,(CH3/2CDCHCHDCHC(CH3/2DCOOH, (m.p. 185–186ıC) also should be noted.

2.1.2 Unsaturated Dicarboxylic (Dibasic) Acids

Unsaturated dicarboxylic acids can be mono- or polyunsaturated. The most impor-tant representatives of “-dicarboxylic acids are the first members of this row, maleic(m.p. 130ıC) and fumaric (m.p. 287ıC) acids, HOOC�CHDCH�COOH, differedby a spatial structure. Maleic acid has cis- and fumaric acid has trans-configuration.Both acids are obtained by heating of malic acid but at different temperatures.In industry, maleic acid (as maleic anhydride) is prepared under catalytic oxidationof benzene by the oxygen in the air.

When two electron-seeking carbonyl groups are conjugated with an olefinic sys-tem, acceptor character of CDC bond especially increases. Maleic anhydride has thebest acceptor properties among derivatives of ’, “-unsaturated dicarboxylic acids.Maleic acid is stronger than fumaric acid: hydrogen atom of the first carboxyl groupdissociates more easily, than in case of fumaric acid, and conversely for the secondcarboxyl group. Ionization constants at 18ıC are:

– For maleic acid pK1 D 2:0, pK2 D 6:23

– For fumaric acid pK1 D 3:03, pK2 D 4:38

For comparison we shall note that for oxalic acid (saturated analog of maleic andfumaric acids), pK1 D 1:46 and pK2 D 4:40.

Citraconic, methylmaleic (m.p. 91ıC), mesaconic, and methylfumaric (m.p.202ıC) acids have the same relationship among themselves as well as with maleicand fumaric acids: the first of them is a cis-form, second is a trans-form.

(1) (2) (3)

HO2CCHHCCO2HCH2CO2H

CH2=CCO2H CH3CCO2HCH3CCO2H

Itaconic, 2-methysuccinic (1), acid and their isomers, citraconic (2) and mesaconic(3) acids, are more often than other acids used for the binding of metal ions as wellas their polymeric analogs. Besides, itaconic acid is the perspective candidate forobtaining the high-functionalizated copolymers. It is connected with the low costof itaconic acid received from renewable sources under fermentation by Aspergillusterrus microorganisms.

Unsaturated tribasic propene-1,2,3-threecarboxylic (aconitic) acid, HOOC�CH2�C.COOH/DCH�COOH, is obtained by water elimination from citric acid.It is rather distributed in flora and contained in sugar-cane and beet; it is extractedfrom Aconitum poisonous plants of the buttercup family. Unfortunately, these acidshave not yet found practical application in the metal carboxylates synthesis.


2.1.3 Unsaturated Carboxylic Acids with Triple Bond(Acetylenic Acids)

Interaction of sodium derivatives of acetylenic hydrocarbons with carbon dioxidefacilitates the preparation of acetylenecarboxylic acids in which triple bond is local-ized near a carboxyl group as depicted in the following scheme:

CnH2nC1C�CNaC CO2 ! CnH2nC1C�CCOONa (2.2)

This type of acids has received the name of propiolic acid series because ofthe simplest representative of this series, propiolic acid, HC�CCOOH. Propiolicacid is a liquid with a pungent smell (b.p. 83ıC at 50 mm Hg, m.p. 9ıC). Thepeculiarity of propiolic acid (as will be shown in the subsequent chapters) givesthe possibility of the replacement of hydrogen atom by metal not only in the car-boxyl group but also in the acetylenic residue. Methyl-propiolic (CH3C�CCOOH,b.p. 203ıC), 2-octynoic acid (CH3(CH2/4C�CCOOH), and phenyl-propiolic((C6H5/C�CCOOH) acids are the most commonly used for the preparation ofcorresponding carboxylates among numerous higher homologs of propiolic acid.

Carboxylic acids in which triple bond is far from the carboxyl groupcan be synthesized from the corresponding dibromodirevatives of fatty acidsby hydrogen bromide elimination upon alkali, for example, stearolic acid,CH3(CH2/7C�C(CH2/7COOH, and its isomer – 6-octadecynoic acid, CH3(CH2/10

C�C(CH2/4COOH. A set of strongly unsaturated acids containing acetylenic andethylenic bonds was extracted from plants and prepared synthetically.

Derivatives of acetylenedicarboxylic acids are less important for the problemunder consideration, although 10,12-penta-cosadiynoic acid (CH3(CH2/11C�C�C�C(CH2/8COOH) forms Langmuir–Blodgett films easily [5].

Some properties of unsaturated carboxylic acids considered are summarized inTable 2.1.

The composition and structure of unsaturated carboxylic acids determine the ba-sic approaches to their carboxylates, on the one hand, and to their polymerization,on the other hand.

2.2 Peculiarity of Polymerization of Unsaturated CarboxylicAcids and their Polymers Structure

Unsaturated carboxylic acids can be classified as polymerized (most often by theradical mechanism) ionized monomers as well [8]. In turn, obtained linear water-soluble polymers are ionomers – ion-containing polymers with a carbon-containingmain chain and relatively small number of partly or completely ionized acidicgroups of carboxylic, sulfonic, phosphoric, and other acids in a side chain [9–11].

2.2 Polymerization of Unsaturated Carboxylic Acids and their Polymers Structure 11

Tab

le2.

1C

ompo

sitio

nan

dch

arac

teri

stic

sof

unsa

tura

ted

carb

oxyl

icac

ids

Aci

dFo

rmul

aB

.p.(

ıC

/mm

Hga )

M.p

..ı

C/

pKa

.ıC

/d

420

(g/m

L)

nD

20

Mon

obas

icun

satu

rate

dca

rbox

ylic

acid

sA

cryl

icac

idC

H2DC

HC

OO

H13

9;14

2/76

013

4.25

(25)

1.05

1;1.

045

.25

ıC

/1.

4242

;1.4

185

Met

hacr

ylic

(2-m

ethy

lpro

pion

ic)

acid

H2C

DC(C

H3/C

OO

H16

312

–16

4.66

1.01

51.

431;

1.42

88

Cro

toni

c(t

rans

-2-b

uten

oic)

)ac

id

CH

3C

HDC

HC

OO

H18

5(76

0)180–1

81

ıC

71.5

.70–7

2ı

C/

4.69

(25)

1.02

7.2

5ı

C/

2-E

thyl

acry

lic

acid

H2C

DC(C

2H

5/C

O2H

176

0.98

6.2

5ı

C/

1.43

72-

Pent

enic

(tra

ns-2

pent

enic

)ac

idC

2H

5C

HDC

HC

O2H

106

ıC

/20

9–11

0.99

.25

ıC

/1.

452

4-Pe

nten

ic(3

-vin

ylpr

opio

nic,

ally

lace

tic)

acid

CH

2DC

HC

H2C

H2C

OO

H83

–84/

12�2

2:5

0.98

1.2

5ı

C/

1.42

8

2-Pr

opyl

acry

lic

acid

CH

3(C

H2/ 2

(DC

H2/C

O2H

165–

188

0.95

1.2

5ı

C/

1.44

12-

Oct

enoi

cac

idC

H3(C

H2/ 4

CH

DCH

CO

2H

154/

225–

60.

944

.25

ıC

/1.

4588

3-V

inyl

benz

oic

acid

H2C

DCH

C6H

4C

O2H

91–9

54-

Vin

ylbe

nzoi

c(s

tyre

ne-4

-car

boxy

lic)

acid

H2C

DCH

C6H

4C

O2H

142–

144

2-C

arbo

xyet

hyl-

acry

late

CH

2DC

HC

O2.C

H2/ 2

CO

2H

103

ıC

/19

mm

Hg

1.21

4.2

5ı

C/

tran

s-3-

Ben

zoyl

acry

lic

(4-o

xo-4

-phe

nyl-

2-bu

teno

ic)

acid

C6H

5C

OC

HDC

HC

O2H

94–9

7

2-B

rom

oacr

ylic

acid

H2C

DC(B

r)C

O2H

62–6

5ı

2-B

rom

omet

hyl-

acry

lic

acid

CH

2DC

.CH

2B

r/C

OO

H70–7

3ı

(con

tinu

ed)


Tab

le2.

1(c

onti

nued

)

Aci

dFo

rmul

aB

.p.(

ıC

/mm

Hga )

M.p

..ı

C/

pKa

.ıC

/d

420

(g/m

L)

nD

20

Ric

inol

eic

acid

,(R

)-12

-hyd

roxy

-cis

-9-

octa

dece

noic

,12

-hyd

roxy

l-ol

eini

cac

id

CH

3(C

H2/ 5

CH

(OH

)CH

2

CH

DCH

(CH

2/ 7

CO

OH

0.94

0

10-U

ndec

enoi

cac

idC

H2DC

H.C

H2/ 8

CO

OH

137/

223

–25

0.91

2.2

5ı

C/

1.44

9ci

s-5-

Dod

ecen

oic

acid

CH

3(C

H2/ 5

CH

DCH

(CH

2/ 3

CO

2H

135/

0.4

0.90

6.2

5ı

C/

1.45

4Pa

lmit

olei

nic

(cis

-9-h

exad

ecen

oic)

acid

CH

3(C

H2/ 5

CH

DCH

(CH

2/ 7

CO

OH

162/

0.6

0.5

0.89

51.

457

tran

s-O

lein

ic(t

rans

-9-o

ctad

ecen

oic,

tran

s-E

laid

ic)

acid

CH

3(C

H2/ 7

CH

DCH

(CH

2/ 7

CO

OH

288/

100

42–4

4

cis-

Ole

inic

(cis

-9-o

ctad

ecen

oic,

elan

oic)

acid

CH

3(C

H2/ 7

CH

DCH

(CH

2/ 7

CO

OH

194–

195/

1.2

13–1

40.

887

.25

ıC

/1.

459

cis-

11-E

icos

enoi

c(g

ondo

ic)

acid

CH

3(C

H2/ 7

CH

DCH

(CH

2/ 9

CO

2H

23–2

40.

883

.25

ıC

/1.

4606

Ner

voni

c(c

is-1

5-Te

tra-

cose

noic

)ac

id

CH

3(C

H2/ 7

CH

DCH

(CH

2/ 1

3C

OO

H42

–43

’-L

inol

eic

(cis

,cis

,ci

s-9,

12,1

5-O

ctad

ecat

rien

oic

acid

CH

3(C

H2C

HDC

H) 3

(CH

2/ 7

CO

2H

230–

232/

1�1

10.

914

.25

ıC

/1.

480

(con

tinu

ed)


Tab

le2.

1(c

onti

nued

)

Aci

dFo

rmul

aB

.p.(

ıC

/mm

Hga )

M.p

..ı

C/

pKa

.ıC

/d

420

(g/m

L)

nD

20

”-L

inol

enic

acid

(cis

,cis

,ci

s-6,

9,12

-O

ctad

ecat

rien

oic)

acid

CH

3(C

H2/ 3

CH

2C

HDC

HC

H2

CH

DCH

CH

2C

HDC

H(C

H2/ 4

CO

OH

cis-

5,8,

11,1

4,17

-E

icos

apen

ta-e

noic

acid

CH

3(C

H2C

HDC

H) 5

(CH

2/ 3

CO

2H

�54

�53

0.94

3.2

5ı

C/

1.49

77

Ace

tyle

nic

carb

oxyl

icac

ids

Prop

ynoi

c(A

cety

lene

carb

o-xy

lic,

Prop

inoi

c)ac

id

HC

�CC

OO

H14

4/76

0;83

/50;

102/

200

18;9

,16–

181.

84(2

5)1.

138

.25

ıC

/1.

431

2-B

utyn

oic

(tet

roli

c,1-

Prop

ynec

arbo

xyli

c,3-

Met

hyl-

prop

ioli

c)ac

id

CH

3C

�CC

O2H

203/

760

78–8

02.

50

2-Pe

ntyn

oic

acid

CH

3C

H2C

�CC

O2H

47–5

34-

Pent

ynoi

c(P

ropa

rgyl

acet

ic)

acid

[6,7

]

CH

�CC

H2C

H2C

OO

H11

0/30

54–5

7

2-H

exyn

oic

acid

CH

3(C

H2/ 2

C�C

CO

2H

230

0.99

2.2

5ı

C/

1.46

02-

octy

noic

(2-O

ctyn

-1-o

ic)

acid

CH

3(C

H2/ 4

C�C

CO

2H

148–

149/

192–

50.

961

.25

ıC

/1.

46

Phen

ylpr

opyn

oic

acid

C6H

5C

�CC

OO

H13

5–13

713

72.

23(2

5)(c

onti

nued

)


Tab

le2.

1(c

onti

nued

)

Aci

dFo

rmul

aB

.p.(

ıC

/mm

Hga )

M.p

..ı

C/

pKa

.ıC

/d

420

(g/m

L)

nD

20

Uns

atur

ated

dica

rbox

ylic

acid

sFu

mar

ic(t

rans

-1,2

-E

then

e-di

carb

oxyl

icac

id

HO

OC

CH

DCH

CO

OH

298–3

00

ıC

(cy b

l)16

59cy

bl.)

/1.7

3.02

,4.3

8

Mal

eic

(2-B

uten

edio

ic,

cis-

1,2-

Eth

ylen

e-di

carb

oxyl

ic,

Toxi

lic)

acid

HO

OC

CH

DCH

CO

2H

137–

140

1.92

,6.2

31.

59.2

5ı

C/

Itac

onic

(2-p

rope

ne-1

,2-

dica

rbox

ylic

;Suc

cini

cac

id,m

ethy

lene

-)ac

id

HO

2C

CH

2C

(DC

H2/C

O2H

165–

168

3.85

,5.4

51.

573

.25

ıC

/

cis,

cis-

Muc

onic

(cis

,cis

-2,

4-2,

4-H

exad

iene

dioi

c)ac

id

HO

OC

�CH

DCH

�CH

DCH

�CO

OH

194–

195

Ace

tyle

ndic

arbo

xyli

c(2

-But

yned

ioic

)ac

idH

OO

CC

�CC

OO

H18

0–18

7(p

a zl.

)

2-A

ceta

mid

o-ac

ryli

cac

id;

Ace

tyl-

dehy

droa

lani

neC

H2DC

.NH

CO

CH

3/C

OO

H18

5–18

6(p

azl.

)

Mal

eic

acid

mon

oam

ide

(mal

eam

ic)

acid

H2N

CO

CH

DCH

CO

2H

158–

161

a 1m

mH

gD

133.

322

n/m

2


Among carboxylic acids, polyacrylic (PAA) and polymethacrylic (PMAA) acidshave found an application as macroligands for the binding of the metal ions. PAA isa weak polymeric acid and it is similar to the polybasic saturated acids in its chemi-cal properties. The average value of pKa in aqua solutions (concentration 0.1 mol/L,alkali titration, 25ıC) is equal to 6.4.

Polyacids are obtained usually in water solutions in the presence of potas-sium, sodium, or ammonium persulfate or by initiating systems of “ammoniumpersulfate – ascorbic acid” type – and also under the action of metal chelates.M �� 50; 000/ [12]. As a rule, these monomers exist in a form of cyclic or lineardimers, in which double bonds are considerably removed from each other.

CH2 CH2 CH2 CH2

CH3

CH3

CH3

CH3

C C

O

OHCC

O

HO

C C

O

OHCC

O

HO

PAA, synthesized in the presence of peroxide initiators, is characterized by branch-ing and rather low molecular weights; the reason is the reactions of chain transferto a monomer or to a polymer due to hydrogen atoms of CH2 group. Thus, the ratioof the growth rates to the termination rates of polymer chains upon bulk polymer-ization of methacrylic acid .44:1ıC/, initiated by azobis(isobutyronitrile), is equalto kp=kt

0:5 D 0:278; �H D 13:5 kcal=mol. [1]Kinetics of free-radical polymerization of the nonionized methacrylic acid in

water solutions has a lot of peculiarities (see, for example [13]).Unsaturated carboxylic acids can enter into the polymerization reaction both in

protonic (below pKa/ and in deprotonic (anionic) (over pKa/ forms:

RCOOHpKa��! RCOO� C HC (2.3)

Deprotonation results in the appearance of electrolytic repulsion between polymer-ized groups. It depends on many factors, the main of which are solvent nature, pH,and an ionic strength of a solution. They determine also molecular-mass (MM) char-acteristics of the polymers formed [14, 15]. Concentration of the ionized carboxylgroups [COO�] is ˛c, where ˛ is the average dissociation degree, cis the totalconcentration of carboxyl groups. The curve of the potentiometric titration of thepolymeric acids is described by the Henderson-Hasselbach equation:

pH D pK 0a �m lg Œ˛=.1 � ˛/� ; (2.4)

where pK 0a is the characteristic constant, equal to pH value at ˛D 0:5; m is the

empirical parameter considering influence of electrostatic effect – deviation of sys-tem behavior from the law for low molecular weight analogs (for polyelectrolytesm > 1, whereas for monomeric electrolytes mD 1). The ratio of the ionization con-stant of a polymeric acid to the ionization constant of an analogous monocarboxylicacid is approximately equal to 10�4. It is important that the acidity of the carboxyl


group having two nonionized acidic groups in the neighborhood should be morethan the acidity of the carboxyl group with one or two ionized carboxyl groups; theneighboring groups should not be necessarily the same type. It is illustrated by thistypical example. Carboxyl group and phenolic fragment influence mutually on theiracidic properties because of the intramolecular hydrogen bond formation. It is veryimportant under the action of ribonuclease [16]. Values of pK 0

a and m of polyacidsdepend on the ionic composition of the solution. Thus, pK 0

a of carboxyl groups inpolymeric acids can be approached to pK 0

a of their monomeric analogs with an in-crease in the ionic strength of the solution; pK 0

a and mcan change from 6.17 to 4.60and from 2.0 to 1.44 [17]. In other words, PAA is a weak polyelectrolyte and pHincreasing induces the rise of the number of negative charges. Besides, pK 0

a valueis essentially influenced by the neighboring groups and by the cross-linking degreeof polymer chains, degree of a coil convolution. Characteristic viscosity Œ�� of theionized acids is higher than that Œ�� of the initial acids because of the electrostaticrepulsion between ionized groups and extension of polymer chains. It confirms therod-like form of the short chains of the ionized PAA in water. The chain length andthe solvent nature determine the solution concentration at which polymeric coilsstart to interact. Polymeric coils can be considered as relatively isolated in a goodsolvent of 1–2 mass% concentration and at the molecular mass of PAA �100,000.PAA macromolecule is unfolded in water to a greater extent than in the organic™-solvent (dioxane). Its hardness is characterized by the value of Kuhn segmentequal to 17 A and can be compared with the flexibility of the noncharged poly-mers. Hydration numbers are equal to 4.9–5.4 at 25ıC and 5.6–6.0 at 35ıC perone PAA unit.

PMAA is the nearest chemical analog of PAA but it has a series of anomalousproperties in aqueous and alcoholic solutions which are given below. The first prop-erty is the more compressed and compact structure stabilized by hydrogen bondswhich results in the formation of the cyclic secondary structures. The second oneis the hydrophobic interactions of methyl groups (at ˛ < 0:15). Hydrophobic areasstick together aspiring to avoid contacts with water (like surface-active substances(SAS) which consist of polar and nonpolar groups and form micelles at dissolutionin water. Nonpolar groups in the micelles are turned inside). Besides, replacementof CH3 : : : CH3 to H3C : : : H2O contacts induces additional structuring of water, de-creasing the solvent entropy and exceeding the entropy increase of macromoleculesat their structure destruction. Addition of organic solvents or ionization induces thecooperative polymer unfolding, and methanol forms the intramolecular hydrogenbonds worse than water. It is also necessary to take into account that PMAA itselfshows pH-induced transfers especially in the diluted aqueous solutions at pH equalto 4–6 [18].

The contact structures formed in polyethylacrylic acid molecules are morestable than PMAA structures. It is seen from the comparison of free energyof their conformational transfer (�F D 0 for PAA, �F D 150 for PMAA and�F D 1; 000 cal/mol for PEAA) [19]. Polymonomethylitaconate behaves similarlyto PMAA.

2.3 Stereoregular Polyacids 17

Among other polyacids, we shall note poly-4-carboxystyrene, prepared bypolymerization and more often by copolymerization of 4-vinylbenzoic acid andpolymaleic acid and polymers based on polymaleic anhydride. These polyacids canalso be obtained by polymeranalogous reactions. Formation of the copolymer ofmaleic acid and vinyl alcohol under copolymerization of maleic acid with vinylbutylester at 60ıC followed by hydrolysis of the precipitate formed [20] can be given asan example. Copolymerization of unsaturated carboxylic acids is also characterizedby a lot of peculiarities. Without going into details we shall note only that kp=k0:5

tvalue decreases, as a rule, with an increase in their concentration in a monomericmixture (by the example of copolymerization of styrene with itaconic acid [21]).

Lastly, we shall note that many representatives of carboxyl containing polymersare the so-called “smart” polymers having such a feature as the temperature influ-ence on the chains conformation [22]. Thus, the ability of the linear macromoleculesof a heat-sensitive poly(N -vinylcaprolactam-co-methacrylic acid) to swell is thefunction of pH and temperature of a solution and MAA unit’s quantity [23].

2-Carboxybenzoyl- and 3-carboxyl-2-naphthoyl-substituted derivatives of styreneand 4-vinylbenzoyl-20-benzoate [24] are able to form polychelate complexes due toO,O-functional knots.

CH2 CH CH2 CH

C O

C

O

OH

n m

The number of such examples can be increased essentially without doubt.

2.3 Stereoregular Polyacids

Stereoregular polyacids, especially PAA and PMAA, are the most interestingmacroligands. Isotactic PAA is obtained by hydrolysis of polyisopropenylacrylatewhich, in its turn, is synthesized at�78ıC with use of BrMgC6H5 as a catalyst [25].Isotactic PMAA is prepared by methods of polymeranalogous reactions such as hy-drolysis of isotactic PMMA (it is the methyl methacrylate polymerization initiatedby ethylmagnesiumbromide). Isotacticity degree of this polymer is approximatelyequal to 90% and molecular weight is equal to 4.8 � 104 [26]. Radiation polymer-ization of acrylic acid (initiated by ”-irridation of 60Co at �78ıC in polar solvents)gives syndiotactic PAA as a product [27]. Another approach is the transformation ofsyndiotactic anhydride of PAA, obtained by cyclopolymerization, into syndiotactic


PAA. After that syndiotactic PAA is transformed into isotactic polyanhydride (atheating with Py) and into isotactic PAA [28].

The isotactic polyelectrolyte has a local spiral conformation (degree of helicityis equal to 0.72) because of strong electrostatic repulsion between the fixed charges,while atactic and syndiotactic chains have a flat zigzag conformation. Flexibilityof PAA depends on tacticity and nature of a solvent and is in the following order:isotactic > atactic > syndiotactic (in organic mediums) and syndio- > iso > atactic(in water).

Iso-PMAA also has a local spiral conformation, and syndio-PMAA has a flatzigzag conformation. The flat zigzag conformation is favorable for the formationof contacts between hydrophobic methyl groups that realized in the nonionizedmolecules of PMAA in water; formation of CDO: : :.H�O hydrogen bonds betweenthe neighboring monomer units are preferable in the organic solvents. Stereoregu-lar structures influence essentially on the nature of the conformational transfer fromcompact globules to more unfolded solvated chains [29]. Addition of the organicsolvents containing nonpolar groups weakens the interaction of methyl groups andpromotes the transfer of a macromolecule into more unfolded conformation. It willbe shown in the subsequent chapters that stereostructure of polyacids influencesessentially on their ability to carboxylate formation.

2.4 Cross-Linked Polyacids

Cross-linked polyacids have been produced by the industry of ion-exchangeresins for several decades. Usual subacid cation-exchange resins include groupsof aliphatic carboxylic acids and contain �3.5–5 mg-eqv of an acid per 1 g of amaterial.

Cationites consisting of the cross-linked PMAA, obtained directly under sus-pension copolymerization of MMA with a mixture of divinylbenzenes, contain ahigh number of carboxyl groups (9–10 mg-eqv/g) that correspond to the polymerin which almost 100% of side groups are acidic. The comprehensive description ofsuch synthesis for obtaining the ion-exchange resins is given in numerous guides.

Most often, ion exchangers are converted into necessary forms: deprotonated.˛ ! 0/, completely protonated .˛ ! 1/ and partly protonated .1 > ˛ > 0/. Forobtaining a deprotonated form, an ion exchanger is treated with 5% aqueous solu-tion of NaOH. A protonated form is prepared under washing out an ion exchangerwith a solution of 1 N HNO3. A partly protonated ion exchanger is formed underthe treatment of the protonated and deprotonated forms by the calculated quantityof an alkali or an acid. The most typical examples are saponified copolymer ofmethylmethacrylate and divinyl benzene and aminated dimethyl ester of iminodi-acetic acid and chloromethylated styrene copolymer with divinyl benzene; the otherion exchanger is obtained under condensation of pyridine, polyethylenepolyamine,and epichlorohydrin, modified by a chloracetic acid.

2.5 Graft- and Block-Copolymers with Carboxyl Fragments 19

Micronetwork polymers are divided into microporous (pores size less than 2 nm),mezoporous (pores size is 2–5 nm) and macroporous (pores size more than 5 nm).These polymers provide more successful isolation of carboxyl groups than gelpolymers under the same conditions. However, micronetwork polymers also havesome drawbacks. For example, concentration of carboxyl groups approx. equal to1 mmol/L can be considered as the limiting concentration. At the concentration ofcarboxyl groups, more than 1 mmol/L effects of intrapolar interaction are revealed,and significant amount of anhydride cycles is formed. The nature of these parti-cles and also their pores elasticity allow them to be used both in gaseous- andliquid-phase reactions in aqueous and in nonaqueous mediums, maximal operatingtemperature for subacid resins being about 125ıC.

Significant attention to this class of polymers is given in literature (see, for ex-ample, monography [30]) because of wide spread and systematical researches ofcarboxylic cation exchangers (the saponified copolymer of methylmethacrylate anddivinyl benzene type) and ampholytes.

2.5 Graft- and Block-Copolymers with Carboxyl Fragments

Copolymers on the basis of graft and block-copolymers satisfy the basicrequirements for designing the macroligands of the new type with polymer-bearingfunctional groups. And though these types of copolymers are used for obtainingcomposite materials with the improved physicochemical properties and impartingnew properties to the modified polymers [31, 32], such “bilayer” materials withcarboxyl groups appeared to be an interesting object for the formation of the macro-molecular metallocomplexes – metal carboxylates. Graft- and block-copolymersare macroligands and their properties are determined in many respects by the typeof a polymer-substrate, by the quantity and length of a graft carboxyl fragment,and by the character of their distribution in a material: whether they localize onlyon a polymer-substrate surface forming an external covering, form a layer withsome diffusive extension into the depth of a polymer to which they are grafted, ordistribute evenly in the whole volume of the polymer (Fig. 2.1).

The general scheme of obtaining such carboxylcontaining macroligands in areductive view can be shown as follows [33, 34]. The polymer to which carboxy-lated fragments are grafted (most often, PE, PP, CEP, PVC, PTFE, PS, cellulose,etc.) is subjected to mechanical, chemical (induced initiation, ozonolysis, oxidation-reduction systems, etc.), and radiochemical (”-irradiation of 60Co; acceleratedelectrons; low-temperature gas-discharge plasma of low pressure; plasma of glowlow-, high-, and ultrahigh-discharge; corona discharge; UV-irradiation, etc.) initia-tion in the presence of a grafted acid (or by the post-effect). Such initiation resultsin the formation of active centers (free radicals, ion-radicals, ions on which graftpolymerization takes place) on the surface or in the near-surface layer of the initialpolymer. Graft polymerization of unsaturated acids can be homophase (graft is in asolution of polymers) or heterophase (suspension or gaseous-phase). The last typeof processes can be presented by Scheme 2.1.


L L

a b c

d e f

LL L

L

LL

L

L L

LLLLL

L

L

50 nm

L

L

LLL

L L LL

L

LL

L

L

L

L

50-80 mm

L

L

L L

LL

L

200 mm

L

LL

L LL

L

L

L

LL

L

L

L

L

L

L

L

L L

L

L

LLL

L

L

100 mm

LL L

LL

LL

L

L

LLL

L

LLL

LL

L

L

LL L

LL

L

L

LL

L L L

L

LL

L

LL L

L LLL

LL

LL LL

LL

LLL L L

L

LL

Fig. 2.1 Schematic diagram of the distribution of functional groups in polymers of various types.The type of polymer: (a) a linearic or branched polymer, (b) a slightly cross-linked (swelled)polymer, (c) a highly cross-linked polymer (macroporous) polymer, (d) a polymer with a graftedfunctional layer, (e) a polymer with microencapsulated particles, (f) the material of hybrid type

Initiation

Polymer surface

m(CH2 = CH)

(CH2 – CH-)mCOOH

COOH

Scheme 2.1 Graft polymerization of unsaturated acids on the surface of polymer

The most effective technique of graft polymerization of unsaturated acids is thegaseous-phase graft polymerization of acrylic and methacrylic acids on the surfaceof HDPE under plasmochemical treatment. For example, formation of a monolayerfrom carboxyl groups on a polymer-powder surface (Ssp D 10 m2/g) is equivalent toa graft of 1% mass of acrylic acid. As a rule, thickness of a grafted layer does not ex-ceed 10–30 nm. For acrylic or methacrylic acids graft polymerization on the surfaceof HDPE not only penetrating radiation, but also low-temperature HF-gas-dischargeplasma can be used (Fig. 2.2) A contribution to the total action of such plasma isintroduced by electrons, ions, radicals, excited particles, and electromagnetic radi-ation; elementary act of monomer insertion into polymer structure is catalyzed byelectron-ion bombardment of this surface (Table 2.2) [35].

2.5 Graft- and Block-Copolymers with Carboxyl Fragments 21

Fig. 2.2 Scheme of the setupfor high frequency grafting ofmonomers into a surface ofpolymer (powder): 1 –reservoir for polymer(powder), 2 – vacuum seal,3 – quartz discharge tube,4 – high frequency generator,5 – reactor with stirring,6 – reservoir for a graftingmonomer

1

2

3

4

5

6Vacuum

Table 2.2 Graft polymerization of acrylic and methacrylic acids onHDPE initiated by high frequency dischargea

Degree of graftingPolymer substrate Grafting monomer wt% 104 mol/g

PE CH2DCHCOOH 2:0 2:8

PE The same 9:1 12:6


PE CH2DC.CH3/COOH 2:7 3:7

PE The same 7:0 9:7


PEb CH2DCHCH2OH 2:0: 2:76

aPower 1 W/cm3, residence time in discharge is 1 s, the temperaturefor monomer and substrate 20ıCbTo compare the data of grafting of allylic alcohol are given

From the peculiarities of gaseous-phase graft polymerization of AA and MAAto a powdered HDPE, we shall note high values of radiochemical yield under initi-ation by ”-irradiation (G�M more than 2,000 molecules/100 eV of absorbed energyat 20ıC) and also high effectiveness of high frequency grafting (Table 2.2): achieve-ment of 5–10 mass% is not difficult experimentally because of sufficiently highvapor pressure of these monomers at graft temperature. A characteristic feature ofgraft polymerization of AA on the oriented PE-films is a formation of stereoregu-lar (isotactic) structures in graft fragments [36]. As the thickness of a graft layerincreases, ordering in a graft PAA connected with oriented character of monomericmolecules in adsorbed layer, has become apparently worse. The most importantfactors determining stereoregularity of graft copolymers is the structure of thoseareas on which graft occurs: pore size, supramolecular structure, etc. By an exam-ple of gaseous-phase graft copolymerization of vinylidene chloride and acrylic acidgrafted on stretched polyamide fibers of nylon-66, the opportunity of the matrix syn-thesis of macromolecules with monomers distribution specified by a substrate wasfound [37]. The effect of matrix copolymerization is caused by a selective sorptionof acrylic acid molecules on peptide groups of a fiber. It results in the formation


of a sorption layer on a polymer-substrate; composition of this layer reflects analternation of structural elements of polymer-substrate. This order also remains inmacromolecules of a copolymer forming in the sorption layer. In case of a graft ofacrylic acid to a powdered HDPE, stereoregular structures were not revealed [38].

Graft polymers are copolymers with the peculiarity in a reactive groups’ loca-tion; almost all reactive groups are on the surface and are accessible for the reagents(including metal salts) at suspension technique of binding together. By a graft ofacrylic and methacrylic acids ion-exchange membranes are obtained (see, for ex-ample, [39]).

2.6 Natural Polyacids

2.6.1 Polysaccharides

In the last years, special attention has been paid to modification of natural polymersproperties including imparting a functional carboxyl groups to them. Especially ithas been referred to the most widespread natural polymer, cellulose, which formsthe basis of cell walls of the highest plants. Sufficient mechanical strength, goodrheological properties, and possibility of application in fibers, filters, membranes,powders, or woven materials expand the areas of use of a macroligand which con-nects ions of various metals.

Chemical properties of cellulose are determined by presence of one primary andtwo secondary OH-groups in each elementary unit and also by acetal (glucoside)bonds between elementary units. High reactivity of cellulose allows to carry outnumerous chemical transformations with the purpose of obtaining various macroli-gands, including carboxyl groups (see, for example [40])), on the basis of cellulose.

Among other polysaccharides suitable for these purposes, we shall notestarch, dextrans, chitin, their dezacetylated derivatives, chitozane and pectins,and also alginic acids. Alginic acids are polysaccharides of algae which consist ofD-mannuric acid residues [41].

Carboxymethyl cellulose (CMC) is the most often used polymer for obtaining themetal containing polymers among natural polymers. CMC is a homogeneous pow-dery fine-dispersed polymer containing only carboxyl groups (up to 5�10�3 mol/g)which can participate in ionic binding at moderate pH (up to 10).

2.6.2 Humic Acids

Humic and fulvic acids are the most important natural macroligands. These acidsare the main organic producers of biogeocomplex, they are a mixture of the sametype of macromolecules of variable composition (Fig. 2.3) [42].

2.6 Natural Polyacids 23

Al2O3, Fe2O3

CaO

SiO2, P2O5

Mineral components

(CH3)2CHCH2CHNH2COOH

(C6H10O5)2

-(COOH)n, -(OH)n

-(NH2)n, -(CH2)n-

OH

O

Hydrolised components

C O

C OH

C

H

C C

H H

N

H

O C

H

HC C

HH

CH2

R1CH2

N

H

C

R3

H

C O

O

CH2CH2

C O

CHO H

R2

(CH2)n-

Core segment

N

H

CH

CO

O

R

N

H

C

H

C

O

N

H

C

H R

CO

OR

Lateral segment

OCH3

-O-C6H11O5

-O-C6H9O6

C O P O-

O-

O

O P O-

O-

O

CaOC

Complexes, sorption

Fig. 2.3 Formula of a structural unit of humic acid by D.S. Orlov (cit. on [42])

They are the most widespread complex substances determining migration andfastening of metal ions in soils.

Distribution of metal ions in various physicochemical phases renders a deter-mining influence on their mobility and bioaccumulation. In this connection, thecharged macromolecular ligands such as humic acids play a key role in localiza-tion and accumulation of metal ions in natural objects. Metal-binding properties ofhumic and fulvic acids have been intensively investigated in the last years [42–44].


These acids are obligatory and are the main unit in soil formation process and theyform a specific bioelements “depot,” which regulates a nutrition pattern of plantsdepending on environmental conditions.

The problem of complexation of heavy metals with these macroligands isimportant for the binding of their mobile forms. At last, complexation of metalions with humic acids plays an important role in the processes of migration anddelivery of biogenic metals into biological systems, in the ore formation processes,and for the solution of environmental problems. Macromolecules of humic acidscontain various functional groups differed by an acidity degree (see Fig. 2.3), eachgroup is the potential center of metal binding. Many kinetic regularities of humicacids complexation are similar to their synthetic analogs: centers formed underionization of weaker acidic groups enter the reaction with an increase in pH; anincrease in ionic strength induces an increment of their acidic properties, howevermuch, on the contrary, it influences the stability of metallocomplexes formed.

Thus, carboxyl groups are widely spread in numerous synthetic and naturalobjects. As it will be shown below, their metal-binding properties depend on manyfactors and, first of all, on composition and structure of a macroligand and its pre-history. Many of the necessary properties can be operated at the designing stage ofmacroligand and also by optimization of methods of binding of metal ions.

We do not analyze in this chapter substituted mono- and polycarboxylic acidscapable of participating in condensation processes, for example, m-carboranedicar-boxylic acid forming oligomerous salts with divalent metals, etc.

References

1. L.S. Luskin, Acrylic acid, methacrylic acid and the related esters, in: Vinyl and diene monomersPart 1, ed. by E.C. Leonard (Wiley, New York, 1971), pp. 105–262

2. N.A. Plate, E.V. Slivinskii, The Bases of Chemistry and Technology of Monomers (Nauka,Moscow, 2002)

3. Handbook of Chemistry and Physics, 76th edn., ed. by D.R. Lide (CRC Press, Boca Raton,New York, London, Tokyo 1995)

4. E.A. Bekturov, V.A. Myagchenkov, V.F. Kurenkov, Polymers and Copolymers of Styrene Sul-fonic Acid (Nauka, Alma-Ata, 1989)

5. C. Ohe, H. Ando, N. Sato, Y. Urai, M. Yamamoto, K. Itoh, J. Phys. Chem. B 103, 435 (1999)6. D. Bouyssi, J. Gore, G. Balme, Tetrahedron Lett. 33, 2811 (1992)7. V.V. Vintonyak, M.E. Maier, Org. Lett. 9, 655 (2007)8. V.A. Kabanov, D.A. Topchiev, Polymerization of Ionizing Monomers (Nauka, Moscow, 1975)9. Coulombic Interactions in Macromolecular Systems. ACS Symposium, Series 302, ed. by

A. Eisenberg, F.E. Bailey (American Chemical Society, Washington, DC, 1986)10. J. Choi, M.F. Rubner, Macromolecules 38, 116 (2005)11. M. Law, J. Goldberg, P.D. Yang, Annu. Rev. Mater. Res. 34, 83 (2004)12. A.F. Nikolaev, G.I. Okhrimenko, Water Soluble Polymers (Khimiya, Leningrad, 1979)13. S. Beuermann, M. Buback, P. Hesse, R.A. Hutchinson, S. Kukuckova, I. Lacik, Macro-

molecules 41, 3513 (2008)14. C. De Stefano, A. Gianguzza, D. Piazzese, S. Sammartano, J.Chem. Eng. Data 45, 876 (2000)15. C. De Stefano, A. Gianguzza, D. Piazzese, S. Sammartano, React. Funct. Polym. 55, 9 (2003)16. Polymer-Supported Reactions in Organic Synthesis, ed. by P. Hodge, D.C. Sherrington (Wiley,

Chichester, 1980)

References 25

17. G. Morawets, Macromolecules in Solutions (Mir, Moscow, 1970)18. L. Ruiz-Perez, A. Pryke, M. Sommer, G. Battaglia, I. Soutar, L. Swanson, M. Geoghegan,

Macromolecules 41, 2203 (2008)19. F. Fichtner, H. Schonert, Colloid Polym. Sci. 255, 230 (1977)20. P.L. Dublin, U.P. Stauss, J. Phys. Chem. 74, 2842 (1970)21. M. Abdollahi, A.R. Mahdavian, H.R. Buanzadeh, J. Macromol. Sci. Part A Pure Appl. Chem.

43, 1597 (2006)22. Handbook of Polyelectrolytes and Their Applications, ed. by S.K. Tripathy, J. Kumar,

H.S. Nalwa (American Scientific, Stevenson Ranch, CA, 2002)23. E.E. Makhaeva, H. Tenhu, A.R. Khokhlov, Macromolecules 35, 1870 (2002)24. Y. Ueba, K.J. Zhu, E. Banks, Y. Okamoto, J. Polym. Sci. Polym. Chem. Ed. 20, 1271 (1982)25. P. Monjol, C. R. Acad. Sci. 265, 1426 (1967); 266, 81 (1968)26. E.C. Kolawole, M.A. Bello, Eur. Polym. J. 16, 325 (1980)27. A. Chapiro, T. Sommerlatte, Eur. Polym. J. 5, 725 (1969)28. J.P. Jones, J. Polym. Sci. 33(126), 15 (1958)29. I.B. Lando, J.L. Koing, I. Semen, J. Macromol. Sci. B7, 319 (1973)30. K.M. Saldadze, V.D. Kopylova-Valova, Complexing Ionites (Complexites) (Khimiya,

Moscow 1980)31. G. Batterd, D.U. Treger, Properties of Grafted and Block-Copolymers (Khimiya,

Leningrad, 1970)32. A. Noshei, J. McGrat, Block-copolymers (Mir, Moscow 1980)33. A.D. Pomogailo, D.A. Kritskaya, A.P. Lisitskaya, A.N. Ponomarev, F.S. Dyachkovskii, Dokl.

Akad. Nauk SSSR 232, 391 (1977)34. D.A. Kritskaya, A.N. Ponomarev, A.D. Pomogailo, F.S. Dyachkovskii, J. Polym. Sci. Polym.

Symp. 68, 23 (1980)35. Plasmachemical Reactions and Processes, ed. by L.S. Polak (Nauka, Moscow, 1977)36. B.L. Tsetlin, A.V. Vlasov, I.Yu. Babkin, in Radiation chemistry of polymers (Nauka,

Moscow, 1973)37. B.L. Tsetlin, V.N. Golubev, Dokl. Akad. Nauk SSSR 201, 881 (1971)38. A.D. Pomogailo, Thesis PhD, Doct. Chem. (ICP AN SSSR, 1981)39. E.A. Hegazi, N.B. Al-Assy, A.M. Rabie, I. Ishigaki, J. Okamoto, J. Polym. Sci. Polym. Chem.

Ed. 22, 597 (1984)40. B.N. Stepanenko, Chemistry and Biochemistry of Polysaccharides (Vysschaya shkola,

Moscow, 1978)41. A.A. Muzzarelli, Natural Chelating Polymers (Pergamon Press, Oxford, 1973)42. Sh. Jorobekova, Macrolig and Properties of Humic Acids (Ilim, Frunze, 1987)43. J. Butfle, Complexation Reactions in Aquatic Systems (Ellis Horwood Ltd, Chichester, 1989)44. K. Kydralieva, Sh. Jorobekova, Metal Ions in Enzyme-Inhibitory Systems (Ilim, Bishkek, 2002)

Chapter 3Synthesis of Unsaturated Carboxylic Acid Salts

Prospective metal carboxylates of this type as subjects of various investigations,especially as potential monomers for the preparation of metallopolymers, attractthe attention of a large number of researchers to the development of methods fortheir synthesis. These efforts in particular are aimed at the design of geometri-cal, electronic, and other characteristics of the compounds to achieve the specifiedproperties.

The major distinctions between methods for the synthesis of unsaturated car-boxylic acids salts are in the type of the precursor metal compound employed andthe corresponding method for introduction of a ligand.

3.1 Reaction of Unsaturated Carboxylic Acids with MetalHydroxides, Oxides, and Carbonates

Neutralization reaction is widely used for the synthesis of unsaturated carboxylicacids salts. The essence of the method is dissolution of a metal oxide, hydroxide,or carbonate in a solution (commonly aqueous or aqueous-alcoholic) of the corre-sponding acid. The target product is isolated by evaporation of the resulting solutionuntil crystallization starts or by filtration of the precipitate if the metal carboxylateis insoluble or limitedly soluble in water [1–8].

Stoichiometric amounts of the starting materials or slight excess of an acid isadequate for use in the preparation of salts of the group I and II s-elements [9–13].In view of the high polymerizing ability of alkali metal (meth)acrylates, the reac-tion is usually carried out in dilute solutions at reduced temperature, and often inthe presence of special compounds that inhibit polymerization [14–16]. In manycases, if the salts formed are readily hydrolyzed, an excess of the acid has to beused or water has to be removed by either azeotrope distillation or by binding itwith another substance. Thus, anhydrous calcium acrylate and methacrylate weresynthesized at 40–100ıC in hydrocarbon solvents followed by azeotrope distilla-tion and drying [17]. Also, there have been patent reports on the preparation of(meth)acrylates of lanthanoids [18] or Zn [19] in two-phase aqueous-organic or or-ganic media. Acrylates and methacrylates of d -elements are synthesized according


27

28 3 Synthesis of Unsaturated Carboxylic Acid Salts

to this method in alcoholic or hydrocarbon (benzene, toluene) suspensions [20–25].The use of nonaqueous media decreases the probability of formation of basic saltsand favors the preparation of the purer reaction products in high yields (higher than95% in the case of Zn(II), Co(II), Ni(II), and Cu(II) with double bond content higherthan 94%). In the case of triple charged metal cations, for example, Fe(III), Cr(III),and so on, depending on the reaction conditions and the reactant nature, either nor-mal salts [26–29] or trinuclear oxo-carboxylates are formed (see Sect. 2.3).

Metal dicarboxylates appear to behave similarly. Thus, maleic acid upon re-action with zinc oxide in an aqueous medium reacts as monobasic acid givingrise to a mixed complex, ZnH(OOCCHDCHCOO)(OH)�H2O, whereas under thesame conditions in methanol it behaves as a dibasic one [13]. The complexation ofmetal ions with dicarboxylic acids was studied by potentiometric titration [30–34]and spectrophotometric analysis [32, 35]. For example, it was found that 1:1 com-plexes are formed at pH 4.9–5.2 in the copper(II) – maleic acid system [32]while in the thallium(III) – fumaric (or maleic) acid system at pH 2.0–3.5 [30].Neutral M.C6H4O4/C and protonated MH.C5H4O4/2C complexes coexist in the4f -element metal ion – itaconic acid system at pH 3–4 [33], which was confirmedby preparative isolation of the neutral itaconates M2.C5H4O4/3�nH2O .n D 3 � 6/

and the protonated complexes MH.C5H4O4/2 � nH2O .n D 1; 2/ [36–38]. Stabilityconstants for neutral complexes are higher than lg K values for the protonated com-plexes, thus correlating with the disassociation constants for the acid .K1D .1:62˙0:19/� 10�4; K2 D .4:39˙ 0:18/� 10�6/ (Table 3.1).

An interesting modification of this method consists of preparation of the metalhydroxide in situ [39], if one of the products is poorly soluble, the reaction proceedsto completion [40, 41]. Thus, the reaction of beryllium sulfate, maleic acid, andbarium hydroxide in a 1:2:1 molar ratio in water results in immediate precipitationof barium sulfate.

BeSO4 C Ba .OH/2 C C4H4O4 ! BaSO4 C Be .C4H2O4/ 2H2O

This is an example of the successful preparation of beryllium(II) carboxylate com-plex in an acidic medium. Monocarboxylic ligands are involved in the berylliumcoordination sphere only in alkaline or neutral media to give oxo-carboxylates(RCOO)6(Be4O) [42].

Table 3.1 Logarithms of the constants of stability (lg K) of itaconate complexes for the composi-tions of MLC and MHL2C

Ion of 4f-element lg KMLC lg KMHL

2C Ion of 4f-element lg KMLC lg KMHL

2C

Lanthanum 2.52 ˙ 0.20 1.56 ˙ 0.20 Terbium 3.05 ˙ 0.22 1.87 ˙ 0.12Cerium 2.78 ˙ 0.24 1.78 ˙ 0.13 Dysprosium 2.90 ˙ 0.25 1.82 ˙ 0.14Praseodymium 3.02 ˙ 0.19 1.91 ˙ 0.22 Holmium 2.66 ˙ 0.28 1.64 ˙ 0.17Neodymium 2.95 ˙ 0.24 1.98 ˙ 0.12 Erbium 3.18 ˙ 0.05 1.77 ˙ 0.20Samarium 3.10 ˙ 0.23 1.96 ˙ 0.11 Thulium 2.45 ˙ 0.17 1.57 ˙ 0.16Europium 3.33 ˙ 0.18 1.98 ˙ 0.09 Ytterbium 2.62 ˙ 0.18 1.61 ˙ 0.17Gadolinium 3.06 ˙ 0.38 1.91 ˙ 0.16 Lutecium 2.80 ˙ 0.24 1.65 ˙ 0.14

3.2 Reactions of Acetates and Other Salts with Unsaturated Carboxylic Acids 29

3.2 Reactions of Acetates and Other Salts with UnsaturatedCarboxylic Acids

This method is well known for the synthesis of saturated metal carboxylates [43].Availability of the starting materials, volatility of the acids evolved, and the fact thatcarboxylic acids could be taken in stoichiometric amounts are advantages of themethod. The drawbacks include frequent contamination of the products by tracesof acetic acid and, in the case of salts of strong acids, side reactions, in particularpolymerization. To prevent undesired processes, proton acceptors, such as calciumor sodium carbonates [44–46], are usually employed. Alternatively, the reaction iscarried out under inert atmosphere and moderate temperature [47].

The reaction under discussion appeared to be very efficient for the synthesis ofoxopolynuclear Mn12 (meth)acrylates. These important substances exhibit molec-ular magnet properties and are monomeric precursors for the polymeric analogs[48–50]. Equilibrium of the reaction is shifted by vacuum removal of the formedCH3COOH, and the repeated reaction with excess of unsaturated acid yields fullsubstitution by (meth)acrylate ligands.

ŒMn12O12.CH3COO/16.H2O/4�C 16CH2C.CH3/COOH$ŒMn12O12.CH2C.CH3/COO/16.H2O/4�C 16CH3COOH

There are no principal limitations for the synthesis of heterometallic polynu-clear complexes like [Mn10Fe2O12(CH2C(CH3)COO)16(H2O)4] according to thisscheme [50].

Hydrothermal syntheses, which are of interest for the design of new materialswith unusual structures, have been intensely developed in recent years [51]. Theseapproaches are applicable mainly for dicarboxylate ligands that have low reactivitytoward homopolymerization. Thus, the reaction of copper(II) acetate monohydratewith fumaric acid under mild conditions gives air-stable copper(I) fumarate withhigh density .d D 3:24 g cm�3/ [52]. The essence of the method is as follows: start-ing materials are placed in a autoclave and kept there for 1.5 days at 150ıC. Thecrystals formed are isolated, washed with water, and dried. This method typicallygives rise to more condensed products with two- or three-dimensional spatial struc-ture (Fig. 3.1) [53].

For example, lanthanoid fumarate complexes, [Ln2(OOCCHDCHCOO)3

(H2O)4]�3H2O (Ln D Sm(III) [54] and Eu(III) [55]), contain less H2O moleculesthan compounds [Ln2(OOCCHDCHCOO)3(H2O)4]�8H2O [56], obtained in so-lution at room temperature, while both have the same Ln/fumarate ratio (2:3).Tetranuclear Zn(II) fumarate complex, [Zn4(OH)2((OOCCHDCHCOO)3(4; 40-bipy)2] [57], that was synthesized in an analogous way exhibit rather high thermalstability (up to 380ıC). It should be noted that products of the hydrothermal synthe-sis are often studied by supramolecular chemistry due to a combination of complexstructures and unusual properties.


Fig. 3.1 Changing of the phases of cobalt succinate, from low temperature (60ıC, far left) to hightemperature (250ıC, far right)

Metal acetylacetonates are often utilized as starting materials. This method isespecially efficient for the preparation of complexes with different ligands. Mixedlanthanoid complexes (Nd3C, Eu3C, Gd3C, and Yb3C) with benzoylacetone [58]or acetylacetone [59, 60] and unsaturated acids (acrylic, methacrylic, fumaric, andmaleic) were synthesized by reaction of the acid with benzoylacetonate or acety-lacetonate of an f -element in dioxane. Interaction of terbium tris(acetylacetonate)with maleic acid [61] is exothermic over the concentration range of (3–6) �10�2 and 0.5 M for the metal salt and the acid, respectively (�H D � 8:2 ˙0:4 kJ=mol; �GD 17:0 ˙ 0:8 kJ=mol; �S D 29:4˙ 1:6 J=K mol; lgKD 2:97 ˙0:06, dioxane, 298 K). The change in the enthalpy can be attributed to a numberof factors, including the formation of a stronger bond of the ligand with the Tb3Cion upon substitution of the acetylacetonate for the maleate anion. Examples ofsuch stabilizing effect of the maleate ligand are rather frequent. The kinetic studies[62] for the interaction of Pd.H2O/4

2C with maleic acid revealed that the reac-tion proceeds with a stoichiometric ratio 1:1 according to a complex mechanismvia a series of sequential and parallel reactions of the A $ B ! C type. In thefirst stage, an intermediate product, cation [Pd(H2O)3OOCCHDCHCOOH]C, isformed with stability constant K D 205 ˙ 40 M�1. Two parallel reversible reac-tions with the participation of maleic acid and hydromaleate anion, respectively,give rise to the formation of the cation. In the next step, a slow intramolecularcyclization (rate constant 0:8˙ 0:1 s�1) or a nucleophilic attack of the intermediateB by the carboxylate or the acid molecule leads to a creation of the olefin complex[Pd(H2O)2OOCCHDCHCOOH.

3.3 Ligand Exchange Reactions

These reactions are the most common for synthesis of the complexes and are usedfor the exchange of inner-sphere as well as outer-sphere ligands. Not only substi-tution of solvent molecules but also substitution of other ligands by the desired

3.3 Ligand Exchange Reactions 31

ligand can take place upon this transformation. The method is often employed forthe exchange of group I s-elements for f -elements and is particularly efficient whenno stable soluble metal salts are available.

3.3.1 With Metal Halides

Mono- and disubstituted unsaturated acyl derivatives of bis(cyclopentadienyl)titanium were first obtained by A.N. Nesmeyanov et al. [63] by the reaction ofbis(cyclopentadienyl)titanium dichloride with salts of methacrylic acid. Monomericcompounds of this type are readily soluble in benzene, acetone, DMF, pyridine,partially soluble in MMA [64]. The general scheme for their synthesis could bepresented as follows (Scheme 3.1).

Similar routes can be used for the preparation of titanium dicarboxylate deriva-tives [65–69]. The main drawback for the method is formation of large amounts offinely dispersed chlorides that are difficult to remove. A promising way to solve thisproblem is to carry out synthesis of the alkyl orthotitanates Ti.OR/4�n.OR0/n, ina system of two immiscible solvents, one of which dissolves the resulting salt andthe other dissolves the alkyl orthotitanate [70]. There are known examples of us-ing liquid ammonia as the solvent, as it dissolves ammonium chloride but does notdissolve alkyl orthotitanate. This method ensures good yields but requires elevatedpressure in each stage of the process.

Ti ClCl

Ti

Ti ClTiCl

C

O

OCH2C

H3C

H2C

H3CC

O

O CH

TiO

O

O C

CH3

CH2

C

O

OC

C

O

O C CH2

CH3

Ti

Ti

C

C

C

C

O O

O O

C

CC

C

OO

OO

HOOC

Ti

Ti

CC

C

C

OO

OO

HC

HCHOOC COOH

H

H

2CH2 = C(CH

3 )COOK

CH 2 =

C(C

H 3)C

OOK

CH2 = C(CH

3 )COOK

CH2

CH 2 =

CHCOOH

COOHCC

C 2H 5

OH

C2H5O C

Scheme 3.1 The general scheme of synthesis of unsaturated acid derivatives of bis(cyclo-pentadienyl) titanium (IV)


3.3.2 With Metal Alkoxides

Metal carboxylates are often prepared by the reactions of metal alkoxides withorganic acids or acid anhydrides. Titanates Ti.OR/3OCOC.CH3/ D CH2 (R Dt-butyl, t-pentyl, t-ethylhexyl) were obtained by nucleophilic substitution fromtitanium(IV) alkoxide and methacrylic acid taken in a stoichiometric ratio [71]. In asimilar way dibutoxybis(butylmaleinate)titanium was synthesized upon treatmentof Ti(OBu)4 with maleic anhydride in a 1:2 molar ratio [72]. If the released alcoholhas higher boiling temperature than the acid, or if the precursor metal tetraalkoxideis unavailable, the reaction is carried out in two steps:

CH2 = CCOOH

Ti(OR)4 + ROH+COOTi(OR)3

+ 3 HOCH2CH(CH2CH3) – (CH2)3 – CH3

+ 3 ROHCOOTi(OCH2CH(CH2CH3) – (CH2)3 – CH3)3

CH3CH2 = C

CH3

COOTi(OR)3

CH2 = CCH3

CH2 = CCH3

The released alcohol is removed by continuous evaporation under reduced pres-sure. Note that these syntheses were carried out without a solvent. Very high yields(up to 97%) of the target products attest to a low contribution of side processes, forexample, polymerization transformations, that are possible under these conditions.In general, employment of acid trans-esterification requires special care as a fewother side reactions, such as esterification of the precursor acid with the releasedalcohol, hydrolysis of the titanium ester by the latent water, formation of titaniumoxide compounds like TiOx(OOCR)4�2x (x D 0:5 or 1) can take place [73]. Toavoid these complications utilization of the acid anhydrides is more efficient for theintroduction of unsaturated acyl residues into metal alkoxides:

Ti(OR)4 + n(CH2 = C–CO)2O

n = 1; 2

(CH2 = C–COO)n Ti(OR)4 – n + nCH2 = C–COOR

CH3

CH3

CH3

Employment of metal alkoxides as a precursor is particularly important whencoordination of a water molecule need to be avoided, as it is known to causeluminescence quenching for the compounds of f -elements. Therefore, an alter-native method for the synthesis of anhydrous europium(III) methacrylate fromeuropium triisopropoxide in organic medium has been proposed, which differsfrom standard methods for the preparation of f -element complexes in aqueoussolutions [74]. This method is also convenient for the preparation of hetero-ligandcomplexes (Scheme 3.2) [75].

3.3 Ligand Exchange Reactions 33

Eu2O3 EuCl3Na(OiPr) / iPrOH /benzene

Eu(OCHCH3)3

CH3

β−diketone /AA / iPrOH /benzene

C

O O

EuOC

HC C

O

OC

CHC

O

R1R1

R2 R2

R1 = CH3, R2 = CH3

R1 = CH3, R2 =

R1 = CF3, R2 =S

R1 = , R2 =

CHH2C

HCl /NH4Cl

Scheme 3.2 Synthesis of the monomeric hetero-ligand europium(III) complex

According to this scheme, in the first stage, a reactive isopropoxide ofeuropium(III) is formed. Its reaction with acrylate and “-diketonate ligands inthe mixture of organic solvents results in the formation of monomeric europium(III)complex without coordinated water molecules.

3.3.3 Other Exchange Reactions

Liquid crystal monomeric complexes of Mg(II) and Zn(II) were prepared by inter-action of chlorides or sulfates of the metals with sodium salt of the correspondingunsaturated acid in water [76].

MgCl2 � 6H2OC 2NaO2CR! Mg.O2CR/2 � xH2OC 2NaClC .6 � x/H2O

.R D .CH2/11OCOCH D CH2IC6H3.O.CH2/11OCOCH D CH2/2I x D 0; 2/

Target products are separated by filtration or by extraction with chloroform oracetone. Mn(II) (meth)acrylate [77] and dicarboxylate [78] complexes were synthe-sized according to the same scheme using methanol as a solvent. Employment ofammonia in exchange reaction of this type often promotes formation of soluble car-boxylate complexes, in particular this is common for copper(II) [79]. In some casesprecursor carboxylate of an s-metal is prepared in situ. Complexes of europiumand terbium with cinnamic acid and other ligands of formula Ln.OOCCHDCHC6H5/�nD�xH2O, where Ln D Eu(III), Tb(III), D D 1,10-phenantroline (phen),2; 20-dipyridine (2; 20-dipy), benzotriazol (bta) .n D 2; x D 0/, triphenylphosphi-noxide (tphpho) .n D 1; x D 2/ were synthesized according to this route [80].

Complexes of varied composition can be synthesized depending on the reactionconditions. For example, binuclear copper hydromaleinate solvated with ethanolmolecules is formed when exchange reaction is conducted in organic medium,whereas the presence of water fosters transformation of the complex into a mononu-clear hydrate, Cu(OCOCHDCHCOOH)2�4H2O [46]. Tendency of copper(II) ionstoward hydration diminishes upon increase of reaction temperature.


Binuclear cromium(II) acrylate was synthesized by treatment of cromium(II)chloride with sodium acrylate under inert atmosphere [81]. This compoundappeared to be extremely sensible to oxygen and self-ignited when exposed to air.

3.3.4 Synthesis of Bimetallic Compounds

One of the variations of exchange reactions is a combined synthesis of heterometal-lic carboxylates. In a typical procedure, to a solution of metal M1 carboxylate asalt of another metal M2 is added followed, if necessary, by a carboxylate and anaccompanying ligand. The target complex is isolated by filtration or crystallization.Heteronuclear carboxylates containing ions of d - and f -elements were synthesizedusing this approach [82–84]. The bimetallic maleinate CuxZn1�xC4H2O4�2H2O.x D 0:06/ was isolated from solutions of copper and zinc maleinates upon slowevaporation at 60ıC.45 In a similar way heterometallic trinuclear crotonates weresynthesized with yields higher than 80% [85].

3.4 Sol–Gel Reactions

Sol–gel synthesis techniques are promising for the preparation of metal carboxy-lates of the type under consideration. These techniques are based on hydrolysis ofalkoxides M(OR)4 in an organic medium followed by condensation of the resultedproducts leading to gel formation [86, 87]. The presence of carboxylic group in thealkoxide molecule allows regulating its reactivity due to the formation of latent wa-ter to conduct controlled hydrolysis and growth of the carboxylate-substituted metaloxo clusters. There are numerous examples of this type of reaction. Thus, the re-action of zirconium(IV) or hafnium(IV) alkoxide with excess methacrylic acid inpropyl alcohol affords polynuclear oxo-carboxylate [88,89]. Note that in an attemptto replace the chelating methacrylate groups by acetylacetonate (AcAc) groups, thezirconium oxo cluster Zr4O2.OOCC.CH3/DCH2/12 prepared by the method de-scribed above were converted into a mononuclear complex [90]:

Zr4O2.OOCC.CH3/ D CH2/12 C 8AcAc �H! 4Zr.AcAc/2.OOCC.CH3/

D CH2/2 C 4CH2 D C.CH3/COOHC 2H2O

This example attests that the subsequent modification of the resulting oxo clus-ter molecule seems to be impeded. It was shown that the clusters Zr6O4(OH)4

(OOCR)12 and [Zr6O4(OH)4(OOCR)12]12 (RCOO – methacrylate [91] or acrylate[92]) do not interconvert [93], although they are structurally related and rather la-bile in solution due to carboxylate ligand exchange. Using exchange reactions, it ispossible to replace all or some methacrylate ligands in Zr6O4(OH)4(OOCR)12 byother carboxylate ligands, for example, propionate or isobutyrate [94]. The complexZr6O4.OH/4.O2CC.CH3/DCH2/8.O2CCH.CH3/2/4(BuOH) was also synthesized

3.5 Other Reactions 35

directly by the reaction of Zr(OBu-n)4 with a mixture of methacrylic and isobu-tyric acid. There have been reported examples of metal alkoxides modification byunsaturated ligands, such as itaconic acid anhydride [95, 96], acetoacetoxyethylmethacrylate [96, 97], p-vinylbenzoic, and p-vinylphenylacetic acids [96].

The key factors used to efficiently control the composition and the size ofthe formed oxo clusters include the molar ratio of an organic acid and a metalalkoxide and the nature of the metal alkoxide. For example, the reaction oftin(IV) isopropoxide with different acids including methacrylic at an equimo-lar reactant ratio results in the formation of a dimer with six-coordinated tinatoms, while at the reactant ratio between 1.4 and 2 the reaction gave rise tocompounds [Sn(�2-OiPr)(OiPr)(O2CR)2]2 (R D (Me)CDCH2, C6H5, CH3)[98]. However, no polynuclear oxo complexes were obtained in the reactioneven when the molar ratio of RCOOH to Sn(OiPr)4 was greater than 2, uniden-tified polymers being the final products of the reaction. It was found that thehighest molar ratio of an acid to titanium(IV) alkoxide leading to formationof the oxo cluster Ti6O4(OEt)8(OOC(Me)DCH2/8 is 1.33 [99]. At higher ra-tios polymeric or oligomeric structures are formed, as, for example, in thecase of Ti9O8(OPr)4(OOC(Me)DCH2/16 [100]. The attempts to prepare yt-trium oxo-carboxylate complexes failed. Only anhydrous yttrium methacrylateY(OOCC(Me)DCH2/3 was isolated after esterification and characterized by X-raycrystallography [101]. However, mixed oxo complexes with different compositionsand structures based on yttrium(III) and titanium(IV) with methacrylate ligandswere synthesized in quantitative yields [102].

Similar synthetic approaches are applicable for the preparation of heteronuclearcomplexes [103–105]. Thus, upon variation of the ratio of starting alkoxides com-plexes of the varied composition could be obtained, for example, for 1:1 and 1:2ratios of titanium and zirconium alkoxides, the complexes Ti4Zr4O6.OBu/4.CH2 DC.CH3/COO/16 and Ti2Zr4O4.OBu/2.CH2 D C.CH3/COO/14, respectively, wereobtained [106].

3.5 Other Reactions

Some fumaric acid salts are obtained by catalytic isomerization of maleic anhydridefollowed by the reaction of the resulting acid with a metal compound. For example,iron(II) fumarate was prepared using maleic anhydride in the presence of thiourea[107] or hydrochloric acid [108]. Subsequent transformations of the fumaric acidcan be carried out in accordance to one of the above mentioned methods. Unusualtrans addition reaction of HCl to triple bond of the unsaturated ligand leading toformation of copper(II) chlorofumarate f[Cu(OOCCHDCClCOO)(H2O)2]�H2Ognwas observed in the aqueous solution of acetylenedicarboxylic acid and CuCl2[109, 110]. Metal complexes of Shiff bases are convenient reactants for the prepa-ration of carboxylate complexes. Thus reaction of Fe(III) complexes withthe tetradentate ligands N; N 0-bis(salicylidene)ethylenediamine (salenH2) orbis(salicylidene)-o-phenylenediamine (salophH2) with acetylenedicarboxylic acid


solution in BuOH resulted in the formation of the binuclear Fe(III) complexes[fFe(salen)g2(OOCC�CCOO)] and [fFe(saloph)g2(OOCC�CCOO)] with dicar-boxylate bridges [111].

Examples of employment of organometallic compounds as starting reagents arenot rare [112–115]. For example, the reaction of pentaphenylantimony with maleicacid at room temperature results in the cleavage of the M�C bond to yield Sb(V)acyl derivatives [112].

Ph5SbC HO.O/C� CH D CH � C.O/OH! Ph4Sb �O.O/C � CH

D CH � C.O/OHC PhH

Change in the molar ratio of the reagents allows synthesizing disubstituted carboxy-lates. It should be noted that the resulting products are moisture sensitive and areeasily hydrolyzed.

Antimony (or bismuth) carboxylates can also be prepared in one step uponoxidation of triphenylantimony (or triphenylbismuth) with t-butylhydroperoxideor hydrogen peroxide in the presence of acrylic acid according to the followingscheme [116]:

Ph3MCROOHC2CH2DCH�COOH! Ph3M.CH2 D CH�COO/2CROHCH2O

M D Sb; BiIR D t � Bu; H

Reaction proceeds smoothly in ether at room temperature with yields ranging50–90%.

An unexpected product was obtained in the reaction of equimolar amountsof trimethylstannanol with maleic anhydride [113]. Irrespective of the reactionconditions, bis(trimethylstannyl) maleate is formed rather than the expected mono-substituted derivative:

Sn

H3C

H3C

H3C O

H

Sn

CH3

CH3

CH3O

H

CH CH

C CO

OO

+Sn(CH3)3

Sn(CH3)3HC

HC

C

C

O

O

O

O–H2O

This reaction route is apparently related to the dimeric structure of the original tinreagent. When aryl tin hydroxides are involved in the reaction, one aryl group iseliminated giving rise to cyclic organotin maleate:

CH CH

C CO

OO

Ar3SnOH + SnHC

HC

C

C

O

O

O

O+ ArH

Ar

Ar

3.6 Synthesis of Cluster Containing Unsaturated Carboxylates 37

Organolead maleates were prepared in a similar way. Organotin (organolead)maleates are solid compounds, soluble in organic solvents, and crystallized asneedles or plates. In some cases alkylmetal hydroxide for the above reaction is pre-pared in situ [117]. For example, synthesis of the dimethylthallium(III) propionateis carried out according to the following scheme:

Ag2OTl I OH

CH C COOH OOC C CHH2O, 2 h, –AgI

H3C

H3C

TlH3C

H3CTl

H3C

H3C

A peculiar reactivity of allyltitanocene compounds toward certain substances,such as carbon dioxide can result in the formation of carboxylates [118, 119]. Thereaction with CO2 proceeds as an insertion into the Ti� ˜3 – allyl bond:

R

CO2 R

CO O

O CO

RO

C

O R

(C5H5)2Ti (C5H5)2Ti

(C5H5)2Ti(C5H5)2Ti

It has been demonstrated by theoretical [120, 121] and experimental [122–125]studies that the key step in the catalytic reaction of CO2 with ethylene is alsothe formation of mono- and binuclear acrylate complexes, including hydrido acry-late forms:

O

H

PhMe2P

Mo

Mo

O

O

O

WP

P PMe3

H

O

O

PMe2Ph

PMe2Ph

PMe2Ph

3.6 Synthesis of Cluster Containing Unsaturated Carboxylates

Synthesis of cluster containing carboxylates, that are molecular compounds havingmetal–metal bonds and ligands capable to polymerize, seems to have prospective.There are two main approaches developed for the synthesis of cluster contain-ing monomers. One approach is based on the introduction of a ligand capableto polymerize into a polynuclear complex, for example, substitution of the exist-ing ligand with an unsaturated one, their oxidative addition, or addition to double


M�M bond under mild conditions and so on. Another approach is building up thecorresponding ligands with clusters [14]. Carboxylates were synthesized with highyields using as precursors trinuclear carbonyl clusters Os3(CO)12 and its derivativesOs3(CO)11(CH3CN), (��H)Os3 (CO)10(�-OR) (RD H, Ph) [126, 127]:

H

O OC

CH=CH2

HOs(CO)3 Os(CO)3(CO)3Os (CO)3Os

Os(CO)4 Os(CO)4

O

Ph

CH2 = CHCOOH

80°C, benzene, 14 h

Outer sphere substitution principle was utilized in a series of consequent synthe-ses of Mo6 cluster carboxylates [128, 129].

.Bu4N/2 Œ.Mo6Cl8/Cl6�CF3COO�

��! .Bu4N/2 Œ.Mo6Cl8/.CF3COO/6�

CH2DCHCOO�

��! .Bu4N/2 Œ.Mo6Cl8/.CF3COO/6�n.CH2 D CHCOO/n�

The main problem of carrying out this type of reaction, namely the problem ofsubstitution of all six outer sphere chlorine atoms with other outer sphere ligands,has been solved in recent years. This was achieved by the employment of inter-mediate triflate groups CF3COO�, which could be easily substituted under mildconditions with acrylate groups. The number of triflate groups substituted the acry-late groups was found by the ratio of integral intensities for the protons N.Bu4/C(N�CH2� group) and groups CH2DCHCOO� in the 1H NMR spectra to bebetween 1 and 3 [130].

The methods discussed are applicable for the design of monomeric carboxylatesbased on the heteropolynuclear clusters as well [131].

Therefore, it can be concluded that methods of synthesis of unsaturated car-boxylic acid salts are fairly diverse. In most cases, they are similar to the methodsand procedures used to synthesize saturated metal carboxylates, except for the fu-sion technique. The last mentioned technique is widely used in industry to obtainanhydrous saturated carboxylates in good yields; however, it has limitations for un-saturated carboxylates due to possible polymerization even during the synthesisof the monomer. It should be emphasized that readily hydrolysable carboxylates,for example, acyl derivatives of metal alkoxides are synthesized in nonaqueousmedia. As it has been mentioned above, characteristic features of the reaction cho-sen determine the peculiar properties of the product obtained, i.e., the carboxylateswith the specified structure and composition can be obtained by purposeful changein conditions for the synthesis. The summary table can be presented as follows(Table 3.2). Practically all toolbox of the preparative inorganic and organometallicchemistry methods is utilized for the synthesis of unsaturated metal carboxylates,yet in some cases development of special techniques is required.


Tab

le3.

2Sy

nthe

sis

and

som

ech

arac

teri

stic

sof

unsa

tura

ted

met

alca

rbox

ylat

es

Star

ting

reag

ents

Met

alca

rbox

ylat

esA

cids

Met

alco

mpo

unds

Rea

ctio

nco

ndit

ions

The

char

acte

rist

ics

Ref

.

Inte

ract

ions

ofm

etal

(hyd

ro)o

xide

san

dca

rbon

ates

wit

hun

satu

rate

dca

rbox

ylac

ids

Met

al(m

eth)

acry

late

sN

a.C

H2

DC

HC

OO

/A

AN

aOH

pHD

7.0

˙0.

1[9

]B

a.C

H2

DC

.CH

3/C

OO

/ 2�H

2O

MA

AB

a(O

H) 2

Hot

H2O

,cry

stal

liza

tion

[132

]

Ba.

CH

2D

C.C

H3/C

OO

/ 2B

a(II

)m

etha

cryl

ate

hydr

ate

Deh

ydra

tion

,vac

uum

,50

ıC

orre

crys

tall

izat

ion

indr

ym

etha

nol

[132

]

Li.

CH

2D

C.C

H3/C

OO

/M

AA

Li 2

CO

3M

etha

nol,

15

ıC

,har

dst

irri

ng,p

reci

pita

tion

wit

hdi

ethy

leth

er.

�as

.CO

O/

D1;5

72I�

s.C

OO

/D

1;4

23

cm�

1

[10]

Na.

CH

2D

C.C

H3/C

OO

/M

AA

Na 2

CO

3T

hesa

me

�as

.CO

O/

D1;5

58I�

s.C

OO

/D

1;4

19

cm�

1

[10]

Cu 2

.CH

2D

C.C

H3/C

OO

/ 4�2H

2O

MA

A.C

uOH

/ 2C

O3

Met

hano

l,24

h,st

irri

ng,

then

boil

ing

5h,

crys

tall

izat

ion

at�2

0ı

C,�

12h

�ef

fD

1:3

5�

B(2

98K

),�

max

D722,

364

nm,

MD

483

(osm

omet

ry,i

nbe

nzen

e)

[25]

(con

tinu

ed)


Tab

le3.

2(c

onti

nued

)

Star

ting

reag

ents

Met

alca

rbox

ylat

esA

cids

Met

alco

mpo

unds

Rea

ctio

nco

ndit

ions

The

char

acte

rist

ics

Ref

.

Cu 2

.CH

2D

C.C

H3/C

OO

/ 4�2P

y�

eff

D1:3

9�

B(2

98K

),�

max

D749,

384

nm,

MD

614

(osm

omet

ry,i

nbe

nzen

e)

[25]

Cu 2

.CH

2D

C.C

H3/C

OO

/ 4�2(

4-V

Py)

�ef

fD

1:4

5�

B(2

98K

),�

max

D746,

386

nm,

MD

689

(osm

omet

ry,i

nbe

nzen

e)

[25]

M.C

H2

DC

HC

OO

/ 2�nH

2O

;

MD

Zn.

II/,

Co(

II),

Ni(

II),

Cu(

II)

AA

Met

alhy

drox

ides

,(h

y-dr

o)ca

rbon

ates

Met

hano

l,D

MFA

,be

nzen

e,to

luen

e,st

irri

ng5

h,pr

ecip

itat

ion

wit

hdi

ethy

leth

er,a

ceto

ne

Dou

ble

bond

s>

94%

,�

as.C

OO

/D

1;5

20–1

;575

cm�

1;

�s.

CO

O/

D1;3

60–1

;370

cm�

1

[20,

21]

ŒM3O

.CH

2C

HC

OO

/ 6�

3H

2O

�OH

;M

DFe

.III

/,C

r(II

I),V

(III

)

AA

Met

alhy

drox

ides

Met

hano

l,et

hano

l,st

irri

ng3–

5h,

prec

ipit

atio

nw

ith

diet

hyle

ther

[22,

23]

Fe.C

H2

DC

.CH

3/C

OO

/ 3M

AA

NaH

CO

3,F

eCl 3

H2O

;40

ıC

[40]

(con

tinu

ed)


Tab

le3.

2(c

onti

nued

)

Star

ting

reag

ents

Met

alca

rbox

ylat

esA

cids

Met

alco

mpo

unds

Rea

ctio

nco

ndit

ions

The

char

acte

rist

ics

Ref

.

Cu 2

ŒCH

2D

C.C

H3/C

OO

� 4.H

2O

/ 2

MA

AC

u 2.O

H/ 2

CO

3B

oili

ng2

h,m

etha

nol

�as

.CO

O/

D1;5

72

cm�

1;

�s.

CO

O/

D1;4

15

cm�

1

[24]

Met

aldi

carb

oxyl

ates

Co.

HO

OC

CH

DC

HC

OO

/ 2�5H

2O

Mal

AC

oCO

3H

otH

2O

,sti

rrin

g,pH

D7

[44]

Ni.

OO

CC

HD

CH

CO

O/�2

H2O

Mal

AN

iCO

3T

hesa

me

[44]

Cu.

OO

CC

HD

CH

CO

O/�H

2O

Mal

A(C

uOH

) 2C

O3

The

sam

e[2

]Z

nH.O

OC

CH

DC

HC

OO

/.O

H/

�H2O

Mal

AZ

nOH

2O

,sti

rrin

g,60–7

0ı

CIR

:3,4

00,3

,575

,1,

190–

1,12

5,1,

310–

1,35

0cm

�1

[13]

Be.

OO

CC

HD

CH

CO

O/�2

H2O

Mal

AB

eSO

4�4H

2O

,B

a(O

H) 2

�8H2O

H2O

,sti

rrin

g17

h,bo

ilin

g3

h,pH

D3,

crys

tall

izat

ion

1H

-NM

R(D

2O

,20

ıC

):ı

D6:0

5,

s,2H

,CH

;13C

f1H

gNM

R:

ıD

133:3

,2C

,C

H;9

Be

NM

R:

ıD

1:2

1,s

,1B

e

[41]

(con

tinu

ed)


Tab

le3.

2(c

onti

nued

)

Star

ting

reag

ents

Met

alca

rbox

ylat

esA

cids

Met

alco

mpo

unds

Rea

ctio

nco

ndit

ions

The

char

acte

rist

ics

Ref

.

.NH

4/ 2

ŒBe.

OO

CC

HD

CH

CO

O/�

Mal

A25

%N

H4O

H,

BeS

O4�4H

2O

,B

a(O

H) 2

�8H2O

H2O

,sti

rrin

g16

h,bo

ilin

g5

h,pH

D5.

5,cr

ysta

lliz

atio

n

1H

-NM

R(D

2O

,20

ıC

):ı

D6:0

2,

s,2H

,CH

;13C

f1H

gNM

R:

ıD

134:6

,2C

,C

H,1

71.2

,2C

,C

OO

;9B

eN

MR

:ıD

2:0

2,

s,1B

e

[41]

AgO

OC

CH

DC

HC

OO

HM

alA

Ag 2

CO

3H

otH

2O

,sus

pens

ion

[5]

CuO

OC

CH

DC

HC

OO

H�H

2O

Mal

A(C

uOH

) 2C

O3

The

sam

e[4

]

Cd.

OC

OC

HD

CH

CO

O/�H

2O

Mal

AC

dCO

3H

2O

susp

ensi

on,

exce

ssof

carb

onat

e

[133

]

Cd.

OC

OC

HD

CH

CO

O/�H

2O

Mal

AC

dCO

3H

2O

susp

ensi

on,

carb

onat

e:ac

idD

1:2

(mol

)

[134

]

LnH

.CH

2D

C.C

OO

/CH

2C

OO

/ 2�

nH

2O

;n

D1;

1.5;

2;L

nD

La,

Ce,

Pr,N

d,Sm

,E

u,G

d,T

b,D

y,H

o,L

u,E

r

ItA

Rar

eea

rth

elem

ents

carb

onat

esH

2O

,con

c.ac

idso

luti

on�

as.C

OO

/D

1;5

40–1

;580

cm�

1;

�s.

CO

O/

D1;3

00–1

;335

cm�

1,

prod

ucto

fso

lubi

lity

–10

�8,

Kst

abil

ity

D6:0

�10

3�

1:2

5�1

04

[36]

(con

tinu

ed)


Tab

le3.

2(c

onti

nued

)

Star

ting

reag

ents

Met

alca

rbox

ylat

esA

cids

Met

alco

mpo

unds

Rea

ctio

nco

ndit

ions

The

char

acte

rist

ics

Ref

.

Cu.

OO

CC

HD

CH

CO

OH

/ 2�4H

2O

Mal

A(C

uOH

) 2C

O3

orC

u(O

H) 2

H2O

solu

tion

ofth

eal

A(<

0ı

C,i

ce–

sali

neba

th)

IR:1

,660

,1,7

00,

835

cm�

1;

�ef

fD

1:9

7�

B(2

98K

)

[46]

Cu.

OC

OC

HD

CH

OC

O/

FAC

u 2(O

H) 2

CO

3M

etha

nol,

boil

ing

3h,

pH3–

4[3

]

Oth

ersa

lts

Li.

CH

3C

HD

CH

�C

HD

CH

CO

O/

Sorb

ite

acid

LiO

HH

otH

2O

,pH

D8

1H

-NM

R:ı

D1:6

(d,6

-H),

5.6

(d,

2-H

),6.

0(m

,4-

H,5

-H),

6.8

(dd,

3-H

)

[11]

Ca.

CH

2D

CH

CH

2C

OO

/ 2�

H2O

3-bu

teno

icac

idC

aCO

3H

2O

,3h

IR:3

,448

,3,0

81,

2,98

7,1,

582,

1,54

7,98

3,91

2cm

�1;

1H

-NM

R:

ıD

5:9

4(1

H,

ddt,

JD

14:2

,10

.2,7

.0H

z),

5.13

(1H

,br

d,J

D14:2

Hz)

,5.

10(1

H,b

rd,

JD

10:2

Hz)

,2.

97(b

rd,

2H,

JD

7:0

Hz)

[12]

(con

tinu

ed)


Tab

le3.

2(c

onti

nued

)

Star

ting

reag

ents

Met

alca

rbox

ylat

esA

cids

Met

alco

mpo

unds

Rea

ctio

nco

ndit

ions

The

char

acte

rist

ics

Ref

.

Inte

ract

ion

ofac

etat

ean

dot

her

salt

sw

ith

unsa

tura

ted

carb

oxyl

acid

sM

etal

(met

h)ac

ryla

tes

Tb.

OO

CC

HD

CH

2/.

OC

.CH

3/

DC

HO

CO

C2H

5/ 2

AA

Tb(

NO

3/ 3

�5H2O

Eth

anol

,et

hyla

ceto

acet

ate,

N2;

40

ıC

,48

h

[47]

Fe.O

OC

CH

DC

H2/.

OC

.CH

3/

DC

HO

CO

C2H

5/ 2

AA

FeC

l 3E

than

ol,

ethy

lace

toac

etat

e,N

2;

40

ıC

,48

h

[47]

Ni.

OO

CC

HD

CH

2/.

OC

.CH

3/

DC

HO

CO

C2H

5/

AA

NiC

l 2E

than

ol,

ethy

lace

toac

etat

e,N

2;

40

ıC

,48

h

[47]

Mn.

OO

CC

HD

CH

2/.

OC

.CH

3/

DC

HO

CO

C2H

5/

AA

MnC

l 2E

than

ol,

ethy

lace

toac

etat

e,N

2,4

0ı

C,4

8h

[47]

Mn 1

2O

12(C

H2C

(CH

3/

CO

O) 1

6(H

2O

) 4M

AA

Mn 1

2O

12(C

H3C

OO

) 16(H

2O

) 42

CH

3C

OO

H�4H

2O

Tolu

ene

susp

ensi

on,2

h,pr

ecip

itat

ion

hexa

ne:C

H2C

l 2

IR:1

,635

,1,5

60,

1,41

9,94

1,62

6cm

�1;y

ield

65%

[49]

Mn 1

2O

12(C

H2C

HC

OO

) 16

AA

Mn 1

2O

12(C

H3C

OO

) 16(H

2O

) 42

CH

3C

OO

H�4H

2O

Tolu

ene

susp

ensi

on,2

hC

12h,

prec

ipit

atio

nhe

xane

IR:1

,630

,1,5

50,

1,44

1,1,

372,

981,

625

cm�

1;

yiel

d89

%

[48]

Met

aldi

carb

oxyl

ates

Cu 2

.O2C

CH

DC

HC

O2/

FAC

u(C

H3C

O2/ 2

�H 2O

H2O

,aut

ocla

ve,1

50

ıC

,1.

5da

ys,p

HD

2–4

FTIR

:3,0

47,1

,521

,1,

388,

1,35

3,1,

212,

1,19

4,77

6,71

1;�

D3:2

4g

cm�

3

[52]

(con

tinu

ed)


Tab

le3.

2(c

onti

nued

)

Star

ting

reag

ents

Met

alca

rbox

ylat

esA

cids

Met

alco

mpo

unds

Rea

ctio

nco

ndit

ions

The

char

acte

rist

ics

Ref

.

Cu.

O2C

CH

DC

HC

O2/�H

2O

Mal

AC

uSO

4�5H

2O

,N

a 2C

O3�10

H2O

H2O

solu

tion

s,cr

ysta

lliz

atio

nIR

:1,6

65,1

,620

,854

,83

8cm

�1;

�ef

fD

2:0

0�

B(2

98K

)

[45,

46]

ŒCu 2

.O2C

CH

DC

HC

O2H

/ 4��

HO

OC

CH

DC

HC

OO

H�

4C

2H

5O

H

MA

CuS

O4�5H

2O

,N

a 2C

O3�10

H2O

Eth

anol

,boi

ling

2h,

crys

tall

izat

ion

IR:1

,715

,1,6

60-1

,620

,86

3,83

8,82

2cm

�1;

�ef

fD

1:1

2�

B(2

98K

)

[46]

Zn.

O2C

CH

DC

HC

O2/�H

2O

Mal

AZ

nSO

4�7H

2O

,N

a 2C

O3�10

H2O

H2O

susp

ensi

on,

crys

tall

izat

ion

[44]

ZnH

.OO

CC

HD

CH

CO

O/.

OH

/�

H2O

Mal

AZ

nCl 2

,NH

4O

HH

2O

solu

tion

s,ne

utra

lize

dac

id[1

3]

Cu.

O2C

CH

DC

HC

O2H

/�H2O

Mal

eic

anhy

drid

eC

uCl

H2O

solu

tion

,cr

ysta

lliz

atio

n[4

]

Oth

ersa

lts

Zn.

O2C

C6H

3.O

�.C

H2/ 1

1�

OC

OC

HD

CH

2

3,4-

Bis

(11-

acry

loyl

oxy-

unde

cano

xy)b

enzo

icac

id

NaO

H,Z

nSO

4�6H

2O

H2O

solu

tion

,st

irri

ng2

h,ex

trac

tion

wit

hch

loro

form

�as

.CO

O/

D1;5

59

cm�

1;

�s.

CO

O/

D1;4

33

cm�

1,

1H

-NM

R:

OC

OC

HD

CH

2

5.77

,6.1

0,6.

37(6

H,

AB

X);

13C

NM

R:

ıD

OC

OC

HD

CH

212

8.60

,130

.16,

166.

17

[76]

(con

tinu

ed)


Tab

le3.

2(c

onti

nued

)

Star

ting

reag

ents

Met

alca

rbox

ylat

esA

cids

Met

alco

mpo

unds

Rea

ctio

nco

ndit

ions

The

char

acte

rist

ics

Ref

.

Mg.

O2C

C6H

3.O

�.C

H2/ 1

1�

OC

OC

HD

CH

2/ 2

/ 2

3,4-

Bis

(11-

acry

loyl

oxyu

ndec

anox

y)be

nzoi

cac

id

NaO

H,M

gCl 2

�6H2O

H2O

-eth

anol

solu

tion

,ha

rdst

irri

ng2

h,ex

trac

tion

wit

het

her

�as

.CO

O/

D1;5

58

cm�

1;

�s.

CO

O/

D1;4

34

cm�

1,

1H

-NM

R:

OC

OC

HD

CH

2

5.77

,6.0

8,6.

40(3

H,A

BX

);13C

NM

R:

ıD

OC

OC

HD

CH

212

8.57

,13

0.25

,166

.22

[76]

Mg.

O2C

.CH

2/ 1

1�

OC

OC

HD

CH

2/ 2

�2H2O

12-A

cryl

oylo

xydo

deca

noic

acid

,.H

O2C

.CH

2/ 1

1O

CO

CH

DC

H2/

NaO

H,M

gCl 2

�6H2O

H2O

solu

tion

s,ha

rdst

irri

ng30

min

,re

crys

tall

izat

ion

inhe

ptan

e

�as

.CO

O/

D1;5

88

cm�

1;

�s.

CO

O/

D1;4

10

cm�

1,

1H

-NM

R:

OC

OC

HD

CH

2

5.77

,6.0

4,6.

36(3

H,A

BX

);13C

NM

R:

ıD

OC

OC

HD

CH

212

8.56

,13

0.20

,166

.37;

CO

O17

8.80

[76]

Lig

and

exch

ange

reac

tion

s.C

5H

5/ 2

Ti.

OC

OC

.CH

3/

DC

H2/ 2

(C5H

5/ 2

TiC

l 2Po

tass

ium

met

hacr

ylat

eC

hlor

ofor

m,s

tirr

ing,

60–7

0ı

C,3

hM

.m.3

47.1

(cry

osco

py;

benz

ene)

[63]

(con

tinu

ed)


Tab

le3.

2(c

onti

nued

)

Star

ting

reag

ents

Met

alca

rbox

ylat

esA

cids

Met

alco

mpo

unds

Rea

ctio

nco

ndit

ions

The

char

acte

rist

ics

Ref

.

.C5H

5/ 2

Ti.

OO

CR

/RD

�CH

DC

H�,

cis-

,mal

eate

anio

n;tr

ans-

,fu

mar

ate

anio

n

(C5H

5/ 2

TiC

lSo

dium

mal

eate

orfu

mar

ate

H2O

solu

tion

,Shl

enk

vess

elIR

:595

,790

,860

,1,

010,

1,12

0,1,

460,

3,10

5,41

40cm

�1

(mal

eate

);59

0,79

5,84

0,1,

010,

1,12

0,1,

450,

3,10

0cm

�1

(fum

arat

e);

�ef

fD

1:6

1

(mal

eate

),1.

68(f

umar

ate)

�B

(298

K),

�D

16;7

00,

13,9

00,1

0,20

0(m

alea

te);

17,5

00,1

3,50

0,10

,500

(fum

arat

e)cm

�1;

m.p

.290

–300

(dec

)(m

alea

te);

260–

262

(dec

)(f

umar

ate)

[65,

66]

Œ.C

5H

5/ 2

Ti.

OO

CC

HD

CH

CO

O/ 2

(C5H

5/ 2

TiC

l 2M

alei

cac

idH

2O

IR:1

,715

,1,6

40,

1,53

0,1,

310

cm�

1

[69]

Œ.C

5H

5/ 2

Ti.

�-O

CO

C�

CO

CO

/�2

(C5H

5/ 2

TiC

l 2A

DA

H2O

-chl

orof

orm

,20

ıC

,cr

ysta

lliz

atio

n[6

7]

(con

tinu

ed)


Tab

le3.

2(c

onti

nued

)

Star

ting

reag

ents

Met

alca

rbox

ylat

esA

cids

Met

alco

mpo

unds

Rea

ctio

nco

ndit

ions

The

char

acte

rist

ics

Ref

.

Ti.

OR

/ 3O

CO

C.C

H3/

DC

H2

RD

t-C

4H

9,i

-C3H

7,

t-am

yl,2

-eth

ylhe

xyl

Ti(

OR

) 4M

AA

No

solv

ent,

50–5

5ı

C,

110–

150

mm

Hg

�as

.CO

O/

D1;5

16–1

;588

cm�

1;

�s.

CO

O/

D1;4

23–1

;525

cm�

1;

�.T

i�O

/D

553–6

68

cm�

1

[71]

Eu.

TTA

/ 2.C

H2

DC

HC

OO

/TTA

-the

noyl

tri-

fluor

oace

tone

Eu(

Oi P

r)3

AA

,TTA

2-pr

opan

ol:b

enze

ne(1

:1),

4.5

h,bo

ilin

gFT

IR:1

,613

,1,5

82,1

,543

,1,

512,

1,45

8,1,

412,

1,35

7,93

5cm

�1;

UV

-vis

:313

,332

nm;

Mp

>250

ıC

[75]

Eu.

acac

/ 2.C

H2

DC

HC

OO

/Aca

c–

acet

ylac

eton

e

Eu(

Oi Pr

) 3A

A,a

cac

2-pr

opan

ol:b

enze

ne(1

:1),

4.5

h,bo

ilin

gFT

IR:1

,589

,1,5

22,1

,437

,1,

385,

922

cm�

1;

UV

-vis

:297

nm;

Mp

>250

ıC

[75]

Eu.

BA

/ 2.C

H2

DC

HC

OO

/BA

–be

nzoy

lace

tone

Eu(

Oi P

r)3

AA

,BA

2-pr

opan

ol:b

enze

ne(1

:1),

4.5

h,bo

ilin

gFT

IR:1

,595

,1,5

58,1

,531

,1,

487,

1,45

2,1,

387,

962

cm�

1;U

V-v

is:3

11,

336

sh,n

m;

Mp

>250

ıC

[75]

(con

tinu

ed)


Tab

le3.

2(c

onti

nued

)

Star

ting

reag

ents

Met

alca

rbox

ylat

esA

cids

Met

alco

mpo

unds

Rea

ctio

nco

ndit

ions

The

char

acte

rist

ics

Ref

.

Eu.

DB

M/ 2

.CH

2D

CH

CO

O/D

BM

–di

benz

oyla

ceto

ne

Eu(

Oi Pr

) 3A

A,D

BM

2-pr

opan

ol:b

enze

ne(1

:1),

4.5

h,bo

ilin

gFT

IR:1

,597

,1,5

52,

1,52

2,1,

479,

1,45

6,1,

442,

941

cm�

1;

UV

-vis

:316

,341

sh,n

m;M

p>

250

ıC

[75]

ŒCuL

a.O

CO

C.C

H3/

DC

H2/ 5

.phe

n/.C

2H

5O

H/�

2

Cu(

NO

3/ 2

�3H2O

La.

OC

OC

.CH

3/

DC

H2/ 3

�2H2O

H2O

-eth

anol

solu

tion

,pH

D4.

1;cr

ysta

lliz

atio

n�

as.C

OO

/D

1;5

50

cm�

1;

�s.

CO

O/

D1;4

19

cm�

1;

�.C

DC

/D

1648

cm�

1I�

eff

D1:9

5�

B

[80]

ŒCo 2

M.O

CO

CH

DC

HC

H3/ 6

.C9H

7N

/ 2�M

DM

n,M

g

Mn

and

Mg

crot

onat

esH

2O

,boi

ling

,3–4

h,cr

ysta

lliz

atio

n�

as.C

OO

/D

1;5

30,

1,57

2(M

n),

1,54

6,15

92cm

�1

(Mg)

�s.

CO

O/

D1;4

01

(Mn)

,1,

400

cm�

1

(Mg)

;�

max

D525,5

50,

574

(Mg)

,526

,55

5,58

0nm

(Mn)

[85]

(con

tinu

ed)


Tab

le3.

2(c

onti

nued

)

Star

ting

reag

ents

Met

alca

rbox

ylat

esA

cids

Met

alco

mpo

unds

Rea

ctio

nco

ndit

ions

The

char

acte

rist

ics

Ref

.

Eu.

OO

CC

HD

CH

C6H

5/�2

(phe

n)ph

en–

1,10

-phe

nant

roli

ne

Eu(

NO

3/ 3

�6H2O

NaO

OC

CH

DC

HC

6H

5H

2O

,eth

anol

,pH

D6–

7,yi

eld

82–9

0%m

pD

220

ıC

[80]

Eu.

OO

CC

HD

CH

C6H

5/�2

(dip

y)E

u(N

O3/ 3

�6H2O

NaO

OC

CH

DC

HC

6H

5H

2O

,eth

anol

,pH

D6–

7,yi

eld

82–9

0%m

pD

227

ıC

[80]

dipy

–2,

20-d

ipyr

idil

eE

u.O

OC

CH

DC

HC

6H

5/�2

(bta

)bt

a–b

enze

netr

iazo

le

Eu(

NO

3/ 3

�6H2O

NaO

OC

CH

DC

HC

6H

5H

2O

,eth

anol

,pH

D6–

7,yi

eld

82–9

0%m

pD

215

ıC

[80]

Eu.

OO

CC

HD

CH

C6H

5/�2

(tph

pho)

�2H2O

Eu(

NO

3/ 3

�6H2O

NaO

OC

CH

DC

HC

6H

5H

2O

,eth

anol

,pH

D6–

7,yi

eld

82–9

0%m

pD

218

ıC

[80]

Tph

pho-

trip

heny

lpho

sphi

neox

ide

Tb.

OO

CC

HD

CH

C6H

5/�H

2O

Tb(

NO

3/ 3

�6H2O

NaO

OC

CH

DC

HC

6H

5H

2O

,eth

anol

,pH

D6–

7,yi

eld

82–9

0%m

pD

290

ıC

[80]

Oth

erre

acti

ons

.C6H

5/ 4

SbO

CO

CH

DC

HC

OO

HM

alA

(C6H

5/ 5

SbB

enze

ne-d

ioxi

ne(5

:1),

24h,

20

ıC

�.C

DO

/D

1700,

1620

cm�

1,m

.p.

165

ıC

,yie

ld87

%

[112

]

.C6H

5/ 4

SbO

CO

CH

DC

HO

CO

Sb.C

6H

5/ 4

Mal

A(C

6H

5/ 5

Sb1:

2(m

ol),

diox

ine,

60

ıC

�.C

DO

/D

1640,

1620

cm�

1,m

.p.

232

ıC

(dec

),yi

eld

99%

[112

]

(con

tinu

ed)


Tab

le3.

2(c

onti

nued

)St

arti

ngre

agen

tsM

etal

carb

oxyl

ates

Aci

dsM

etal

com

poun

dsR

eact

ion

cond

itio

nsT

hech

arac

teri

stic

sR

ef.

.CH

3/ 3

SnO

CO

CH

DC

HO

CO

Sn.C

H3/ 3

Mal

eic

anhy

drid

e(C

H3/ 3

SnO

HB

enze

ne,6

h,80

ıC

,re

crys

tall

izat

ion

wit

hac

eton

e

Yie

ld82

%[1

13]

.C6H

5/ 2

Pb.O

CO

CH

DC

HO

CO

/

Mal

eic

anhy

drid

e(C

6H

5/ 3

PbO

HB

enze

ne,4

h,80

ıC

Yie

ld70

%[1

13]

ŒfFe.

sale

n/g 2.

OO

CC

�C

CO

O/�

sale

nH2

–N

;N0 -b

is(s

alic

ylid

ene)

ethy

lene

diam

ine

Ace

tyle

nedi

carb

oxyl

icac

id[fF

e(sa

len)

g 2]B

uOH

,boi

ling

3h

IR:2

,084

,1,6

26,

1,59

6,1,

542,

1,44

0,1,

382,

968

cm�

1

[111

]

ŒfFe.

salo

ph/g 2

.OO

CC

�C

CO

O/�

salo

phH

2–

N;N

0 -bis

(sal

icyl

iden

e)-o

-ph

enyl

ened

iam

ine

[fFe(

salo

ph)g 2

]B

uOH

,boi

ling

3h

IR:1

,632

,1,6

04,

1,57

8,1,

552,

1,53

4,1,

440,

1,37

2,92

0cm

�1

[111

]


References

1. J.R. Allan, G.M. Baillie, J.G. Bonner, D.L. Gerrard, S. Hoey, Thermochim. Acta. 143,283 (1989)

2. J.R. Allan, G.M. Baillie, J.G. Bonner, Eur. Polym. J. 26, 963 (1990)3. Y.Y. Wang, X. Wang, Q.Z. Shi: Trans. Metal Chem. 27, 481 (2002)4. P.Yu. Zavalii, M.G. Mys’kiv, E.I. Gladyshevskii, Crystallography 30, 688 (1985)5. V.V. Oleinik, M.G. Mys’kiv, Zh. Neorg. Khim. 41, 398 (1996)6. R. Baggio, B. Foxman, M.T. Garland, M. Perec, W. Shang, Acta Cryst. C. 56, e505 (2000)7. M. Badea, R. Olar, D. Marinescu, G. Vasile, J. Therm. Anal. Calorim. 80, 683 (2005)8. B.S. Randhawa, M. Kaur, J. Therm. Anal. Calorim. 89, 251 (2007)9. P.-Y. Jiang, Z.-C. Zhang, M.-W. Zhang, J. Polym. Sci. A Polym. Chem. 34, 695 (1996)

10. E.S. Rufino, E.E.C. Monteiro, Polymer 41, 4213 (2000)11. S.M. Schlitter, H.P. Beck, Chem. Ber. 129, 1561 (1996)12. M.J. Vela, B.B. Snider, B.M. Foxman, Chem. Mater. 10, 3167 (1998)13. I. Vancso-Szmercsanyi, A. Kallo, J. Polym. Sci. A Polym. Chem. 20, 639 (1982)14. A.D. Pomogailo, V.S. Savostyanov, Synthesis and Polymerization of Metal-Containing

Monomers (CRC, Boca Raton, 1994)15. Pat. 84660, Roumania, 198416. F. Santiango, A.E. Mucientes, M. Osorio, C. Rivera, Eur. Polym. J. 43, 1 (2007)17. Pat. 94753, Poland, 197718. Appl. 60–20833, Japan, 198519. Appl. 2218639 and 60–92238, Japan, 198520. Z. Woitczak, A. Gronowskii, Polimery. 27, 471 (1982)21. G.I. Dzhardimalieva, A.D. Pomogailo, V.I. Ponomarev, L.O. Atovmyan, Yu M. Shulga,

A.G. Starikov, Izv. Akad. Nauk SSSR, Ser. Khim. 1525 (1988)22. Yu M. Shulga, O.S. Roshchupkina, G.I. Dzhardimalieva, I.V. Chernushevich, A.F. Dodonov,

Yu. V. Baldokhin, P.Ya. Kolotyrkin, A.S. Rozenberg, A.D. Pomogailo, Izv. Akad. Nauk SSSR,Ser. Khim. 1739 (1993)

23. Yu M. Shulga, I.V. Chernushevich, G.I. Dzhardimalieva, O.S. Roshchupkina, A.F. Dodonov,A.D. Pomogailo, Izv. Akad. Nauk SSSR, Ser. Khim. 1047 (1994)

24. Y. Wang, Q. Shi, B. Yang, Q. Z. Shi, Y. Gao, Z. Zhou, Sci. China B 42, 363 (1999)25. W. Kuchen, J. Schram, Angew. Chem. Int. Ed. Engl. 27, 1695 (1988)26. F. Urena-Munez, P. Diaz-Jimenez, C. Barrera-Diaz, M. Romero-Romo, M. Palomar-Pardave,

Radiat. Phys. Chem. 68, 819 (2003)27. S.M. Sayyah, A.A. Bahgat, A.I. Sabby, F.I.A. Said, S.H. El-Hamouly, Acta Polym. 39,

399 (1988)28. M. Anand, A.K. Srivastava, Angew. Makromol. Chem. 219, 1 (1994)29. Z.H. Asadov, M. Nurbas, S. Kabasakai, M. Solener, S.M. Nasibova, A.D. Agazade, Iranian

Polym. J. 14, 597 (2005)30. M.A. Ghandour, E. Aboulkazim, J. Indian Chem. Soc. 61, 504 (1984)31. A.S. Simeu, A.F. Radchenko, G.E. Ermolina, A.K. Molodkin, Zh. Neorg. Khim. 33,

3107 (1988)32. A.S. Simeu, G.E. Ermolina, A.K. Molodkin, Zh. Neorg. Khim. 33, 1249 (1988)33. G.N. Makushova, B.L. Faifel, S.B. Pirkes, A.V. Lapitskaya, L.B. Bessudnova, Zh. Neorg.

Khim. 34, 628 (1989)34. L. Mu, V.Y. Young, N.B. Comerford, J. Chem. Eng. Data. 38, 481 (1993)35. D.A. Merkulov, V.I. Kornev, Zh. Neorg. Khim. 44, 439 (1999)36. T.A. Krasovskaya, S.B. Pirkers, A.S. Molotkov, Zh. Neorg. Khim. 29, 1964 (1984)37. J.E. Contreras, V. Belkis Ramirez, G. Diaz de Delgado, J. Chem. Crystallogr. 27, 391 (1997)38. A.V. Briceno, G. Diaz de Delgado, B.V. Ramirez, W.O. Velasquez, A.B. Bahsas, J. Chem.

Crystallogr. 29, 785 (1999)39. P.R. S. Sharma, R. Jagannathan, M. Vithal, J. Chem. Soc. Dalton Trans. 723 (1992)

References 53

40. A. Galvan-Sanchez, F. Urena-Nunez, H. Flores-Llamas, R. Lorez-Castanares, J. Appl. Polym.Sci. 74, 995 (1999)

41. M. Schmidt, A. Bauer, H. Schmidbaur, Inorg. Chem. 36, 2040 (1997)42. Ch.Y. Wong, J.D. Woolins, Coord. Chem. Rev. 130, 143 (1994)43. R.C. Mehrotra, R. Bohra, Metal Carboxylates (Academic Press, London, 1983)44. J.R. Allan, G.M. Baillie, J.G. Bonner, D.L. Gerrard, S. Hoey, Thermochim. Acta. 143,

283 (1989)45. J. Cernak, J. Chomic, Ch. Kappenstein, F. Robert, J. Chem. Soc. Dalton Trans. 2981 (1997)46. K. Gora, E. Kyuno, R. Tsuchiya, J. Bull. Chem. Soc. 41, 2624 (1968)47. S. Wu, Y. Wu, F. Zeng, Z. Tong, J. Zhao, Macromol. Rapid Commun. 27, 937 (2006)48. F. Palacio, P. Oliete, U. Schubert, I. Mijatovic, N. Husing, H. Peterlik, J. Mater. Chem. 14,

1873 (2004)49. S. Willemin, B. Donnadien, L. Lecren, B. Henner, R. Clerac, C. Guerin, A.V. Pokrovskii,

J. Larionova, New J. Chem. 28, 919 (2004)50. R. Cusnir, G. Dzhardimalieva, S. Shova, D. Prodius, N. Golubeva, A. Pomogailo, C. Turta, in

Int. Conf. on Coord. Chemistry-ICCC38, Jerusalem, Israel, 20–25 July. 2008, p. 47551. V.V. Skopenko, A.Yu. Tsivadze, L.I. Saranskii, A.D. Garnovskii, Kordinatsionnaya khimiya

(Publ.Center “Akademkniga”, Moscow, 2007)52. D.M. Young, U. Geiser, A.J. Schultz, H. Hau Wang: J. Am. Chem. Soc. 120, 1331 (1998)53. P.M. Forster, A.R. Burbank, C. Livage, G. Ferey, A.K. Cheetham, Chem. Commun.

368 (2004)54. W.-H. Zhu, Z.-M. Wang, S. Gao, Dalton Trans. 765 (2006)55. X. Li, Y.-Q. Zou, J. Chem. Crystallogr. 35, 351 (2005)56. A. Michaelides, S. Skoulika, E.G. Bakalbassis, J. Mrozinski, Cryst. Growth Des. 3, 487

(2003)57. J. Tao, M.-L. Tong, J.-X. Shi, X.-M. Chen, S.W. Ng, Chem. Commun. 2043 (2000)58. V.T. Panyushkin, A.A. Mastakov, N.N. Bukov, Zh. Neorg. Khim. 28, 2779 (1983)59. V.T. Panyushkin, N.V. Achrimenko, A.S. Khachatrian, Polyhedron 17(18), 3053–3058 (1998)60. V.T. Panyushkin, Koord. Khim. 21, 747 (1995)61. T.P. Storozhenko, V.T. Panyushkin, Zh. Neorg. Khim. 35, 2396 (1990)62. T. Shi, L.I. Elding, Inorg. Chem. 37, 5544 (1998)63. A.N. Nesmeyanov, O.V. Nogina, A.M. Berlin, A.S. Girshovich, G.V. Shatalov, Izv. Akad.

Nauk SSSR, Otd. Khim. Nauk. 2146 (1961)64. R. Ralea, G. Ungurenasu, I. Maxim, Rev. Roum. Chim. 12, 523 (1967)65. R.S.P. Coutts, P.C. Wailes, Aust. J. Chem. 20, 1579 (1967)66. L.C. Francesconi, D.R. Corbin, A.W. Clauss, D.N. Hendrickson, G.D. Stucky, Inorg. Chem.

20, 2078 (1981)67. T. Guthner, U. Thewalt, J. Organomet. Chem. 350, 235 (1988)68. H.-P. Klein, K. Doppert, U. Thewalt, J. Organomet. Chem. 280, 203 (1985)69. K. Doppert, R. Sanchez-Delgado, H.-P. Klein, U. Thewalt, J. Organomet. Chem. 233,

205 (1982)70. Yu. G. Yatluk, A.L. Suvorov, Zh. Prikl. Khim. 58, 1824 (1985)71. M. Camail, M. Humbert, A. Margaillan, A. Riondel, J.L. Vernet, Polymer 39, 6525 (1998)72. A.B. Burdin, A.L. Suvorov, V.V. Sennikov, Plast. Massy. 27 (2003)73. Yu. G. Yatluk, S.V. Chernyak, A.L. Suvorov, E.A. Abramova, Zh. Obshch. Khim. 71,

965 (2001)74. Q.D. Ling, Q.J. Cai, E.T. Kang, K.G. Neoh, F.R. Zhu, W. Huang, J. Mater. Chem. 14,

2741 (2004)75. L.-H. Wang, W. Wang, W.-G. Zhang, E.-T. Kang, W. Huang, Chem. Mater. 12, 2212 (2000)76. L. Marcot, P. Maldivi, J.-C. Marchon, D. Guillon, M. Ibn-Elhaj, Chem. Mater. 9, 2051 (1997)77. H.-L. Wu, Y.-C. Gao, J. Coord. Chem. 59, 137 (2006)78. Z. Shi, L. Zhang, S. Gao, G. Yang, J. Hua, L. Gao, S. Feng, Inorg. Chem. 39, 1990 (2000)79. P.S. Mukherjee, T.K. Maji, G. Mostafa, J. Ribas, M.S. El Fallah, N.R. Chaudhuri, Inorg.

Chem. 40, 928 (2001)


80. I.V. Kalinovskaya, V.E. Karasev, A.N. Zadorozhnaya, L.I. Lifar, Koordinats. Khim. 27,551 (2001)

81. G.I. Dzhardimalieva, I.N. Ivleva, Yu. M. Shulga, E.N. Frolov, A.D. Pomogailo, Izv. Akad.Nauk, Ser. Khim. 1145 (1998)

82. B. Wu, W.-M. Lu, X.-M. Zheng, Chin. J. Chem. 20, 846 (2002)83. B. Wu, W.-M. Lu, X.-M. Zheng, J. Coord. Chem. 55, 497 (2002)84. B. Wu, Y. Guo, Acta Crystalogr. E 60, m1356 (2004)85. W. Clegg, P.A. Hunt, B.P. Straughan, J. Chem. Soc. Dalton Trans. 1127 (1989)86. A.D. Pomogailo, Russ. Chem. Rev. 69, 60 (2000)87. A.D. Pomogailo, Kolloid. Zh. 67, 726 (2005)88. G. Kickelbick, U. Schubert, Chem. Ber. 130, 473 (1997)89. S. Gross, G. Kickelbick, M. Puchberger, U. Schubert, Monatsh. Chem. 134, 1053 (2003)90. B. Moraru, G. Kickelbick, M. Battistella, U. Schubert, J. Organomet. Chem. 636, 172 (2001)91. G. Kickelbick, U. Schubert, Chem. Ber./Recueil. 130, 473 (1997)92. G. Kickelbick, P. Wiede, U. Schubert, Inorg. Chim. Acta 284, 1 (1999)93. M. Puchberger, F.R. Kogler, M. Jupa, S. Gross, H. Fric, G. Kickelbick, U. Schubert,

Eur. J. Inorg. Chem. 3283 (2006)94. F.R. Kogler, M. Jupa, M. Puchberger, U. Schubert, J. Mater. Chem. 14, 3133 (2004)95. Ch. Barglik-Chory, U. Schubert, J. Sol-Gel Sci. Technol. 5, 135 (1995)96. U. Gbureck, J. Probst, R. Thull, J. Sol-Gel Sci. Technol. 27, 157 (2003)97. C. Sanches, M. In, J. Non-Cryst. Solids 147/148, 1 (1992)98. E. Martinez-Ferrero, K. Boubekeur, F. Ribot, Eur. J. Inorg. Chem. 802 (2006)99. U. Schubert, E. Arpac, W. Glaubitt, A. Helmerich, C. Chau, Chem. Mater. 4, 291 (1992)

100. G. Kickelbick, U. Schubert, Eur. J. Inorg. Chem. 159 (1998)101. H. Fric, M. Jupa, U. Schubert, Monatsh. Chem. 137, 1 (2006)102. M. Jupa, G. Kickelbick, U. Schubert, Eur. J. Inorg. Chem. 1835 (2004)103. B. Moraru, G. Kickelbick, U. Schubert, Eur. J. Inorg. Chem. 1295 (2001)104. J. Mendezz-Vivar, P. Bosch, V.H. Lara, J. Non-Cryst. Solids 351, 1949 (2005)105. A. Albinati, F. Faccini, S. Gross, G. Kickelbick, S. Rizzato, A. Venzo, Inorg. Chem. 46,

3459 (2007)106. B. Moraru, G. Kickelbick, U. Schubert, Eur. J. Inorg. Chem. 1295 (2001)107. J. Novrocik, J. Pecha, M. Novrocikova, Czech. P., Zh. Khim. 11, 53 (1988)108. K.M. Khurshid Alam, F. M. Kaniz, A. Gulzar, Pak. J. Sci. Ind. Res. 707 (1987)109. H. Billetter, I. Pantenburg, U. Ruschewitz, Acta Crystallogr. E 62, m 881 (2006)110. H. Billetter, I. Pantenburg, U. Ruschewitz, Acta Crystallogr. E 61, m1857 (2005)111. P. Kopel, Z. Sindelar, R. Klicka, Trans. Met. Chem. 23, 139 (1998)112. V.V. Sharutin, O.K. Sharutina, A.P. Pakusina, V.K. Belsky, J. Organomet. Chem. 536–537,

87 (1997)113. V. F. Mishchenko, Z.M. Rzaev, V.A. Zubov, Biostable Tin-Containing Polymers (Khimiya,

Moscow, 1995)114. M. Kamal, A.K. Srivastava, React. Funct. Polym. 49, 55 (2001)115. M. Kamal, A.K. Srivastava: Polym. Plast. Technol. Eng. 40, 293 (2001)116. A.V. Gushchin, V.A. Dodonov, in Fundamental Problems of Polymer Science. Int. Conf.,

21–23 January 1997 (Moscow, 1997), pp. 1–21117. M.J. Moloney, B.M. Foxman, Inorg. Chim. Acta 229, 323 (1995)118. J. Blenkers, H.J. De Liefde Meijer, J.H. Teuben, J. Organomet. Chem. 218, 383 (1981)119. E. Klei, J.H. Teuben, H.J. De Liefde Meijer, J. Organomet. Chem. 224, 327 (1982)120. G. Schubert, I. Papai, J. Am. Chem. Soc. 125, 14847 (2003)121. I. Papai, G. Schubert, I. Mayer, G. Besenyei, M. Aresta, Organometallics, 23, 5252 (2004)122. R. Fischer, J. Langer, A. Malassa, D. Walther, H. Gorls, G. Vaughan, Chem. Commun.

2510 (2006)123. A. Galinda, A. Pastor, P.J. Perez, E. Carmona, Organometallics 12, 4443 (1993)124. C. Collazo, M. Der Mar Conejo, A. Pastor, A. Galindo, Inorg. Chim. Acta 272, 125 (1998)125. M. Aresta, C. Pastore, P. Giannoccaro, G. Kovacs, A. Dibenedetto, I. Papai, Chem. Eur. J. 13,

9028 (2007)

References 55

126. V.A. Maksakov, V.P. Kirin, S.N. Konchenko, N.M. Bravaya, A.D. Pomogailo, A.V. Virovets,N.V. Podberezskaya, I.G. baranovskaya, S.V. Tkachev, Izv. Akad. Nauk. 1293 (1993)

127. N.M. Bravaya, A.D. Pomogailo, in Metal-Containing Polymeric Materials, ed. byC.U. Pittman Jr., C.E. Carraher Jr., M. Zeldin, B. Culberston (Plenum Publ. Corp., New York,1996), p.51

128. N.D. Golubeva, O.A. Adamenko, G.N. Boiko, A.D. Pomogailo, Inorg. Mater. 40, 363 (2004)129. O.A. Adamenko, G.V. Lukova, N.D. Golubeva, V.A. Smirnov, G.N. Boiko, A.D. Pomogailo,

I.E. Uflyand, Dokl. Phys. Chem. 381, 360 (2001)130. N.D. Golubeva, S.I. Pomogailo, G.N. Boiko, L.A. Petrova, Yu.A. Olkhov, A.D. Pomogailo,

in Polymers-2004. Proceed. 3 Russ. Kargin Conf. (Moscow State University, Moscow, 2004),p. 138

131. A.D. Pomogailo, A.S. Rozenberg, I.E. Uflyand, Metal Nanoparticles in Polymers (Khimiya,Moscow, 2000)

132. J.H. O’Donnell, R.D. Sothman, Radiat. Phys. Chem. 13, 77 (1979)133. M.L. Post, J. Trotter, J. Chem. Soc. Dalton Trans. 674 (1974)134. A. Hempel, S.E. Hull, Raja Ram, M.P. Gupta, Acta Cryst. B 35, 2215 (1979)

Chapter 4Spectral Characteristics and MolecularStructure of Unsaturated Carboxylic Acid Salts

In most typical cases the carboxylate group RCOO� is capable of coordinatingwith metals such as monodentate (syn- and anti- configuration) (I), bidentate-cyclic (chelate) (II), bidentate-bridging (III), tridentate (IV), and tetradentate (V)ligands [1–3]:

C

R

M

O O

C

R

M

O O

anti synI

C

R

MO O

II

C

R

M

O O

III

M

C

R

M

O O

IV

M

M C

R

M

O O

V

M

MM

CO

O

CHCHR

MVI

Oligomeric and polymeric coordination complexes with one, two, three, or fourcarboxylate bridges between each pair of metal atoms are known among experimen-tally proven structures.

Such a large diversity of possible structures and compositions for metal carboxy-lates can additionally include in the case of the unsaturated analogs, participation ofa multiple bond functionality that is known to be able to participate in metal atomcoordination via a formation of a -bond (VI). Therefore, there is an interest to an-alyze peculiarities of the geometry and the coordination type of metal carboxylatefragment in a series of unsaturated mono- and dicarboxylic acid anions.

4.1 Metal (Meth)acrylates

Various methods are employed for the structural studies of metal carboxy-lates. Vibrational, UV-, and visible spectroscopy, as well as magnetic- and”-resonance spectroscopic methods are widely used for getting stereochemical


57

58 4 Spectral Characteristics and Molecular Structure of Unsaturated Carboxylic Acid Salts

information regarding the coordination number, shape of the coordination polyhe-dron, coordination mode, and denticity of a carboxylate ligand. Diffraction methods,such as electronic, neutron, and X-ray diffraction allow full quantitative structuralinformation to be received. Also, quantum chemical calculation methods includingMO LCAO and density functional theory (DFT) are involved in the studies. The fol-lowing are examples of identification of spatial forms of the carboxylates of thistype based on the data from experimental methods.

4.1.1 IR Spectroscopy

Frequencies �as(COO�/ and �s(COO�/ corresponding to asymmetrical andsymmetrical vibrations of the carboxylate ion are the most characteristic in theIR spectra of metal carboxylates. Structures I–IV implies the presence of equivalentand unequivalent oxygen atoms in the carboxyl group, which is observed in the IRspectra. In monodentate complexes the difference ��.�as.COO�/ � �s.COO�// ismuch larger than the one for ionic compounds (164–171 cm�1/, while for bidentatecarboxylate complexes, the �� values are much smaller [2]. Thus, the binuclearCu(II) methacrylate Cu2[CH2DC(CH3)COO]4(H2O)2 in methanol is convertedinto a mononuclear complex upon replacement of the coordinated water by astronger donor ligand such as benzimidazole, and the bidentate coordination ofthe methacrylate ion becomes monodentate .�� D 203 cm�1/ [4]. Spectroscopicdata are in concert with the results of X-ray analysis. As in the majority of cases,the C�O bond for the coordinated oxygen atom is longer than the one for thenon-coordinated atom (see Table 4.1).

The structure of the carboxylate ligand is appreciably affected by steric fac-tors. Thus, trialkoxytitanium(IV) methacrylate complexes (CH2DC(CH3)�COO)Ti(OR)3 (where R D i -Pro, t-Bu, t-Am, 2-ethylhexyl) exist as equilibrium mix-tures of structures with bridging and cyclical bidentate coordination of methacrylategroup (Table 4.1) [5]:

Ti

RO

RO

RO

C

C

CH2H3C

CH2H3C

O O

Ti

C

C

O O

OR

OR

OR

CH2H3C

ROOR

OR

C

C

O O

Ti

Ti-I Ti-II

CH2

CH2

H3C

H3C

H3CH2C

Ti

RO

RO OR

CC

O

O

Ti

CC

O

O

RO

OR

OR

C

C

O O

RO

RO ROTi

Ti-III

4.1 Metal (Meth)acrylates 59

Tab

le4.

1St

ruct

ural

para

met

ers

ofR

CO

O

Coo

rdin

atio

nm

ode

Dis

tanc

e(A

)

Met

alca

rbox

ylat

e�

as(C

OO

)(c

m�

1)

�s(

CO

O)

(cm

�1)

��

(cm

�1)

C�O

coor

dC

�Ote

rmin

M�O

Ref

.

Cu 2

ŒCH

2DC

.CH

3/C

OO

� 4.H

2O

/ 21,

572

1,41

515

7II

I[4

]C

uŒC

H2DC

.CH

3/C

OO

� 2.C

7H

6N

2/ 2

1,56

41,

361

203

I1.

2620

(13)

1.24

52(1

3)1.

9752

(7)

[4]

Cu 2

ŒCH

2DC

.CH

3/C

OO

� 4.C

7H

6N2/ 2

1,58

31,

420

163

III

1.96

1,1.

994

[4]

Ti(

OB

u)3.C

H2DC

.CH

3/�

CO

O/

1,55

61,

424

132

III

[5]

Ti(

Oi-

Pro)

3.C

H2DC

.CH

3/�

CO

O/

1,56

1,1,

516

1,42

413

7,92

II,I

II[5

]T

i(O

-t-B

u)3.C

H2DC

.CH

3/�

CO

O/

1,58

8,1,

550,

1,52

51,

425

163,

125,

100

II,I

II[5

]

Ti(

O-t

-Am

) 3.C

H2DC

.CH

3/�

CO

O/

1,58

6,1,

554,

1,51

71,

423

163,

131,

94II

,III

[5]

Ti(

O-e

thyl

hexy

l)3.C

H2DC

.CH

3/�

CO

O/

1,55

6,1,

519

1,42

313

3,96

II,I

II[5

]

Cu 3

ŒCH

2DC

HC

OO

� 5.O

H/.

imH

/ 21,

570,

1,56

51,

418, 1,37

019

5,15

2I,

III

[6]

Cu 3

ŒCH

2DC

.CH

3/C

OO

� 5(O

H)

.im

H/ 2

1,57

5,1,

564

1,41

3, 1,36

519

9,16

2I,

III

1.97

51m

ono,

2.00

64m

ono,

1.99

88m

ono,

1.98

78bi

,2.

1476

bi,

1.94

57bi

5

[6]

ŒLa 2

.CH

2DC

.CH

3/C

OO

/ 6.p

hen/

2��2H

2O

II,I

II2.

498 b

r;av

,2.

606 c

h;av

[7]

ŒLa 2

.CH

2DC

.CH

3/C

OO

/ 6(p

hen)

2

.CH

2DC

.CH

3/C

OO

H/ 2

�

II,I

II2.

494 b

r;av

,2.

612 c

h;av

[8]

(con

tinu

ed)


Tab

le4.

1(c

onti

nued

)

Coo

rdin

atio

nm

ode

Dis

tanc

e(A

)

Met

alca

rbox

ylat

e�

as(C

OO

)(c

m�

1)

�s(

CO

O)

(cm

�1)

��

(cm

�1)

C�O

coor

dC

�Ote

rmin

M�O

Ref

.

ŒCuL

a.C

H2DC

.CH

3/C

OO

/ 5.p

hen/

.C2H

5O

H/�

2

1,55

01,

419

131

II,I

II2.

484 b

r,2.

582 c

h[9

]

ŒCoC

e..C

H2DC

.CH

3/C

OO

/ 5.p

hen/

.C2H

5O

H/�

2

1,54

91,

422

127

II,I

II2.

570(

3)ch

,2.5

29(3

) ch,

2.47

6(3)

br,

2.43

9(3)

br

[10]

ŒCuT

b.C

H2DC

.CH

3/C

OO

/ 5.p

hen/

.H2O

/�2

1,55

81,

427

131

II,I

II2.

455 c

h;av

,2.3

39br

;av

[11]

ŒLaZ

n 2.C

H2DC

.CH

3/C

OO

/ 6.N

O3/.

2,20

-bip

y/2�

1,56

71,

421

146

III

2.42

9(3)

br–

2.50

7(3)

br(L

a�O

),20

03(3

) br–

2.08

3(3)

br

(Zn�

O)

[12]

ŒPrZ

n 2.C

H2DC

.CH

3/C

OO

/ 6.N

O3/.

2,20

-bip

y/2�

1,57

41,

414

160

III

2.39

4(3)

br–

2.45

4(3)

br(P

r�O

),20

03(3

) br–

2.07

7(3)

br

(Zn�

O)

[13]

ŒNdZ

n 2.C

H2DC

.CH

3/C

OO

/ 6.N

O3/.

2,20

-bip

y/2�

1,57

41,

408

166

III

2.38

2(4)

br–

2.43

8(4)

br(N

d�O

),20

08(3

) br–

2.07

3(3)

br

(Zn�

O)

[14]

Ca.

CH

2DC

HC

H2C

OO

/ 2�H 2

O1,

582,

1,54

7II

,III

2.31

8(15

)–2.

356(

13) b

r,2.

5979

13)–

2.56

2(14

) ch

[15]

Li.

CH

2DC

.CH

3/�

CO

O/

1,57

21,

423

149

[16]

Na.

CH

2DC

.CH

3/�

CO

O/

1,55

81,

419

139

[16]


Meanwhile, tri(n-butoxy)titanium methacrylate containing less bulky n-butoxygroups forms dimer with titanium atoms linked by carboxyl and butoxy bridges.There are also terminal alkoxy groups in the structure:

Ti

BuOBuO

BuO

C

C

CH2H3C

CH2H3C

O O

Ti

C

C

O O

OBu

OBuOBu

Ti-IV

Formation of the four-membered rings upon chelate coordination of the car-boxylate group requires high strains in valence angles of the metal atom. Nosuch strain is present in the compounds of rare earth elements, and the possi-bility of bidentate cyclic coordination increases. Apparently, strain relief is fa-cilitated by the higher polarity of the metal–ligand bond and high coordinationnumbers of the metals. For example, the lanthanoid center in heteronuclear Cu2La2

[9, 17] or CoCe [10] methacrylate complexes bears both the bridging and chelatinggroups. Moreover, instances of the tridentate coordination of methacrylate groupsare not rare in this type of carboxylate complexes. In these cases one oxygenatom of the carboxyl group simultaneously forms bonds with two metal atoms.Metal atoms in isomorphic binuclear La or Gd trans-2,3 dimethacrylate complexes[M(OOC(CH3/C(CH3/CH)3(phen)]2 are connected by two bridging bidentate andtwo tridentate carboxylate groups [18]:

La

OOO

C

O

La

OO

C

OO

C

C

OO

C

OO

C

Binuclear methacrylate complexes [Gd2(CH2DC(CH3/COO)6(phen)2] � 2H2O[19],[La2(CH2DC(CH3/COO)6(phen)2] � 2H2O[7],and[La2(CH2DC(CH3/COO)6


(phen)2CH2DC(CH3/COOH)2] [8] possess the analogous structure. Similarly thestructure above the coordination environment of metal atoms in these complexeshas a configuration of a slightly distorted tricapped trigonal prism, while twobridging bidentate and two tridentate carboxylate groups connect the metal cen-ters. Tetranuclear zinc – cerium methacrylate complex [Zn2Ce2(CH2DC(CH3/

COO)10(bipy)2(H2O)2] also has a resembling structure [20]. Each Ce(III) ionis coordinated by nine oxygen atoms from one chelating and five bridging car-boxyl groups and a water molecule forming a tricapped trigonal prism. Thereare two tridentate bridging cyclical CH2DC(CH3/COO groups and three biden-tate bridging groups between the metal centers Ce�Ce and Ce�Zn, respectively.On the contrary, there are only bidentate bridging carboxylates in the struc-tures of isomorphic trinuclear [PrZn2(CH2DC(CH3/COO)6(NO3/(2,20-bipy)2][13], [NdZn2(CH2DC(CH3/COO)6(NO3/(2,20-bipy)2] [14], and [LaZn2(CH2D C(CH3/COO)6(NO3/(2,20-bipy)2] [12] complexes. IR spectroscopy data .�� D146–166 cm�1/ also supports this.

Note that the transition from the bridging to the cyclical coordination of theRCOO group results in elongation of the M�O bond (Table 4.1). Average bondlength for the Ln�Obridging, Ln�Ochelating, and Ln�Otridentate bonds are 2.473, 2.556,and 2.615 A in the La complex above, while the same bonds equal 2.365, 2.455, and2.530 A in the Gd complex [18]. This tendency is also observed for methacrylatecomplexes, [7, 8, 19] as well as for others [15]. Comparison of M�O distances inthe tridentate bridging cyclical group demonstrates that the bond M1�O2 is weakerthan two others.

C

O1 O2

M1 M2

For example, this distance equals 2.6385(15) A in comparison with theM1�O1 one (2.5674(18) A) in the molecule of the heteronuclear methacrylatecomplex ZnCe [20], the same distances in the complex [Gd2(CH2DC(CH3/

COO)6(phen)2] � 2H2O [19] being 2.644(3) and 2.456(3) A, respectively. It is note-worthy that the M2�O2 bond is often shorter than the M1�O1 one. That is thetridentate oxygen atom has the strongest bond with the metal, although this atomprovides part of its binding electron density to the second metal atom.

In turn, the higher charge density on the oxygen atom of the monodentate car-boxylate group in comparison with the bridging one, also causes the correspondingshortening of the M�O bond. This is evidenced, for example, by the structural datafor the trinuclear Cu(II) methacrylate [6], which has both monodentate and biden-tate bridging carboxylate groups. Average length of the Cu�Omonodentate bond equals1.9934 A that is shorter that the average length of the Cu�Obidentate one (2.0270 A).

It is notable that even in essentially ionic compounds, for example, in lithiumand sodium methacrylates [16], the �� values may deviate from those in purely


ionic salts, and the degree of covalence of the metal ion – ligand bond1 increases[21] (Table 4.1). As part of a general tendency, it may be related to the increase ofacceptor properties of the carboxylate ligand with the unsaturated fragment.

4.1.2 Magnetic Properties

Antiferromagnetic interactions play an important role in the studies of the nature ofthe metal–metal bond and the structure of metal carboxylates. The value of effectivemagnetic moments for a number of copper (meth)acrylates is 1.4 �B, which is muchlower than the purely spin value and is consistent with the dimeric structure of thecorresponding carboxylates (Table 4.2). The temperature dependence of the mag-netic susceptibility in these systems attests to strong antiferromagnetic exchangeinteraction of the unpaired electrons of the metal ions, which may occur either di-rectly or through the OCO bridges.

Typically, complex carboxylates of divalent transition metals, such as Mn,Fe, Co, Ni, have the composition ML2(RCOO)2 (L�H2O, ROH, Py, etc.) orML4(RCOO)2 and are monomeric. For (meth)acrylate complexes of these metals,this fact is confirmed by the lack of exchange interactions. According to magneticmeasurement data, these compounds are high-spin octahedral complexes, the �eff

values of which change only slightly with temperature changes (see Table 4.2).The magnetic susceptibility values of heteronuclear CuLa, NiLa [9], and CuTb[11] methacrylate complexes correspond to the presence of two uncoupled spins ofcopper ions. Over the whole temperature range studied, the magnetic susceptibility

Table 4.2 Magnetic properties of metal (meth)acrylates

�eff (�B)Antifferomagnetic

Metal carboxylates 295 K 78 K exchange Ref.

Cu2.CH2DCHCOO/4�2C2H5OH 1.40 0.22 Strong exchange [22]Cu2.CH2DC.CH3/COO/4�2H2O 1.35 – – [23]Cu2.CH2DC.CH3/COO/4�2Py 1.39 – – [23]Cu2.CH2DC.CH3/COO/4�2(4-VPy) 1.45 – – [23]Cr2.CH2DC.CH3/COO/4�4H2O 1.45 1.22 Exchange [24]ŒCuLa.CH2DC.CH3/COO/5.phen/.C2H5OH/�2 1.95 1.91 No exchange [9]Co.CH2DCHCOO/2�H2O 5.10 4.53 No exchange [22]Ni.CH2DCHCOO/2�H2O 3.60 3.47 No exchange [22]Fe.CH2DCHCOO/2�2H2O 4.92 4.35 No exchange [24]

1 The predominantly covalent nature of the Ti�O bond was found for the cyclopentadienyl Ti(III)maleate and fumarate derivatives [21]. The molar conductivities of the maleate and the fumarateare 18.3 and 6.0 cm2 mol�1, respectively. For comparison, the value for the Cp2TiCl equals86.4 cm2 mol�1.


0,5

0,6

0,7

0,8

0,9

1,0

0 100 200 3000

100

200

300

χ mT

, em

u K

mol

–1

T, K

1/χ

m, m

ol e

mu–1

Fig. 4.1 The dependence of mT and 1/m on temperature for [CuLa(CH2DC.CH3/COO/5

(phen)(C2H5OH)]2

obeys the Curie–Weiss law with relatively low Weiss constants .� D �0:82 K/, i.e.,the possibility of exchange interactions between the copper atoms is low (Fig. 4.1).

It has been found that basic copper(II) methacrylates [Cu(CH2CHCOO)2

Cu (OH)2] [25] and [Cu(CH2C(CH3/COO)2Cu(OH)2] [26] are capable of ex-hibiting ferromagnetic properties. Effective magnetic moment per one Cu(II) ion is1.86 M.B. at 293 K and 2.45 M.B. at 78 K for the basic copper(II) acrylate. The au-thors attribute the magnetic properties of the complexes to their possible tetramericstructure:

R C

O

O Cu

O

C

R

OCu

O

O

CuO

R

C

O

Cu O

O

C RO

O

Other ferromagnetic binuclear �-hydroxo copper(II) complexes have beenreported [27].

4.1.3 Electron Spectroscopy

Diffusion reflection spectra have been under investigation for the transition metalacrylates [22,28] and the copper(II) methacrylate [4,6]. There are three spin allowedtheoretically possible d–d transition in these complexes [29]:


Table 4.3 The data of electronic spectra for (meth)acrylate complexes Cu(II) [4, 6]

�max .cm�1/

Complexes �1 �2 �3

CuŒCH2DC.CH3/COO�2.bimH/2 15,152 – 39,683, 45,455Cu2ŒCH2DC.CH3/COO�4.bimH/2 13,369, 9,760 26,882 39,683, 46,296Cu3.CH2DCHCOO/5.OH/.imH/3 15,152, 9,886 26,418 47,619, 37,313Cu3.CH2DC.CH3/COO/5.OH/.imH/3 14,388, 9,668 26,884 46,296, 39,370

4T1g.F /! 4T2g.F /.�1/! 4A2g .F / .�2/! 4T1g .P / .�3/

Bands �2 and �3 in the electron spectrum of Co acrylate are observed at 18,760 and20,500 cm�1, which agrees with the octahedral coordination structure confirmedalso by the effective magnetic moment value (see Table 4.2). Electron transi-tions 3A2g ! 3T2g.F / (13,500 cm�1/ and 3A2g ! 3T1g.P / (24920 cm�1/ atteststhe existence of the similar chromophor in the Ni acrylate as well. The band at15,152 cm�1 in the spectrum of monomeric Cu methacrylate corresponds to the dxz,dyz! dx2�y2 (2B1g! 2Eg/ transition in the flat square ligand field, while the bandat 13,369 cm�1 with a shoulder at 9,760 cm�1 for the binuclear Cu methacrylatewas assigned to the dxz, dyz ! dx2�y2 and dz2 ! dx2�y2 transitions in the tetrago-nal ligand field. The appearance of a shoulder in the spectra (like the one observedin the last case) is characteristic of the bridging systems with antiferromagneticinteraction. For the complexes with mixed carboxylate functions electron transitionsdxz, dyz ! dx2�y2 and dxz, dyz ! dz2 typically overlap. For example, in the spectrafor the trinuclear Cu(II) acrylate and methacrylate complexes these transitions yieldbands at 15,152, 14,338 cm�1 and shoulders at 9,886, 9,668 cm�1, respectively [6](Table 4.3).

Certainly, on the basis of the spectral data alone, it is impossible to conclude theexact bond nature and coordination mode in metal carboxylates. Although there isa clear need for the simultaneous analysis of the X-ray diffraction data, crystallo-chemical studies of the unsaturated carboxylates are rather rare.

4.1.4 Molecular Structure

The structural data available deal mainly with methacrylate complexes. Thus thecomplexes [Cu2(CH2DCHCOO)4(C2H5OH)2](C2H5OH), [Cu2(CH2DCHCOO)4

(CH3OH)2] [30], Cu[CH2DC(CH3/COO]2(C7H6N2/2, Cu2[CH2DC(CH3/COO]4

(C7H6N2/2 [4], Cu[CH2DC(CH3/COO]2(bipy)2 [31], Cu2[CH2DC(CH3/COO]4

[(NH2/2CO]2 [32], Eu(CH2DC(CH3/COO)3 [33], [La(CH2DC(CH3/COO)3

(phen)(CH2DC(CH3/COOH)]2 [8], as well as the heteronuclear compounds[CuLa(CH2DC(CH3/COO)5(phen)(C2H5OH)]2 [9], [CuNd(CH2DC(CH3/COO)5

(phen)(EtOH)]2 [17], [CuTb(CH2DC(CH3/COO)5(phen)(H2O)]2 [11], and[NdZn2(CH2DC(CH3/COO)6(phen)(EtOH)] [34] have been studied.


6

2 9

Cu0

C

87

3

613

2

a

b

101

4

11

12 5

6′

2′

2′

6′

Cu(2)

Cu(1)

OHCH CH3

a

b

Fig. 4.2 Projection of the structure of [Cu2.CH2DCHCOO/4(CH3OH)2] along c axis (a) andformation of lantern complexes combined with hydrogen bonds (dotes) (b)

A typical feature of the compounds considered, as well as their saturated analogs,is the formation of binuclear lantern type complexes LM(RCOO)4ML. For example,the structure of copper acrylate is presented in Fig. 4.2.

Copper atoms are bound into binuclear complexes by four �2-O,O0(meth) acry-late groups. Various donor molecules (ethanol, methanol, benzimidazole, bipyridine(bipy), or phenantroline (phen))2 can act as apical ligands in these compounds. Ac-cording to the structural data, copper atoms have a square pyramid coordination with

2 Some polydentate ligands, such as phen, are capable of substituting Ocarb in the equatorial planethus destroying the metal–carboxylate core and nets. For example, in the tetranuclear Cu2La2

methacrylate complex each copper atom is coordinated with three oxygen atoms of the carboxylate


a typical elongation of the apical bond by �0.2 A [4, 30]. The pyramid base is analmost regular square with O�O distances equal 2.72–2.78 A [22]. The Cu�O dis-tances are between 1.93 and 1.98 A in solvated acrylates [30] and are around 1.97 Ain methacrylate complexes [4, 32]. The length of the C�O bonds varies insignifi-cantly between 1.248 and 1.267 A in Cu2[CH2DC(CH3/COO]4[(NH2/2CO]2 [32]and between 1.244 and 1.260 A in Cu2[CH2DC(CH3/COO]4(C7H6N2/2 [4], in-dicating delocalization of density of the -electrons of the carbonyl groups and thebidentate bridging mode of the coordination. The Cu�Cu distance in (meth)acrylatecomplexes equals 2.609 A [22], 2.617 A [22], 2.662 A [4], or 2.609 A [32]. Vari-ation in the steric conditions of the packing of the complexes and the nature ofthe axial ligands may cause metal atoms to deviate out of the equatorial plane ofoxygen atoms, i.e., to increase the Cu�Cu distance. Thus, the value of such devi-ation is 0.2178 A in the Cu2[CH2DC(CH3/COO]4(C7H6N2/2 complex [4], whichcorresponds to the maximum Cu�Cu distance in the series of the (meth)acrylatecomplexes considered. While relatively short distances (2.61–2.66 A) allow the ex-istence of the direct metal–metal bond, it is not always clear whether the exchangeinteraction between metal atoms takes place directly or through bridges of atoms.Therefore, some authors’ statements [4] regarding direct strong metal–metal interac-tion in the above-mentioned benzimidazole binuclear copper methacrylate complexwithout the data on the magnetic and resonance properties seem to be not substanti-ated enough. Lengths of the double bond in the complexes discussed are within theusual limits (1.32–1.36A), i.e., they do not take part in the additional coordinationwith a metal atom.

Binuclear fragments with double carboxylate bridges can provide a basis foroligomeric or polymeric structures. Usually in such complexes, oxygen atoms ofneighboring fragments act as axial ligands, thus creating chains. The copper(I) acry-late Cu(CH2DCHCOO) supposedly has a structure of this type [24]. Carboxylategroups occupy trans positions, one relative to another, while neighboring fragmentsare bound into ribbons by additional Cu�O bonds, i.e., the acrylate groups functionas tridentate ligands.

C

Cu

Cu

O

O

C

O

O

bridging groups and two nitrogen atoms. One of the nitrogen atoms occupies an equatorial posi-tion and another one sits at the top of the pyramid, thus preventing the formation of a polymericstructure [9].


Competition between carboxylate and accompanying ligands for the for-mation of strong bonds with a metal is known to be an important factordefining the structure of a carboxylate complex. In some cases this can causea change in the structural function of the carboxylate ligand. In particular,synthesis of the copper(II) (meth)acrylate in the presence of a donor lig-and imidazole results in an increase of nucleation of the complex formedand yields the binuclear complex Cu2[CH2DC(CH3/COO]4(C3H4N2/2 [35],as well as the trinuclear carboxylates Cu3(CH2DCHCOO)5(OH)(imH)3 orCu3(CH2DC(CH3/COO)5(OH)(imH)3 [6] along with the mononuclear coppermethacrylate Cu[CH2DC(CH3/COO]2(C3H4N2/2. Molecular unit of the com-plexes includes two �2-O,O0’-(meth)acrylate ligands and �3-OH group bindingcopper atoms. Coordination of each copper atom is augmented by monodentatecarboxylate groups and the nitrogen atoms of imidazole ligands:

Cu

O

CO Cu

OC

O Cu

OH

O

CO

O

C

O

O

C

O

Consequently, the coordination mode of one of the copper atoms is a distortedtrigonal bipyramid, while the two other atoms have the square planar mode.Coordination of a copper atom with two monodentate methacrylate groups andbenzimidazole molecules results in the formation of the complex with transsquare planar configuration (Fig. 4.3a). Each molecular unit is bound with fourneighboring units by a system of hydrogen bonds (bond length 2.721 A), thuscreating a two-dimensional supramolecular structure (Fig. 4.3b). Another donorligand, tris(2-benzimidazolylmethyl)amine (ntb) forms strong bonds with ametal atom with the participation of all four N atoms. Hence, (meth)acrylategroups in the Zn(II) complexes [Zn(ntb)(CH2DCHCOO)](NO3/(H2O) and[Zn(ntb)(CH2DC(CH3/COO)](NO3/(H2O) act as monodentate ligands [36].

In some cases the above mentioned structural changes are accompanied by thereduction of the metal ion. In particular, this was observed upon the synthesis of themixed valence complex Cu2

ICu2II[CH2DC(CH3/COO]6(PPh3/4(MeOH)2 from the

corresponding binuclear Cu(II) methacrylate crystal hydrate [37].

4.2 Metal Dicarboxylates 69

C4A

02A

01AC11

C10

C9C8 C7

C6

C2

C4

02

01

Cu1 N1AN2A

C8Ac

b

a

C5

C1

C3

N1N2

a b

Fig. 4.3 Molecular structure of Cu[CH2DC.CH3/COO�2.C7H6N2/2 (a) and diagram of its crystalpacking (b)

4.2 Metal Dicarboxylates

The presence of two carboxyl groups in dicarboxylic acid molecules expands theirfunctional capabilities as ligands and, therefore, defines the structural diversity ofthe resulting metal carboxylates. Depending on the nature of the metal and the reac-tion conditions, monosubstituted acid salts, linear, or three dimensional coordinationpolymers are formed. Let us consider the most typical groups.

4.2.1 Monomeric Salts

Acidic maleates of Co, Fe [38, 39], Zn, Ni [40, 41], Mn [42], and Mg [43, 44]with the general composition M(C4H3O4/2 � 4H2O are the typical representativesof this class of compounds. In these centro-symmetrical complexes, the metal atomis linked to two monodentate maleic acid residues (bond length for the Co�O equals2.123 A, and 2.157 A for the Fe�O), the octahedral metal coordination being com-pleted by water molecules (Fig. 4.4).

The planar structure of the maleate ligand in these complexes is stabilized by theformation of an intramolecular hydrogen bond. For example, in the Fe maleate thebond length for the H.7/ � � �O.5/ equals 1.87 A, while it equals 2.439 A for the Sbtetraphenylmaleate [45]. Overall, the maleate ligand is characterized by the param-eters close to those of the free acid (Table 4.4).

Indeed, the O � � �O distances in acidic maleate molecules usually are within a2.39–2.44 A range. However, the symmetry of the hydrogen bond can vary sig-nificantly from perfectly symmetrical to strongly asymmetrical. For example, themost asymmetrical hydrogen bond was found in the molecule of sodium acidicmaleate crystal hydrate, Na(OOCCHDCHCOOH)�3H2O, by the neutron diffractionmethod [54].


Fig. 4.4 Molecular structure of Fe(II) hydrogen maleate

There are two unequivalent fumaric acid residues in the binuclear complex[55] [Cu2(OOCCHDCHCOO)(phen)4](OOCCHDCHCOO)�11H2O, one beinga bridge connecting two copper atoms and the other functioning as a counterion. The COO� groups are coordinated to the metal atoms as monoden-tate ligands .�� D 197 cm�1/. The maleate dianion also plays a dual rolein the molecule of the Cu(II) complex Cu(L)(H2O)(OOCCHDCHCOO)2�4H2O(LD 3,10-bis(2-hydroxyethyl)-1,3,5,8,10,12-hexaazacyclotetradecane) [52]. First,this is an axial ligand binding the metal atom with a monodentate carboxyl group.�� D 249 cm�1/. On the other hand, the second carboxyl group acts as a counterion. Presence of a broad net of intramolecular hydrogen bonds cause the C�Obonds in the non-coordinated carboxyl group to become almost equivalent due todelocalization of electrons (1.255(3) and 1.262(3) A). However, a similar tendencyis also observed for the coordinated C�O bonds (1.255(3) A), as well as for thenon-coordinated ones (1.273(3) A), due to the participation of the non-coordinatedO in the formation of three types of hydrogen bonds.

Acyl derivatives of metallocenes appear in diverse structural types, includingmononuclear, binuclear, and tetranuclear complexes. As it has been noted above(Sect. 3.3.1), the reaction of Cp2TiCl2 with acetylenedicarboxylic acid at roomtemperature in a two phase system yields the binuclear carboxylate [Cp2Ti(�-OCOC�COCO)]2, while in the presence of phase transfer catalyst (tetrabutylam-monium bromide) and at lower temperatures the isostructural tetranuclear com-pound [Cp2Ti(�DOCOC�COCO)]4�5CH2Cl2 is formed [56]. The Ti�O bondlengths are within 1.95–1.98A range, and the Ti�O�C angles are within 138–144ırange. Carboxyl groups of the acetylenedicarboxylate ligand are not coplanar, thecorresponding planes forming an angle between 64.6 and 77ı for the bi- andtetranuclear complexes. Formation of the macrocyclic complex, obviously, is morefavorable. The presence of solvent molecules capable to occupy central cavity of themacrocycle facilitates the realization of this packing.

The monomeric structures of dicyclopentadienyl Ti(III) maleate and fumarate[21] were confirmed by spectroscopic and magnetic measurements. According toIR spectroscopy, the �� values are relatively low (75 cm�1 for the maleate and100 cm�1 for the fumarate), which corresponds to symmetrically bound carboxylgroups with chelating coordination. Hydrogenmaleate anions act as monoden-tate ligands in another compound, Cp2Ti(OOCCHDCHCOOH)2 that is also


Tab

le4.

4So

me

crys

tall

ogra

phic

and

stru

ctur

alch

arac

teri

stic

sof

met

aldi

carb

oxyl

ates

Met

alca

rbox

ylat

eSp

ace

grou

pG

eom

etry

Dis

tanc

e(A

)M

�OC

DCC

�OR

ef.

Na 2

C4H

2O

4�H 2

OC

2=c

Squa

re-p

iram

idal

2.40

2(c

p)1.

336(

1)1.

293(

1)[4

6]1.

281(

1)1.

250(

1)1.

264(

1)L

iC4H

3O

4�2H

2O

P2

1/c

1.99

(cp)

1.34

(1)

1.23

(1)

[47]

1.28

(1)

1.24

(1)

1.30

(1)

Cu(

HC

4H

2O

4) 2

�2H2O

I2/

mD

isto

rted

octa

hedr

on1.

933(

2)1.

336(

3)1.

235(

3)[4

8]1.

959(

2)1.

286(

3)2.

682(

2)C

uH2C

4O

4�H 2

OP

21Sq

uare

-pir

amid

al1.

97(2

)1.

33(5

)1.

28(3

)[4

8]2.

00(2

)1.

25(3

)2.

00(2

)1.

28(3

)1.

97(2

)1.

23(3

)C

u 0:0

6Z

n 0:9

4H

2C

4O

4�2H

2O

Cc

Tri

gona

lbip

iram

id1.

988(

3)1.

328(

4)1.

281(

4)[4

9]2.

125(

2)1.

240(

4)2.

022(

2)1.

247(

3)2.

109(

2)1.

278(

3)1.

999(

3)C

u 2(O

OC

CH

DCH

CO

O)

P1

Pseu

dotr

igon

alpi

ram

id,

1.98

7(5)

1.48

8(9)

[50]

trig

onal

-o-p

lana

ric

2.02

7(5)

1.37

1(14

)1.

909(

5)1.

887(

5)2.

231(

5)2.

058(

6)(c

onti

nued

)


Tab

le4.

4(c

onti

nued

)

Met

alca

rbox

ylat

eSp

ace

grou

pG

eom

etry

Dis

tanc

e(A

)M

�OC

DCC

�OR

ef.

2.12

0(6)

2.30

3(5)

2.30

6(5)

1.83

3(6)

1.86

6(5)

Cu(

C4H

3O

4)�H

2O

Pm

2 1n

Tri

gona

lpir

amid

1.99

6(6)

1.40

5(10

)1.

262(

9)[5

1]1.

292(

2)(C

6H

4) 4

Sb(O

OC

CH

DP

21=c

Tri

gona

lbip

iram

id2.

509(

3)1.

305(

7)1.

219(

2)[4

5]C

HC

OO

H)

1.25

8(6)

1.29

8(6)

1.21

3(6)

(C6H

4) 4

SbO

OC

CH

DP

21=n

Tri

gona

lbip

iram

id2.

217(

3)1.

317(

6)1.

286(

5)[4

5]C

HC

OO

Sb(C

6H

4) 4

2.20

7(3)

1.22

6(5)

1.30

6(5)

1.21

1(5)

CoC

4H

2O

4�3H

2O

Cc

Mon

ocli

nic

syng

ony

2.07

1(4)

1.32

7(8)

1.25

1(6)

[38]

2.07

9(4)

1.27

0(6)

2.08

3(4)

1.24

5(6)

2.09

6(4)

1.26

0(7)

2.10

4(4)

2.14

4(4)

CoC

4H

2O

4�5H

2O

C2

Co1

(2.0

66(2

),2.

078(

2),

2.13

1(2)

)1.

321(

3)1.

245(

2)[3

8]

1.27

5(2)

1.24

5(2)

1.27

3(2)

(con

tinu

ed)


Tab

le4.

4(c

onti

nued

)

Met

alca

rbox

ylat

eSp

ace

grou

pG

eom

etry

Dis

tanc

e(A

)M

�OC

DCC

�OR

ef.

Co2

(2.0

83(3

),2.

106(

2),

2.11

9(2)

)Fe

(C4H

3O

4) 2

�4H2O

P1

2.14

9(2)

1.33

8(3)

1.25

3(2)

[38]

2.15

7(2)

1.26

0(3)

1.22

3(2)

1.29

4(3)

Cu(

L)(

H2O

)(O

OC

CH

DC

HC

OO

) 2�4H

2O

P2(

1)2.

3601

(18)

1.33

8(4)

1.25

2(3)

coor

d

1.27

3(3)

nonc

oord

[52]

LD

3,10

-bis

(2-

hydr

oxye

thyl

)-1,

3,5,

8,10

,12-

hexa

azac

yclo

tetr

adec

ane

1.26

2(3)

free

1.25

5(3)

free

ŒZn 4

.OH

/ 2(O

OC

CH

DC

HC

OO

) 3(4

;40

-bi

py) 2

]

P2=n

1.97

3(4)

mon

oden

tate

1.95

5(3)

br

2.05

4(4)

br

2.08

9(4)

ch

2.36

7(4)

ch

1.25

8(5)

ch

1.26

0(5)

ch

1.27

295)

br

1.24

7(5)

br

1.29

4(6)

mon

oden

t

[53]


monomeric [57]. Effective magnetic moments (1.61 and 1.68 �B) suggest pres-ence of one unpaired electron at the Ti(III) atom, and relatively low Weissconstants .�4 K/ indicate that exchange interactions in the system are weak.It has been shown [58] that presence of multiple bonds in the fumarate(Cp2TiOCOCHDCHOCOTiCp2/ molecule does not affect parameters of the anti-ferromagnetic exchange interaction (J D�1:6 cm�1 and gD 1:98), the parametersbeing similar to those found for the saturated analogue containing a succinatebridge. This means that these intramolecular interactions are mainly accomplishedthrough overlapping of the ¢-orbitals. Overall complexes of dicarboxylic acidswith bidentate carboxylate bridges are efficient concentrated magnetic systems.For example, high spin octahedral Fe(III) complexes [59] [fFe(salen)g2L] or[fFe(saloph)g2L] (salenH2 D N; N 0-bis(salicylidene)ethylenediamine, salophH2 Dbis(salicylidene)-o-phenylenediamine, L D fumarate, acetylenedicarboxylate) pos-sess high exchange interaction constants (J D �4:75 to �5:47 cm�1/.

O

N

Fe

O

N O

O

C C C C

O

O N

O

Fe

N

O

Also magnetic properties data for the complex [Mn2(salen)2(�-fumarate)]�4H2Oprovide an evidence to super exchange interaction between paramagnetic centersand to high spin electron configuration [60].

4.2.2 Coordination Polymers

As mentioned above, the polydentate nature of dicarboxylic acids along with thetendency for coordination saturation of the central metal ion are important factorsconducive to predominant formation of polymeric structures. Additional stabi-lization of such systems is provided by a network of intra- and intermolecularhydrogen bonds.

There is an interesting structural peculiarity of copper(II) dihydrogenmaleatetetrahydrate [48] Cu(C4H3O4/2�4H2O. Each of the Cu atoms (coordination num-ber, CN D 4) is coordinated directly with four water molecules (bond angle� 90ı)rather than the carboxylate anions. Interaction of the cation [Cu(H2O)4]2C with fouranions [C4H3O4]� takes place via water molecules by bridging hydrogen bonds,which results in a formation of the cation chain [Cu(H2O)4]n

2nC. When maleicacid acts as monoprotic, a salt of different composition and structure may be formed.


A molecule of Zn(II) hydrogenmaleate, Zn(C4H3O4/OH�H2O, serves as an exam-ple of the polymeric chain comprised of metal ions connected by single carboxylatebridges [61]. Each zinc ion has two valence bonds – with hydrogenmaleate and withhydroxyl group, and its coordination sphere is completed to six by [C4H3O4]� andOH� anions from the neighboring zinc ions as well as two water molecules:

C

CO OH

CC

O O Zn

HO OH

O

O

HH

HH

Zn

Connection of a pair of zinc ions by the hydrogenmaleate ligand results in the for-mation of a spiral-shaped macromolecule typical for the cis-configuration of theacid. Due to intermolecular bonding via hydroxyl groups connecting zinc atoms ofneighboring strands, a secondary structure is formed similarly to a cable twistedfrom several strings (Fig. 4.5). Dehydration of the compound leads to formation of

Fig. 4.5 Morphology of the Zn(C4H3O4/OH�H2O coordination polymer


the anisotropic product [ZnH(OOCCHDCHCOO)(OH)]n with fiber type structurewhich turns into powder upon heating.

The distinctive structure of maleic acid, namely its planar configuration withcis-position of the carboxyl group about the double bond, determines its ability toform metal chelates. Both of the carboxylic groups of maleic acid can participatein valent bonding of a metal, and thus its denticity will be 4 (or higher). In mostcases, this leads to formation of seven-membered chelate cycles [38, 48, 62–65].Thus, in the Cu(II) maleate monohydrate, CuC4H2O4�H2O [48], two oxygen atomsfrom different carboxyl groups of the maleate ligand are coordinated with the Cu ionresulting in the seven-membered chelate cycle creation (average Cu�O bond lengthis 1.99 A). Square pyramidal metal coordination is completed by oxygen atoms ofthe neighboring maleate ligands and H2O molecule (Cu�O 2.26 A). Each of themaleate groups, acting as a tetradentate ligand, is bound with three Cu atoms of thepolymer framework:

Cu

H

HO

OC

O

C

O

OCu

O

O

O

O

CH

H

C

CC

Cu

Separate maleate moieties are connected via hydrogen bonds formed by watermolecules and oxygen atoms of carboxylic groups. The formation of such a two-dimensional structure is also typical for a bimetallic Cu�Zn maleate [49].

The analogous chelation pattern is observed in the case of Co(II) maleate trihy-drate [38, 66], which coordination polyhedron is a distorted octahedron. The acidanion bound with the metal ion via two oxygen atoms of the carboxyl groups [thebond lengths are O(2)�Co 2.096 A and O(4)�Co 2.071A (see Table 4.4)], pro-duces a seven-membered chelate cycle (Fig. 4.6), [38] while coordination of theO(3) and O(5) with Co atoms leads to formation of a three-dimensional framework(Fig. 4.7).

Fig. 4.6 The fragmentof the coordinationpolyhedron of Co (II) maleate

H

H

H. ...

. . ...

. . ...

. . ...

.C

O

O

O

C

C

C

C

OO O

H H

O OO

Co

OC

H


Fig. 4.7 Structure of three-dimensional coordination polymer of Co(II) maleate

In this case, maleic acid acts as a tetradentate ligand. The polyhedron is com-pleted to octahedron by two H2O molecules (O(6) and O(7)) that are cis-orientedtoward each other. The third H2O molecule is water of crystallization. Its O(12)atom has three short intermolecular contacts: with carboxyl O(3) atom not includedin the chelate cycle (2.76 A) and two atoms O(7) (2.77 A and 2.86 A) of the H2Omolecules coordinated with the neighboring Co atoms.

A different chelation type is found for the Sn(II) maleinate monohydrate,SnC4H2O4�H2O [67]. Sn atom coordinates one carboxylic group via oxygen atoms.A seven-membered chelate cycle closure is possible with the formation of an ad-ditional donor-acceptor bond with O atoms of another functional group due to thelone electron pair on the oxygen atom (Sn�O 2.817 A). Coordination is completedto CN D 6 by two O atoms from the neighboring maleic acid anion and a watermolecule:

OC

O

Sn

O

O

O

O

CH

H

C

CC

Sn

O H

H

Availability of the trigonal oxygen atoms increases the denticity of the maleateanion to five.

The effect of the synthesis conditions on the metal complex structure may beexemplified by cadmium(II) maleinate dihydrate. When obtained by different meth-ods [68, 69], the salt has the same composition, CdC4H2O4�2H2O, but different


Fig. 4.8 The crystal structureof Cd(II) maleate dihydrate

structures. In one of them, two crystallographically dissimilar cadmium atoms,Cd(1) and Cd(2) (Fig. 4.8) and two types of maleate ligands (types A and B) areobserved [68].

Thus, Cd(1) has the CND 6 and it coordinates two oxygen atoms, O(1) and O(3),of different maleate ligands along with four water molecules (coordination polyhe-dron is a distorted octahedron). For Cd(2), the CN is 8, and it chelates with four car-boxyl groups from two types of maleate anions. The type A maleate ligand, O(1–4),includes two trigonal oxygen atoms, O(1) and O(3) (one per carboxyl group),connected with Cd(1). In this way, formation of a three-dimensional coordinationpolymer is achieved which is stabilized due to hydrogen bonds between watermolecules and oxygen atoms of the carboxyl groups.

Same-formula Cd(II) maleate dihydrate [69] contains only one type of Cd ions,that has a distorted octahedral coordination. The Cd ion (CN D 4) coordinates twowater molecules and four oxygen atoms of three maleate groups. Each maleic acidanion, being a tetradentate ligand, interacts with three Cd ions to give the coordina-tion polymer.

As might be expected, formation of chelate structures for the trans-isomer, thefumaric acid, is hindered significantly by spatial remoteness of the functional groupsfrom each other. Thus, in the Co(II) fumarate pentahydrate, [CoC4H2O4�4H2O]n�nH2O, two oxygen atoms from two different carboxyl groups connect neighbor-ing cobalt atoms acting as a bridge [38, 70]. The bond length of O(3)�Co(1) andO(4)�Co(2) are 2.078 and 2.106 A, respectively. Four H2O molecules add up metalcoordination to octahedron, and the fifth one is water of crystallization. Two crystal-lographically independent Co atoms are located in the restricted positions on the C2

axis, which leads to the formation of an infinite chain of coordination polymer withcis-positioned anions of fumaric acid the fragment of which is shown in Fig. 4.9.The water of crystallization molecule is also located in two restricted positions on


Fig. 4.9 The fragment of coordination polymer structure of Co(II) fumarate pentahydrate

the C2 axes and forms strong (2.69–2.73 A) hydrogen bonds with polymeric chainsarranging them into a three-dimensional framework.

Therefore, it may be assumed that ligand conformation, such as cis- and trans-isomerism of maleic and fumaric acids may serve as the efficient means forregulation of structure and topology of coordination polymers of the kind underconsideration. The miscellaneous ligand complexes of Mn(II) maleate/fumarate and4,4-bipyridine (bipy), fMn(maleate)(�-4,40-bipy)] � 0.5H2O)g1 and fMn(fumarate)(�-4,40-bipy)(H2O)] � 0.5(�-4,40-bipy)g1 represent another example of such astructural transformation from a two-dimensional to a three-dimensional coor-dination polymer [71]. In the case of maleate complex, the Mn atoms are chelatedby the ligand carboxyl groups forming zigzag-shaped [Mn(maleate)]1 chain:

Here, one can identify two modes of carboxyl group coordination. By one of them,a carboxyl group provides a single atom bridge between two Mn atoms forming a


four-membered cycle. It is worth noting at this point that such kind of bridges areimportant for super-exchange interactions, as will be discussed below. By the secondmode, the maleate ligand, as a bidentate one, binds with two Mn centers. This resultsin the formation of a chain of consecutive seven-, eight-, seven-, and four-memberedrings. The �-4,40-bipy units interlink these chains into a two-dimensional coordina-tion polymer. The key factor in the structure of the isomeric fumarate complex is thefumarate bridges connecting different Mn atoms, so that a two-dimensional chain of14- and 22-membered cycles is formed. The carboxyl group coordination mode isboth monodentate and bidentate. Accordingly, the 2-D [Mn(fumarate)]1 layers and�-4,40-bipy units produce a three-dimensional open-frame type network. The anal-ogous structural motif was also observed for the interpenetrating three-dimensionalframework of coordination polymer for the Zn(II) fumarate with polynuclear corestructure [53]. Formation of the 3D coordination polymers is encouraged by thecapability of fumarate ligands for different coordination modes of the COO groupwith metal ions, even in the same compound. This is particularly characteristic forlanthanoid complexes. Thus, three types of fumarate ligands were discovered inthe isomorphous structures of [Sm2(OOCCHDCHCOO)3(H2O)4]�3H2O [72] and[Eu2(OOCCHDCHCOO)3(H2O)4]�3H2O [73] (1) with one chelate and one bridge-cyclic anti COO ends; (2) with one bridge-cyclic anti and one bridging syn-antiCOO ends; and (3) with one chelate and one bridging syn–syn COO ends.

As was mentioned above, employment of a neutral ligand as an additional chelat-ing agent affects the structural function of the carboxylate ligand and stability ofits bond with metal ion. In particular, competition of the ligands for the spacein the inner coordination sphere of the complexes is increasing, which generatesthe tendency for diminishing of the carboxylate ligand denticity. Sometimes, thisleads to relocation of the carboxylate anion to the axial positions,3 [74] as it isobserved in poly[[[pyrazino[2,3-f][1,10]-phenanthroline]zinc(II)]-�4-fumarato-�2-fumarate] [75] and di-�-fumarato-bis[o-phenanthroline)-dicobalt(II) [76]:

3 In particular, this is common for neutral ligands of unsaturated amines family, which almostalways displace a part of carboxylic group O atoms from the equatorial positions. In the moleculeof [Cu(N;N 0-dimethylethane-1,2-diamine)(�-fumarate)(�-H2 O)]n [74], each of the copper atomsis located at the C2 axis and has an octahedral configuration which includes equatorial N atomsof the diamine ligand and O atoms of the carboxylate ligand, and also two water molecules as theaxial ligands.


C

O

OHC

HC

CO

O

N

Co

N

O

OC

CHCH

CO

O

N

Co

N

O

O C

HC

HC O

O

C

C

O

O

HCHC

CO

O Co

O

O

C

HC

HC

O

O C

n

In the latter structure, three crystallographically different fumarate ions linkcobalt cations into the two-dimensional framework of an unusual geometry, whichconsists of consecutively alternating 8- and 28-membered rings.

Due to the similar structural pattern, the dianionic ligands in the 1,10-phenantroline [77] and benzimidazole [78] fumarate complexes of Ni(II) linkthe two neighboring metal atoms in a monodentate fashion into a dimeric unit or amolecular polymeric hetero-chain:

NiO

O

O

O

H2O

H2O

NH

N

N

NH

n

Fumarate bridges act as monodentate ligands in the 1D–3D polymeric Cu(II)complexes as well [74, 79, 80]. The dimeric units (Cu�Cu D 3.268 A) inf[Cu(OOCCHDCClCOO)(H2O)2�H2O]gn are connected by the bifunctionalchlorofumarate anions into one-dimensional bands that are cross linked by hy-drogen bonds, including those with participation of the third water molecule(Fig. 4.10a). Analogously, the fumarate dianions form a zigzag chain betweenCu(II)-diamine centers in the complex [Cu(N;N 0-dimethylethane-1,2-diamine)(�-fumarate)(�-H2O)]n [74] (Fig. 4.10b; while formation of 2D structures in[Cu(�-fumarate)(piperazine)(H2O)2]n [80] takes place with involvement of both


Fig. 4.10 Polymer structures of Cu(II) fumarate complexes f[Cu(OOCCHDCClCOO)(H2O)2�H2O]gn (a), [Cu(N,N0-dimethylethane-1,2-diamine)(�-fumarate)(�-H2 O)]n (b) and[Cu(�- fumarate)(piperazine)(H2 O)2]n (c)

fumarate bridges and piperazine molecules. Accordingly, the interpenetrating equiv-alent 2D layers create a three-dimensional interlocked network (Fig. 4.10c).

As the limiting case of structural function transformation of carboxyl groups, onemay consider the examples of complexes with all of the coordination sites aroundthe metal atom occupied by neutral ligands, in which the carboxylate anion playsonly the role of a counter ion [81, 82]:

N

NN

MN

OH2

OH2

2+

O

O

O

O

4H2O

M = Zn, Cd


The characteristic peculiarity of coordination polymers of itaconates[Cd(C5H4O4/ (H2O)2] [83] and [Ba(C5H5O4/2(H2O)] [84] is the presence intheir structure of contacts (<4.2 A) between the double bonds of the neighbor-ing molecules, which determines the possibility for a topochemical reaction ofpolymerization upon heating or irradiation.

4.2.3 Ferromagnetic Properties of Metal Dicarboxylates

Ferromagnetic behavior is an important property of the complexes under discussionand is primarily determined by their layered two-dimensional or three-dimensionalstructure. The peculiarities of the crystal structure for the Cu(II) maleate monohy-drate [63] (Fig. 4.11), in which the copper ion has a square-pyramidal coordination,and each maleate group links three copper atoms thus producing polymeric layersinterconnected by hydrogen bonds, leading to the formation in the system of distantorder interactions.

Increase in the magnitude of magnetic moment at low temperatures and posi-tive value of Weiss constant indicate a ferromagnetic character of these interactions(Table 4.5). It has been demonstrated that structural distinction of Cu(II) hy-drogenmaleate tetrahydrate [85] is reflected in the lower magnitude of J factor.C0:6 cm�1/. That is, the super exchange interactions, which take place throughwater molecules, are not as efficient in these processes as maleate bridges.

Fig. 4.11 The crystalstructure of Cu(II) maleatemonohydrate

H

Table 4.5 Ferromagnetic properties of metal dicarboxylates [55, 63]

Compounds J (cm�1) G ‚ (K) �eff (BM)

Cu(C4H2O4/�H2O (maleate) C4:3 2:0 C8 4.4 (5.9 K)1.9 (66 K)

Cu(C4H2O4/�2H2O (fumarate) C1:15 2:09 C3:2 –ŒCu2.C4H2O4/.phen/4� �34 (2 J, <130 K) 2:20 – 1.73 (75.4 K)(C4H2O4/�11H2O C17 (2 J, >130 K) 2:03 – 1.80 (145.4 K)


Fig. 4.12 The fragmentof the crystal structureof [Cu(�-C4H2O4(NH3/2]n

(H2O)m

Weak anti-ferromagnetic and ferromagnetic interactions were also found in thementioned above complex of Cu(II) fumarate with phenanthroline [55] as well as inthe [fDy2(MeCHDCHCOO)6(H2O)g0.5MeCHDCHCOOH�H2O]n [86]. As it waspointed out earlier, a typical model for Cu(II) systems with the local spin quantumnumber S D 1=2 consists of dominant ferromagnetic interaction, with alternating fer-romagnetic and anti-ferromagnetic chains in which ferromagnetic interaction takesplace via alkoxy bridges of the compound dimeric units. In the polymeric fumarateCu(�-C4H2O4(NH3/2]n(H2O)m, [87] one of the carboxylate groups in the anionacts as a single atom bridge linking two Cu(II) ions, and the other one functionsas a monodentate ligand, forming a one-dimensional chain with alternating 4- and14-membered rings (Fig. 4.12).

In the dimeric unit of the molecule, one of the bridging O atoms occupies the ax-ial position at one of the Cu atoms and at the same time, this O atom is situated in theequatorial position near the other Cu atom. Another oxygen atom is bound with theCu(II) in the opposite way. Theoretical calculations [88] showed that intramolecularferromagnetic interactions dominate in such a system and take place via bridgingalkoxide type groups. The magnitude of the spin magnetic moment, in which theprincipal contribution belongs to 3d orbitals of Cu, is 1�B per molecule. The cal-culated value for the exchange energy, �E D �0:015.7/ Ry, is in agreement withthe experimental data for the exchange interaction factors, JF D C12 cm�1 andJAF D �3:8 cm�1.

4.3 -Complexes of Metal Carboxylates 85

4.3 -Complexes of Metal Carboxylates

Coordination compounds containing -bound mono- and dicarboxylic acids( -complexes of the type VI) are obtained easier with the metals, such as Cu(I),Ag(I), Rh(I), Pd(II), and Pt(II), capable of -complex formation with monodentate -olefinic ligands, for example, with common alkenes. It is assumed [89] thatoverlapping of bonding -orbitals of CDC bond and vacant orbitals of metal atomis larger than overlapping of the orbitals participating in the reverse process due toa stronger donor abilities of the multiple bond. In the majority of complexes with’, “-unsaturated acids behave in such a fashion. In addition, the cases of bridgeformation between two different metal atoms as well as chelate formation withcoordination of both of the groups on the same atom are known (VIa–VId):

(VIa) (VIb) (VIc) (VId)

CH2 CH

O

M C OH

CH2 CH

O

M

M

C OH

CH2 CH

C OH

O M

CH2

M

CH

C

O

O

Formation of -complexes of VIa type, such as organometallic carboxylic acid(CO)10Co4HCCCOOH, apparently is promoted by coplanarity of �COOH andHC�C groups of propiolic acid [90]. In accordance with calculations by Fenske–Hall method of self-agreeing field, the carboxyl group contribution into the highestoccupied molecular orbital (HOMO) is quite large, and accounts for 15%.

In the case of olefinic system conjugated with two electron-withdrawing car-bonyl groups, the acceptor character of double bond CDC is especially high.Among the derivatives of ’; “-unsaturated dicarboxylic acids, maleic anhydridepossesses the highest acceptor capability. The most explored compounds of tran-sition metals with unsaturated mono- and dicarboxylic acids include adducts withcopper salts. Thus, CuCl produces colorless crystals of 1:1 composition with mono-carboxylic acids: crotonic, tiglinic, and ’,“-dimethacrylic acid, and also yellowproducts with dicarboxylic acids: maleic, fumaric, mesaconic, and citraconic acid.In the very initial studies [91], it was suggested that the yellow products compriseof chelates in which, besides the olefinic -bond, an interaction between Cu(I)and one of the carboxylate groups is present. Dissolution of CuCl in aqueousmaleic acid (H2L) is accompanied by formation of four thermodynamically stablecomplexes: [(H2L)CuCl] with the equilibrium constant (K/ of 9:7 � 104 at 20 ıCand solution ionic strength ranging from 1 to 0.1, [(H2L)Cu]C .KD 1:2 � 10�2/,[(HL)CuCl]� .KD 7:6 � 105/, and [(HL)Cu] .KD 2:7 � 10�2 � 3:9 � 10�1/. In-terestingly, due to copper ion coordination, the dissociation constant for maleic acid.H2L$ HC C HL�I Ka1D 2:2 � 10�2/ increases nearly tenfold, and acidic anionof maleic acid, HL�, forms a more stable complex with CuC than that of maleicacid (KD 2:02 � 104 and 1:13 � 103, respectively). In general, the behavior ofCu(I) -complexes is particular. For example, both electron-donating and electron-withdrawing substituents on the ethylene ligand favor the decrease of stability of the


Table 4.6 Stability constants of Cu(I) complexes with -ligands

K(M�1)

Ligand H2L HL L Ref.

C C

COOHHOOC

H H

1,130 20;200 [91, 93]2,300 12;000 28;000 [92]11,000(Kap) [94]

C C

COOH

HOOC

H

H

9,200 [91]7,300 11;000 15;000 [92]7,100(Kap) [94]

C CCOOHH

HH3C 1,600 [94]

corresponding Cu(I) complexes [92]. Apparently, steric factors play an importantrole in this case. Another peculiarity, as mentioned above, consists of a strongercomplex formation by deprotonated species of an unsaturated acid (Table 4.6).Negative charge on the oxygen induces electrostatic interaction between the metalion and oxygen thus increasing the complex stability constant.

In contrast to ’; “-unsaturated crotonic acid, CH3CHDCHCOOH, “;”-unsaturated vinylacetic acid, CH2DCHCH2COOH, by its complexation propensityis closer to the group of allyl alcohols. Complex formation of Cu(I) with the doublebond CDC of “;”-unsaturated carboxylate anions of vinylacetic and 2-butene-1,4-dicarbocylic acids has been proven [95]. Possibly, Cu(II) may also interact to someextent with olefinic system of these acid anions. However, the carboxylate group ofsuch anions possesses strong ligating ability towards Cu(II) cation, which makes theprobability of -complex formation of Cu(II) with these ligands to be rather low.

Formation of -complexes of silver ion with vinylacetic and fumaric acids hasnot been observed as well. Yellow complexes of platinum chloride with vinyl- andallylacetic acids have not been isolated; however, such a complex was obtained forallylmalonic acid, CH2DCHCH2CH(COOH)2 (see [96] for refs.).

The presence of efficient -dative interaction in the molecules of unsaturatedcarboxylates affects significantly the geometry of carboxylic groups, as it was ob-served for copper hydrogenmaleate, CuOOCCHDCHCOOH�H2O [51], in whichthe metal atom forms -Cu-(CDC) bond (distance CDC 1.405(10) A). Trigonalplanar coordination of Cu(I) is completed to the pyramidal one by O atom fromwater of crystallization. The C�O distances in the carboxylic groups of hydro-genmaleate anion are nearly equal [1.262(9) and 1.268(11) A]. In the analogouscomplex of maleic acid with Ag(I), the double bond of hydrogenmaleate anionis not involved in the metal ion coordination. Due to this, both the CDC bondlength (1.336(8) A) and the carboxylic groups geometry are close to those in thefree maleic acid. At the same time, one of the silver ions in the polymeric complex[Ag2(cis-C4H2O4/]n [97] is coordinated by ethylene bond of the maleate anion(Ag�C 2.448(5) A and 2.529(4) A), which results in tetrahedral configuration of

4.3 -Complexes of Metal Carboxylates 87

O6bC5

O5Cu1

Cu1 Cu1

Cu1Cu1

Cu1

Cu1 Cu1

O6

O6

O6

O6

O6

O6

O6

C5C5

C5

C5

C5

C5

C6 C6

C6

C6

C6

C6

C6

C6O5

O5

a

b

O5

O5

O5

O5

O5O5

Fig. 4.13 The layer crystal packing (a) and two crystallographically independent layers in thestructure of Cu(I) fumarate (b)

this Ag(I), in contrast to pseudo-trigonal bipyramid geometry of the other Ag(I)ion, in which -bond is not present. Is should be noted that -complexes of thetype considered herein are quite stable [98, 99] unlike organometallic compoundswhere an olefinic ligand is bound with metal by �2-bond only [100–102]. Evidently,this may be explained in terms of strong penetration of metal-O bound carboxylateanion into the molecular framework, which prevents molecules of O2 and H2Ofrom incorporation into the metal–olefin bond, as it takes place in the case of Cu(I)fumarate [50]. The complex has a tight layered structure, with parallel layers of Cu-fumarate chain linked in two directions forming a triple tier (Fig. 4.13a). Each ofthem contains an eight-membered cycle that includes O�Cu�O bridges where Cuatoms are also bound with ethylene substituents of the adjacent chains located abovethe place of the cycles, thus forming trigonal planar centers. In this structure, there


are four crystallographic elements with Cu(1), Cu(2), Cu(3a), and Cu(3b) and twocrystallographically independent fumarate ligands with CDC bond elongated dueto metal atom -coordination (see Table 4.4). The coordination sphere of Cu(1)is a pseudo-trigonal pyramid. The Cu(1) is bound with oxygen atoms O(5) andO(6) as well as olefinic CDC group, with nearly equivalent distances to C(2) andC(3) (2.039(8) and 2.057(7) A, respectively (Fig. 4.13b). Because of its length of2.335(5) A, Cu(1)-O(60/ may be considered as a bond which completes the coordi-nation geometry to pyramid. The double bond between C(2) and C(3) (1.488(9) A)is longer than the free ethylene bond (1.34 A). The Cu(2) atom has a trigonal pla-nar configuration and it is not coordinated with the olefinic group. The model givestwo locations for Cu(3), Cu(3a), and Cu(3b), coordination of which is analogous toCu(1) and Cu(2), respectively.

For maleic acid, cis-coordination of carboxylic groups about the -bond is geo-metrically possible, however, it may have sterical hindrance. This may produce anasymmetric coordination of the CDC group. In particular, the interaction of Pd(II)with maleic acid leads to formation of 4.5-membered olefin-carboxylate chelatecomplex [103]:

H

H

O

C

O

H2O OH2

HOOC

Pd2+

There are two nonequivalent proton signals observed at 4.2 and 3.3 ppm in the1H NMR spectrum of this compound corresponding to the coordinated maleic acid.While in the 2D (13C vs. 1H) spectrum, the alkene carbons resonate in the higherfield (�ı � 58 and 107 ppm, respectively) than those in the free acid (131 ppm).The observed upfield shift .�ı � 80 ppm/ is typical for metal-alkene complexes[104]. It is worth a note that the Pd(II) carboxylate formed here is a more stablecomplex than other carboxylate complexes of Pd(II).4

4.4 Unsaturated �-Oxo Multinuclear Metal Carboxylates

Trinuclear oxo-centered carboxylates of unsaturated acids and transition metal ionsof common formula [M3O(O2CR)L3]nC (RD H, CH3, C6H5, etc.; L D H2O, pyri-dine, etc.) are widely used as catalysts or intermediates in the reactions of oxidationfor many organic substrates [105, 106] as well as models of metal protein active

4 The equilibrium constants, K1 D [Pd(H2O)3OOCRC][HC]/[Pd.H2O/42C][RCOOH], for the re-

action of Pd.H2O/42C] with a series of aliphatic acids range from 0.45 to 6.4 [103].

4.4 Unsaturated �-Oxo Multinuclear Metal Carboxylates 89

centers [107, 108]. Their structure and spectral, magnetic, and redox-propertieshave been explored intensively [109–113]. In these compounds containing metal-oxocarboxylate units, oxygen atom is situated in the same plane as the surroundingthree metal atoms that comprise basically an equilateral triangle, while carboxylategroups form bridges between metal atoms.

L

L

L

OO

OO

O O

O

M

M

M OO

O

O

OO

R

R

RR

R

R

cc

cc

cc

The initial information about multinuclear complexes of transition metals with un-saturated carboxylate ligands emerged quite recently [114–118], although thesecompounds are of special interest for obtaining of metal-containing polymers withunique structure and properties.

4.4.1 IR-Spectroscopy

The frequencies of asymmetric, �as(COO�/, and symmetric, �s(COO�/, valencevibrations of carboxylate ligands point to the bridging nature of coordination in theoxo-complexes under consideration (Table 4.7).

At the same time, the spectra of Fe(III) [114] or Cr(III) [115] acrylates showvery intense bands at 1,515–1,520 and 1,435–1,440cm�1 which may be attributedto the valence asymmetric and symmetric vibrations of carboxyl group with a biden-tate cyclic coordination mode. The authors [118] associate the appearance in thespectra for some of Co oxo-carboxylates of an additional band in the region of low-frequency asymmetric vibrations (Table 4.7) with a possibly tridentate character ofone of the carboxyl oxygen atoms. Earlier, Cannon and co-workers [119] demon-strated that the planar Fe3O moiety might exhibit four basic kinds of vibrations, ofwhich the highest-energy one is twice degenerated. For the acetate complexes, it wasattributed the bands at about 600 cm�1. For mixed carboxylates, with the symmetrylowering from D3h to C2v, degeneration of the asymmetric frequency for Fe3O isremoved, and two bands emerge in the spectrum (Table 4.7).

The structural motif of the methacrylate [Al(OH)x(OH2/y(OOC(CH3/CDCH2/z]differs from the complexes described above in terms of hexacoordinated Al(III) ions


Table 4.7 Characteristic frequencies of IR spectra of unsaturated metal �-oxocarboxylates

� (cm�1)Oxocarboxylates >CDC< (COO)as (COO)s M�O M3O Ref.

[Fe3O(CH2DCHCOO)6�3H2O]OH

1,635 1,575, 1,515 1,435, 1,370 525 [114]

ŒCr3O.CH2DCHCOO/6�3H2O�OH

1,635 1,575, 1,525 1,440, 1,370 540 [115]

ŒV3O.CH2DCHCOO/6](CH2DCHCOO)

1,635 1,590, 1,527 1,444, 1,375 [116]

ŒFe3O(CH3CHDCHCOO)6�3H2O]NO3�H2O

1,657 1,562 1,412 628 [118]

ŒCo3O(CH3CHDCHCOO)6�2H2O]

1,657 1,569, 1,537 1,409 [118]

ŒFe2CoO(CH3CHDCHCOO)6�3H2O]�2H2O

1,659 1,559 1,413 575, 700 [118]

ŒFe3O(CH2DCHCOO)6�3H2O]NO3�4H2O

1,639 1,578 1,445 616 [118]

ŒCo3O(CH2DCHCOO)6�2H2O]

1,642 1,564, 1,530 1,429 [118]

being interlinked by bidentate carboxylate bridges along with hydroxyl groups andin addition, containing methacrylate groups bound with metal atoms in a monoden-tate fashion [120]:

HH

H

HH

HO

O

O

OO

C

C

C

Al Al Al

AlAlAl

O O

O

O

O

O

O

O

O

O O O

OOH

OH

H2O

OH2

OH2

H2O


4.4.2 Mass-Spectrometry

For the confirmation of multinuclear structure of the studied compounds in the ab-sence of X-ray data, mass-spectrometry analysis coupled with solvent extraction ofions is often employed. In Fig. 4.14, the positive-ion mass spectrum for the Cr(III)acrylate in aqueous alcohol solution is shown, with expanded fragment in the insert.The principal peak in the mass spectrum .m=z D 598/ corresponds to the calcu-lated mass for the cation ŒCr3O.CH2DCHCOO/6�C. The presence of peaks withm=z D 596, 599, 600, and 601 is determined by chromium and carbon isotopes.

Increase in the electric field potential enables ion fragmentation by dissocia-tion upon collision. In particular, it was reported [114] that in the mass-spectrumof Fe(III) acrylate, ions with m=z D 539, 468, and 397 are attributed to the lossof one, two, and three acrylate anions, respectively, and the ion with m=z D 341

corresponds to the loss of Fe(CH2CHCOO)3 molecule from the molecular ionŒFe3O.CH2DCHCOO/6�C. The EXAFS spectral data indicate the cluster structureas well. For example, for the Fe(III) maleate [121], the bond length Fe�Fe is 3.29 A,while the distances to the bridging oxygen atom

�R0

1

�and oxygen atoms of the

ligand setting (R1/ are 1.94 A and 2.03 A, respectively. This is in agreement withthe X-ray analysis data, for example, for ŒFe3O.�2-bethain/6.H2O/3�.ClO4/ �7H2O(R0

1 D 1:917(2) and 1.917(3) A, R1 D 2:009 and 2.034 A) [122].It should be noted that the tendency for formation of coordination polymers

due to the wide ligating capabilities of unsaturated dicarboxylic acids apparentlyexists in the case of Cr(III) and Fe(III) unsaturated oxodicarboxylates as well.This is supported by the fact of cluster cations being observed only at a rela-tively high electric field potential [123]. In addition, in the mass-spectrum of theCr(III) itaconate (Table 4.8), along with the peak corresponding to unicharged[Cr3(O(OCOC(COOH)DCH2/6]C ion, peaks for double- and even triple-charged

Inte

nsity

m / z

m / z

598

598

596

599

600

601558

Fig. 4.14 Mass-spectra of the positive ions extracted from an aqueous alcoholic solution ofcluster-type Cr(III) acrylate recorded at U D 200 V


Table 4.8 The data of mass-spectrometry analysis for Cr(III) maleate and itaconate atU D 110 V[124]

Cation m=z, Found/calculated Intensity (%)

ŒCr3O(OCOCHDCHCOOH)6]C�2CH3OH

925.91/926 6:24

ŒCr3O(OCOCHDCHCOOH)6]C�CH3OH

893.93/894 8:78

ŒCr3O(OCOCHDCHCOOH)6]C

861.89/862 31:03

ŒCr3O(OCOCHDCHCOOH)4�(OCOCHDCHCOO)]C

745.93/746 3:31

ŒCr3O(OCOCHDCHCOOH)2�(OCOCHDCHCOO)2]C

629.82/630 0:50

ŒCr3O(OCOCH2C(COOH)DCH2/6]C�2CH3OH

1009.97/1010 4:87

ŒCr3O(OCOCH2C(COOH)DCH2/6]C�CH3OH

977.95/978 5:65

Œ(Cr3O)2(OCOCH2C(COOH)DCH2/10�(OCOCH2C(COO)DCH2/]2C

880.90/881 2:55

Œ(Cr3O)2(OCOCH2C(COOH)DCH2/8�(OCOCH2C(COO)DCH2/2]2C

815.85/816 8:90


750.85/751 11:57


685.83/686 9:98


729.48/729 1:14


642.47/642 1:32

cluster cations are present in which Cr3O7� “cores” are interconnected by bridges oftetradentate itaconate ligands. The completion of ligand arrangement for the “cores”is achieved by means of itaconic acid anions in which only one of the carboxylgroups is involved in coordination.

4.4.3 Molecular Structure

As it was pointed out above, the structural data for the unsaturated �-oxocarboxy-lates are quite limited, and those available are mostly for multinuclear alkoxyderiva-tives of Zr and Ti. For example, the structure of Zr6.OH/4O4.CH2DC.CH3/COO/12

[125] contains an octahedral Zr6O4(OH)4 core in which the triangular faces of Zr6

octahedron are “capped” with �3-O and �3-OH groups. The rest of the coordinationsites of Zr is occupied by chelating or bridging methacrylate ligands. Therefore, thecoordination sphere of each of Zr atoms consists of two �3-O, two �3-OH, and fourO atoms of the methacrylic acid moiety. Interestingly, the structural characteristics


Ti(3A)

Ti(4A)

Zr(2A)

Zr(2)

Zr(1)

Ti(4)

Ti(3)

Fig. 4.15 The structure of a cluster core of Ti4Zr4O6(OBu)4(CH2(CH3)DCHCOO)16

of this complex determined from the Zr�K-end of the EXAFS-spectra appeared tobe in agreement with the X-ray data (Zr�O D 2:09 A (CN D 2) and 2.24 A (CN D6); Zr�ZrD 3.52 A (CND 2) [126]. In contrast to the Zr6 cluster under discussion,the structure of which fits well a spherical model, metal atoms in heteronuclearoxocarboxylates [127] produce extended zigzag-shaped chains of dodecahedral[ZrO8] and octahedral (TiO6] units (Fig. 4.15).The Zr atom arrangement in thiscluster, on average, includes 7.5 O atoms positioned at distance of 2.17 A, 0.5 Tiatoms (3.07 A), and 1.5 Zr (3.45 A). A single Ti atom arrangement comprises of asystem of O atoms located at distances of 1.83 A (2 atoms) and 2.04 A (4 atoms),0.5 Zr atoms, and one Ti atom.

The structure was determined for various size titanium oxo-clusters, Ti6O4(OEt)8

(OR)8 [128, 129], Ti4O2(OPrn/8(OR)8 [129], Ti4O2(OPri/6(OR)6 [128, 129],and Ti9O8(OPrn/4(OR)16 [130] (OR signifies methacrylate or acrylate groups).[Ti9O8((OPrn/4(OOCC(CH3/DCH2/16 [131] is a cluster containing the largestnumber of carboxylate ligands per Ti atom (1.78). Due to this, the molecule pos-sesses quite an open structure represented by a cycle comprised of six octahedronsattached via the points and two octahedrons joined by the edges. Hence, only twoof the oxo-bridges are �3-oxo, while six others are �2-oxo. Distribution of bridgingmethacrylate and OR groups yields a non-symmetric macrocycle.

The tendency of dicarboxylic acid carboxylates for the formation of coordina-tion polymers is also valid for their oxo-complexes. Another illustration of thisis the crystal structure of Zn(II) fumarate bipyridine complex [53]. According toX-ray analysis, the three-dimensional framework comprises of the tetranuclear hy-droxo units, [Zn4(OH)2], that produce two-dimensional polymeric layers by meansof bis-bidentate and chelate monodentate fumarate bridges (Fig. 4.16). A three-dimensional structure of the coordination polymer is formed by bridges of stacked4,40-bipy ligands between the [Zn4(OH)2(fumarate)3]1 layers. Also, 12-nuclearMn(II) oxo-complexes with acrylate [132,133] and methacrylate [134] ligands havebeen synthesized and characterized by structural studies. These complexes possessmolecular magnetic properties.


Fig. 4.16 The view of two-dimensional framework of the [Zn4(OH)2(fumarate)3]1 coordinationpolymer

4.5 Cluster-Containing Unsaturated Carboxylates

Cluster-containing monomers are molecular compounds with a framework com-prised of metal atoms located at short (no longer than 3.5 A) distances conduciveto direct M�M interactions, surrounded by ligands capable of participation inpolymerization reactions. These compounds show promise for the development ofmaterials based on individual clusters or ensembles of several atoms with size of1.5–5.0 nm and well determined structures. One of the approaches to obtaining suchsystems consists of assembling of multinuclear complexes from the mononuclearones on a polymer [135]. This approach is often utilized for non-functionalizedpolymers. Perhaps the most convenient method could be the one based on polymer-analogous transformations of polymers with involvement of particular clusters ofmono- or heterometallic type, including polymerization and co polymerization ofcluster-containing monomers. The research in this area is presently emerging. Theattempts of employment in such syntheses of the carbonyl compounds Co2(CO)8

and Fe2(CO)9 and obtaining of cluster-containing monomers derived from methylether of p-vinylbenzoic acid have been reported [136]. Carboxylate clusters of theconsidered type were obtained from the trinuclear clusters M3(CO)12 (MD Os andRu) or Os3(CO)12(CH3CN), Os3(CO)10(CH3CN)2, and (�-H)Os3(CO)10.�-OR)(RD H and Ph) and acrylic acid [137, 138]:

H(CO)3Os Os(CO)3

Os(CO)4

O OC

CH=CH2

4.5 Cluster-Containing Unsaturated Carboxylates 95

Convenient approaches to structure elucidation for such substances include the com-parison of IR and NMR spectra of the reagents, model compounds (cluster analogsof known structure), and the products obtained (in particular, of carbonyl type). Thisis especially applicable to trinuclear Ru and Os clusters, which are spectroscopicallyinformative due to the absence of bridging ligands and high symmetry.

In the above context, complexes of the cluster-of-clusters type seem to be quiteinteresting. In recent years, they attracted wide attention due to the high coordinationability of organometallic cluster carboxylate ligands, such as [(CO)9Co3C�COOH][90, 139–141]. Interaction of metal acetates, [M2(OOCCH3/4] where M D Zn,Co [142,143], Cr, Mo, and W [144,145] with cluster-containing acid, [(CO)9Co3C�COOH], yields highly organized structures with cluster cores of different geometryand M�M bond identity, which, in its turn, is surrounded by Co3 cluster units:

CoCo

Co

Co

Co

Co

CoCo

Co

O

O

O

O

O

O

M

OO

M

CoCo

Co

O C

OH

Co

CoCo

HO

C OCo

CoCo

Obviously, there are no principal limitations to functionalization of such clustermolecules with unsaturated ligands according to the method described for othercluster-containing monomers [146, 147].

The carboxylates discussed so far were narrowed to carbonyl-type clusters,although for the solution of many problems, cluster-containing monomers and poly-mers of other kinds, in particular, halogen-containing ones, are of interest.

In this connection, especially promising are derivatives of Mo(II) halogenides,multinuclear complexes of Mo6Cl12 type that are readily obtained due to a strongtendency of molybdenum(II) for association [148], among which the most propi-tious are compounds containing a stable [Mo6Cl8]4C group called the staphylonu-clear group (Fig. 4.17). This faction embodies the configuration including a central

Fig. 4.17 Thestaphylonuclearic structureof [Mo6Cl8]4C


octahedron comprised of six molybdenum atoms, which is surrounded by eight chlo-rine atoms located in the points of a somewhat distorted cube.

Importantly, the octahedron is incorporated in the cube in such a way that theMo(II) atoms are placed in the centers of the cube faces, thus providing the equiva-lence of six directions (normals) along which the shielding of molybdenum ions bychloride ions is minimal. The estimated diameter of such a cluster is about 1 nm (i.e.,the cube diagonal length, Cl�Cl, of 0.6 nm plus two times the radius of chloride ionof 0.18 nm). The stable staphylonuclear group is central in complexation reactions[149] and is able of adding up to six axial ligands such as negatively charged ions orpolar molecules, including those containing multiple bonds capable of polymeriza-tion, for example, acrylate anions in ŒMo6Cl8.CF3COO/6�n.CH2DCHCOO/n�2�[150, 151].

4.6 Metal Carboxylates with Unsaturated Ligandsof Acetylene Type

These compounds are of interest primarily due to their ability for solid phase poly-merization under ionizing irradiation. This is determined by the correspondingdistances between the reactive acetylene centers, including the required availabilityof infinite chain of short acetylene–acetylene contacts, as well as the crystal latticeenergy and cross-section for X-ray or ”-ray absorption. Most of the heavy metalsalts of propiolic acid meet these structural criteria [152–154]. In the moleculesof lanthanoid propynoate complexes [152] acetylene-acetylene contacts are of 3.5–3.94 A; such distances for thallium dimethylpropynoate [154] and scandium(III)propynoate [153] are 3.454 and 3.79–4.02 A, respectively. It is important to notethat in most of the cases, an infinite chain of such contacts is formed, as inthe structure of La2O(OOCC�CH)6(H2O)4�2H2O (Fig. 4.18a). However, intro-duction in the molecule of a bulkier ligand, such as 2,20-bipy, results in short-ening of the acetylene–acetylene contacts chain (for instance, in the complexLa2O(OOCC�CH)6(2,20-bipy)(H2O)2�2(2,20-bipy)�4H2O, it is limited to 5–6 con-tacts [152] (Fig. 4.18b), which affects the reactivity of these compounds in poly-merization transformations.

Another interesting feature of organometallic derivatives of propiolic acid isworth mentioning. The interaction of the latter with cobalt carbonyls yields clustercomplexes of VIa type, (CO)6(Co2HCC�COOH) and (CO)10(Co4HCC�COOH)[90], i.e., complexes of the cluster-containing carboxylic acid, analogs of[(CO)9Co3C�COOH] which is widely employed as a carboxylate ligand inorganometallic syntheses. It was demonstrated by the quantum chemistry calcu-lations that electron density is transferred from the Co(CO)3 to the HCC�COOHmoiety thus decreasing acidity of the carboxyl group.

Among the derivatives of dicarboxylic acids containing acetylene bonds, salts ofacetylenedicarboxylic acid attract the largest attention. The structure and propertiesof the acid were discussed in Chap. 2. As is common for metal dicarboxylates,

4.6 Metal Carboxylates with Unsaturated Ligands of Acetylene Type 97

C12 C13C32

C32C33

C33

C33

C33

C33

C23

C23C23

C23

C22

C13

C13

C13

C13

C22

C22C22

C12

C12

C12

C13

C33C33

C32

C32

C13

C13

C33

a b

Fig. 4.18 The view of dimer structures packing for La2O(OOCC�CH)6(H2O)4�2H2O (a) andLa2O(OOCC�CH)6(2,20-bipy)(H2O)2�2(2,20-bipy)�4H2O (b) complexes with formation of theshort acetylene-acetylene contacts

Fig. 4.19 Diamond-like crystal structures for Sr(II) (a) and Zn(II) (b) acetylene dicarboxylates

these compounds feature a wide variety of structures, including monomeric salts(see Sect. 4.2.1) and linear and three-dimensional coordination polymers. A generalstructural motif may be described as a chain structure comprised of polyhedralmetal centers (for example, tetrahedral as in [Be(C4O4/(H2O)4]n [155] and[Zn(C4O4/2(HTEA)2]n where HTEA is triethylamine [156], square pyramidalin f[Cu(C4O4/(H2O)3�H2Ogn [157] and [Cu(C4O4/(Py)2(H2O)]n [158] trigonalprism in [Cd(C4O4/(Phen)]n [159], and octahedral in [M(C4O4/(Phen)(H2O)2]n

(where MD Co(II) [160] or Mn(II) [161]), [M(C4O4/(Py)2(H2O)2]n (MD Fe, Co,and Ni) [158], and [Co(C4O4/(H2O)4�2H2O]n [162] interconnected by acetylenedi-carboxylate dianions that most often are mono-coordinated. The presence of asystem of hydrogen bonds and � interactions as, for instance, in the complexeswith phenanthroline ligands, normally results in formation of three-dimensionalcoordination polymers. Of interest are a diamond-like crystal structure for an-hydrous acetylenedicarboxylate [Sr(C4O4/] [163] (Fig. 4.19a) and that of theabove-mentioned complex Zn(C4O4/2(HTEA)2]n.[156]. In the latter, each of thezinc ions is bound in a monodentate fashion with four different carboxylate bridgesthus producing two interpenetrating diamond-like frameworks (Fig. 4.19b).

It is suggested that four carboxylate C atoms in each of the tetrahedral Zn(CO2/4

units, which occupy C points in the diamond structure, may increase and expand the


Tab

le4.

9St

ruct

ural

char

acte

rist

ics

ofm

etal

carb

oxyl

ates

wit

hac

etyl

ene

liga

nds

Coo

rdin

atio

nD

ista

nce

(A)

mod

eof

the

Met

alca

rbox

ylat

eC

OO

Geo

met

rySp

ace

grou

pC

�Oco

orC

�Oco

ncM

�OR

ef.

La 2

O(O

OC

C�C

H) 6

(H2O

) 4�2H

2O

II,I

IIP

21=c

2.59

9(2)

trid

ent

[152

]2.

523(

2)tr

iden

t

2.65

8(2)

trid

ent

2.54

7(2)

br

2.51

4(2)

br

2.58

3(2)

ch

2.55

7(2)

ch

La 2

O(O

OC

C�C

H) 6

(2,2

0

I,II

,III

P1

1.24

8(3)

1.23

7(4)

2.71

2(1)

trid

ent

[152

]-b

ipy)

(H2O

) 2�2(

2,20

-bip

y)�4H

2O

2.52

1(2)

trid

ent

2.64

8(2)

trid

ent

2.51

1(2)

br

2.48

4(2)

br

2.48

0(2)

mon

o

Œ(C

H3/ 2

Tl(

OO

CC

�CH

)]II

ISq

uare

-pyr

amid

alP

nma

2.76

(2) b

r[1

54]

2.39

(2) tr

iden

t

2.65

(2) tr

iden

t

Sc(O

OC

C�C

H) 3

III

Oct

ahed

ron

Pa3

2.09

1(2)

br[1

53]

2.08

1(2)

br

f[Cu(

C4O

4/(

H2O

) 3]�H

2O

g nI

Squa

re-p

yram

idal

P2

1=c

1.27

3(2)

1.23

1(3)

1.95

55(1

5)[1

57]

ŒFe(

C4O

4/(

Py) 2

(H2O

) 2] n

IO

ctah

edro

nC

2=c

1.27

1(1)

1.23

3(2)

2.14

58(8

)[1

58]

ŒCo(

C4O

4/(

Py) 2

(H2O

) 2] n

IO

ctah

edro

nC

2=c

1.27

0(2)

1.23

1(2)

2.11

1(1)

[158

]ŒN

i(C

4O

4/(

Py) 2

(H2O

) 2] n

IO

ctah

edro

nC

2=c

1.26

8(3)

1.22

4(4)

2.08

6(2)

[158

]ŒC

u(C

4O

4/(

Py) 2

(H2O

) 2] n

ISq

uare

-pyr

amid

alP

212

12

11.

275(

8)1.

233(

8)1.

953(

3)[1

58]

ŒCo(

C4O

4/(

H2O

) 4]�2

H2O

]I

Oct

ahed

ron

P2

1=a

1.26

6(2)

1.23

7(2)

2.10

5(1)

[162

]

4.6 Metal Carboxylates with Unsaturated Ligands of Acetylene Type 99

Table 4.10 The coordination mode of the COO in unsaturated metal carboxylates

Metal carboxylate Structure Ref.

Pd(O2CCHDCHCO2H)2(dppf) [165]

ŒEu(O2CC(Me)DCH2/3]n [33]

Cu3[CH2DC(Me)CO2]5(OH](imidazole)3

[6]

ŒCu(O2CCHDCHCO2/

(C10H8N2/]n2H2O[166]

ŒNi(H2O)6][Ni(H2O)2

(O2CCHDCHCO2/]�4H2O[64]

ŒMg(O2CCHDCHCO2/(H2O)4�H2O [167]

ŒMn(O2CCHDCHCO2/(phen)]n ,ŒMn(O2CCHDCHCO2/(phen)]n �nH2O

[168]

syn-anti syn-anti

ŒMn(O2CCHDCHCO2/(bpy)] [168]

anti-antisyn-syn


framework, in other words, to serve as a molecular building block for creation ofnew elaborated structures. Representative metal carboxylates of the discussed typeand their structural characteristics are listed in the Table 4.9.

Therefore, the presented data demonstrates that unsaturated carboxylates, similarto their saturated analogs, reveal a variety of structures, from mono- and binuclear tocluster and polymeric complexes. The binding mode of carboxyl group with metalatom is also represented by different types (purely ionic and different degree cova-lent bond). The most common coordination modes are bidentate bridging, bidentatecyclic, and chelating, a more rare one is monodentate. The cases of their combi-nation in the same molecule are quite frequent. A special manifest of unsaturatedfunction in the carboxylate ligands is -complexes represented primarily by Cu(II),Ag(I), and Pd(II) carboxylates. Basically all of the mentioned coordination modeshave been confirmed by crystallography. It is illustrated schematically by severalcharacteristic examples (Table 4.10).

Despite the quite common structure and properties with those of saturated metalcarboxylates [164], metal carboxylates of the kind under consideration reveal manyspecific features which separate them into an independent area and provide themwith new properties. It is especially relevant to their polymerization transformationsthat actually convert these materials into metal-polymeric nanocomposites.

References

1. M.A. Porai-Koshits, in Krystallokhimiya (Itogi nauki i tekhniki) Crystal Chemistry (Advancesin Science and Crystal Engineering), vol. 15, ed. by E.A. Gilinskaya (VINITI, Moscow,1981), p. 3

2. G.B. Deacon, R.J. Phillips, Coord. Chem. Rev. 33, 227 (1980)3. M.A. Porai-Koshits, Zh. Strukt. Khimii 21, 146 (1980)4. Y. Wang, Q. Shi, B. Yang, Q.Z. Shi, Y. Gao, Z. Zhou, Sci. China B 42, 363 (1999)5. M. Camail, M. Humbert, A. Margaillan, A. Riondel, J.L. Vernet, Polymer 39, 6525 (1998)6. Y.Y. Wang, L.J. Zhou, Q. Shi, Q.Z. Shi, Y.C. Gao, X. Hou, Transit. Met. Chem. 27, 145 (2002)7. Y. Zhu, W.-M. Lu, M. Ma, F. Chen, Acta Crystallogr. E 61, m2044 (2005)8. W.-M. Lu, Z.-P. Shao, J.-B. Hu, X.-Y. Luo, N. Dong, J.-M. Gu, J. Coord. Chem. 40,

145 (1996)9. B. Wu, Wei-Min Lu, Xiao-Ming Zheng X, Chin. J. Chem. 20, 846 (2002)

10. B. Wu, W. Lu, X. Zheng, J. Coord. Chem. 56, 65 (2003)11. B. Wu, W.-M. Lu, X.-M. Zheng, J. Coord. Chem. 55, 497 (2002)12. Y. Zhu, W.-M. Lu, F. Chen, Acta Crystallogr. E 60, m963 (2004)13. Y. Zhu, W. Lu, F. Chen, Acta Crystallogr. E 60, m1459 (2004)14. Y. Zhu, W. Lu, F. Chen: Acta Crystallogr. E 61, m1610 (2005)15. M.J. Vela, B.B. Snider, B.M. Foxman, Chem. Mater. 10, 3167 (1998)16. E. S. Rufino, E.E.C. Monteiro, Polymer 41, 4213 (2000)17. B. Wu, W. Lu, X. Zheng, Transit. Met. Chem. 28, 323 (2003)18. Y. Lu, W. Lu, B. Wu, L. Wang, J. Coord. Chem. 53, 15 (2001)19. B. Wu, Acta Crystallogr. E 62, m2084 (2006)20. B. Wu, Y.-S. Guo, Acta Crystallogr. E 60, m1261 (2004)21. R.S.P. Coutts, P.C. Wailes, Aust. J. Chem. 20, 1579 (1967)22. G.I. Dzhardimalieva, A.D. Pomogailo, V.I. Ponomarev, L.O. Atovmyan, Yu.M. Shulga, A.G.

Starikov, Izv. Akad. Nauk. SSSR, Ser. Khim., 1525 (1988)

References 101

23. W. Kuchen, J. Schram, Angew. Chem. Int. Ed. Engl. 27, 1695 (1988)24. G.I. Dzhardimalieva, I.N. Ivleva, Yu.M. Shulga, E.N. Frolov, A.D. Pomogailo, Izv. Akad.

Nauk. SSSR, Ser. Khim., 1145 (1998)25. P.A. Vasil’ev, Zh. Neorg. Khim. 30, 1688 (1994)26. P.A. Vasil’ev, A.L. Ivanov, O.N. Rubacheva, A.N. Glebov, Zh. Neorg. Khim. 41, 1747 (1996)27. V.V. Volkov, Yu.V. Rakitin, V.T. Kalinnikov, Koord. Khim. 9, 31(1983)28. A.P. Botsman, L.N. Fedorova, A.I. Vailchenko, G.I. Dzhardimalieva, A.D. Pomogailo, Izv.

Akad. Nauk. SSSR, Ser. Khim., 576 (1992)29. E. Liver, Electronic Spectroscopy of Inorganic Compounds (Mir, Moscow, 1987)30. V.I. Ponomarev, L.O. Atovmyan, G.I. Dzhardimalieva, A.D. Pomogailo, I.N. Ivleva, Koord.

Khim. 14, 1537 (1988)31. G. Yi-Ci, W. Yao-Yu, S. Qi-Zhen, Polyhedron 10, 1893 (1991)32. W. Yao-Yu, S. Qian, S. Qi-Zhen, et al., Chin. Sci. Bull. 43, 2512 (1998)33. N.V. Petrochenkova, B.V. Bukvetskii, A.G. Mirochnik, V.E. Karasev, Koord. Khim. 28,

67 (2002)34. B. Wu, W. Lu, X. Zheng, J. Coord. Crystallogr. 33, 203 (2003)35. Y.-Y. Wang, Q. Shi, Q.-Z. Shi, Y.-C. Gao, Z.-Y. Zhou, Polyhedron 18, 2009 (1999)36. H. Wu, Y. Gao, K. Yu, Transit. Met. Chem. 29, 175 (2004)37. Y.-Y. Wang, Q. Shi, Q.-Z. Shi, Y.-C. Gao, X. Hou, Polyhedron 19, 891 (2000)38. N.P. Porollo, Z.G. Aliev, G.I. Dzhardimalieva, I.N. Ivleva, I.E. Uflyand, A.D. Pomogailo, N.S.

Ovanesyan, Izv. Akad. Nauk. SSSR, Ser. Khim., 375 (1997)39. R.K. Barman, R. Chakrabarty, B.K. Das, Polyhedron 21, 1189 (2002)40. M.P. Gupta, H.J. Geise, A.T.H. Lenstra, Acta Crystallogr. C 40, 1152(1984)41. A. Sequeira, H. Rajagopal, Acta Crystallogr. C 48, 1192 (1992)42. T. Lis, Acta Crystallogr. C 39, 39 (1983)43. M.P. Gupta, C. Van Alsenov, T.H. Lenstra, Acta Crystallogr. C 40, 1526 (1984)44. F. Vanhouteghem, A.T.H. Lenstra, Acta Crystallogr. B 43, 523 (1987)45. V.V. Sharutin, O.K. Sharutina, A.P. Pakusina, V.K. Belsky, J. Organomet. Chem. 87,

536–537 (1997)46. M.N.G. James, G.J.B. Williams, Acta Crystallogr. B 30, 1257 (1974)47. M.P. Gupta, S.M. Prasad, T.N.P. Gupta, Acta Crystallogr. B 31, 37 (1975)48. C.K. Prout, J.R. Carruthers, F.J.C. Rossotti, J. Chem. Soc. A 3342 (1971)49. J. Cernak, J. Chomic, Ch. Kappenstein, F. Robert, J. Chem. Soc. Dalton Trans. 2981 (1997)50. D.M. Young, U. Geiser, A.J. Schultz, H. Hau Wang, J. Am. Chem. Soc. 120, 1331 (1998)51. P.Yu. Zavalii, M.G. Myus’kiv, E.I. Gladyshevskii, Crystallografiya 30, 688 (1985)52. J.C. Kim, A.J. Lough, J. Chem. Crystallogr. 35, 535 (2005)53. J. Tao, M.-L. Tong, J.-X. Shi, X.-M. Chen, S.W. Ng. Chem. Commun., 2043–2044 (2000)54. G. Olovsson, I. Olovsson, M. S. Lehmann, Acta Crystallogr. C 40, 1521 (1984)55. Y.Y. Wang, X. Wang, Q.Z. Shi, Transit. Met. Chem. 27, 481 (2002)56. T. Guthner, U. Thewalt, J. Organomet. Chem. 350, 235 (1988)57. K. Doppert, R. Sanchez-Delgado, H.-P. Klein, U. Thewalt: J. Organomet. Chem. 233,

205 (1982)58. L.C. Francesconi, D.R. Corbin, A.W. Clauss, D.N. Hendrickson, G.D. Stucky, Inorg. Chem.

20, 2078 (1981)59. P. Kopel, Z. Sindelar, R. Klicka, Transit. Met. Chem. 23, 139 (1998)60. S. Biswas, K. Mitra, B. Adhikary, Transit. Met. Chem. 30, 586 (2005)61. I. Vancso-Szmercsanyi, A. Kallo, J. Polym. Sci. A Polym. Chem. 20, 639 (1982)62. N.P. Porollo, G.I. Dzhardimalieva, I.E. Uflyand, A.D. Pomogailo, Russ. Chem. J., 60,

190 (1996)63. J. Padilla, W.E. Hatfield, J.R. Wasson, W.E. Estes, Transit. Met. Chem. 14, 217 (1989)64. Y.-Q. Zheng, Zu-P. Kong, J. Coord. Chem. 56, 967 (2003)65. D.A. Merkulov, V.I. Kornev, Zh. Neorg. Khim. 44, 439 (1999)66. M. Pajtasova, E. Jona, M. Koman, D. Ondrusova, Pol. J. Chem. 75, 1209 (2001)67. J.C. Dewan, J. Silver, R.H. Andrew et al., J. Chem. Soc. Dalton Trans. 368 (1977)68. M.I. Post, J. Trotter, J. Chem. Soc. Dalton Trans. 674 (1974)


69. A. Hempel, S.E. Hull, Acta Crystallogr. B 35, 2215 (1979)70. Y.-Q. Zheng, H.-Z. Xie, J. Solid State Chem. 177, 1351 (2004)71. Z. Shi, L. Zhang, S. Gao, G. Yang, J. Hua, L. Gao, S. Feng, Inorg. Chem. 39, 1990 (2000)72. W.-H. Zhu, Z.-M. Wang, S. Gao, Dalton Trans. 765 (2006)73. X. Li, Y.-Q. Zou, J. Chem. Cryst. 35, 351 (2005)74. P.S. Mukherjee, D. Ghoshal, E. Zangrando, T. Mallah, N.R. Chaudhuri, Eur. J. Inorg. Chem.

23, 4675 (2004)75. G.-B. Che, B. Liu, Acta Crystallogr. E 62, m2036 (2006)76. J.-F. Ma, J. Yang, J.-F. Liu, Acta Crystallogr. C 59, m304 (2003)77. J.-F. Ma, J. Yang, J.-F. Liu, Acta Crystallogr. E 59, m900 (2003)78. Y. Liu, D.-J. Xu, Acta Crystallogr. E 60, m1002 (2004)79. H. Billetter, I. Pantenburg, U. Ruschewitz, Acta Crystallogr. E 62, m881 (2006)80. P.S. Mukherjee, S. Dalai, G. Mostafa, E. Zangrando, T.-H. Lu, G. Rogez, T. Mallah,

N. R. Chaudhuri, Chem. Commun. 15, 1346 (2001)81. J. Yang, J.-F. Ma, J.-F. Liu, Acta Crystallogr. E 59, m324 (2003)82. J. Yang, J.-F. Ma, L. Li, J.-F. Liu, Acta Crystallogr. E 59, m568 (2003)83. J.E. Contreras, V. Belkis Ramirez, G. Diaz de Delgado, J. Chem. Crystallogr. 27, 391 (1997)84. A.V. Briceno, G. Diaz de Delgado, B.V. Ramirez, W.O. Velasquez, A.B. Bahsas, J. Chem.

Crystallogr. 29, 785 (1999)85. L.W. ter Haar, W.E. Hatfield, Mol. Cryst. Liq. Cryst. 107, 171 (1984)86. R. Baggio, M.T. Garland, O. Pena, M. Perec, Inorg. Chim. Acta. 358, 2332 (2005)87. P.S. Mukherjee, T.K. Maji, G. Mostafs, J. Ribas, M.S. Fallah, N.R. Chaudhuri, Inorg. Chem.

40, 928 (2001)88. K.L. Yao, L. Zhu, Z.L. Liu, Eur. Phys. J. B 39, 283 (2004)89. Fisher E., Vener G., -Metal Complexes (Mir, Moscow, 1968)90. V. Calvo-Perez, A. Vega, P. Cortes, E. Spodine, Inorg. Chim. Acta. 333, 15 (2002)91. R.M. Keefer, L.J. Andrews, R.E. Kepner, J. Am. Chem. Soc. 71, 2379 (1949)92. N. Navon, A. Masarwa, H. Cohen, D. Meyerstein, Inorg. Chim. Acta. 261, 29 (1997)93. G.V. Buxton, J.C. Green, R.M. Sellers, J. Chem. Soc. Dalton Trans. 2160 (1976)94. D. Meyerstein, Inorg. Chem. 14, 1716 (1975)95. R.K. Resnik, B.E. Douglas, Inorg. Chem. 2, 1246 (1963)96. M. Herberhold, -Metal Complexes (Mir, Moscow, 1975)97. G. Smith, D.S. Sagatys, C. Dahlgren, D.E. Lynch, R.C. Bott, Z. Krystallogr. 210, 44 (1995)98. J.W. Sprengers, M.J. Agerbeek, C.J. Elsevier, Organometallics 23, 3117 (2004)99. N. Navon, A. Masarwa, H. Cohen, D. Meyerstein, Inorg. Chim. Acta. 261, 29 (1997)

100. O. Hamed, P.M. Henry, Organometallics 16, 4903 (1997)101. K. Zaw, P.M. Henry, Organometallics 11, 2008 (1992)102. R. Kumar, F.R. Fronczek, A.W. Maverick, A.J. Kim, L.G. Butler, Chem. Mater. 6, 587 (1994)103. T. Shi, L.I. Elding, Inorg. Chem. 37, 5544 (1998)104. P.A. Chaloner, S.E. Davies, P.B. Hitchcock, J. Organomet. Chem. 527, 145 (1997)105. R.D. Cannon, R.P. White, Prog. Inorg. Chem. 36, 195 (1988)106. C.D. Chandler, C. Roger, M.J. Hampden-Smith, Chem. Rev. 93, 1205 (1993)107. S.J. Lippard, Angew. Chem. Int. Ed. Engl. 27, 344 (1988)108. D. Lee, S.J. Lippard, J. Am. Chem. Soc. 123, 4611 (2001)109. S.M. Oh, S.R. Wilson, D.N. Hendrickson, S.E. Woehler, J. Am. Chem. Soc. 109, 1073 (1987)110. R.W. Saalfrank, A. Scheure, K. Pokorny, H. Maid, U. Reimann, F. Hampel, F.W. Heinemann,

V. Schunemann, A.X. Trautwein, Eur. J. Inorg. Chem., 1383 (2005)111. K.I. Turta, S.G. Shova, F.K. Zhovmir, V.M. Mereakre, D.N. Prodius, M. Gdanets,

I.G. Kadelnik, Y.A. Simonov, Zh. Neorg. Khim. 48, 80 (2003)112. L.D. Slep, A. Mijovilovich, W. Meyer-Klaucke, T. Weyhermuller, E. Bill, E. Bothe, F. Neese,

K. Wieghardt, J. Am. Chem. Soc. 125, 1554 (2003)113. T. Fujihara, J. Aonahata, S. Kumakura, A. Nagasawa, K. Murakami, T. Ito, Inorg. Chem. 37,

3779 (1998)

References 103

114. Yu.M. Shulga, O.S. Roshchupkina, G.I. Dzhardimalieva, I.V. Chernushevich, A.F. Dodonov,Y.V. Baldokhin, P.Ya. Kolotyrkin, A.S. Rozenberg, A.D. Pomogailo, Izv. Akad. Nauk. SSSR,Ser. Khim., 1739 (1993)

115. Yu.M. Shulga, I.V. Chernushevich, G.I. Dzhardimalieva, O.S. Roshchupkina, A.F. Dodonov,A.D. Pomogailo, Izv. Akad. Nauk. SSSR, Ser. Khim., 1047 (1994)

116. G.I. Dzhardimalieva, I.N. Ivleva, Yu.M. Shulga, E.N. Frolov, A.D. Pomogailo, Izv. Akad.Nauk. SSSR, Ser. Khim., 1145 (1998)

117. P.A. Vasilev, A.L. Ivanov, A.N. Glebov, Zh. Obshch. Khim. 68, 535 (1998)118. G. Losada, M.A. Mendiola, M.T. Sevilla, Inorg. Chim. Acta. 255, 125 (1997)119. L. Montri, R.D. Cannon, Spectrochim. Acta A 41, 643 (1985)120. A.R. Vilchis-Nestor, V. Sanchez-Mendieta, F. Urena-Munez, R. Lopez-Castanares,

J.A. Ascencio, J. Appl. Polym. Sci. 102, 5212 (2006)121. A.D. Pomogailo, V.G. Vlasenko, A.T. Shuvaev, A.S. Rozenberg, G.I. Dzhardimalieva, Zh.

Kolloid. Khim. 64 530 (2002)122. M.-L. Tong, X.-M. Chen, Zi-M. Sun, D.N. Hendrickson, Transit. Met. Chem. 26, 195 (2001)123. G.I. Dzhardimalieva, A.D. Pomogailo, Macromol. Symp. 186, 147 (2002)124. G.I. Dzhardimalieva, A.D. Pomogailo, Khim. Zh. Armenii. 52, 9 (1999)125. G. Kickelbick, U. Schubert, Chem. Ber. 130, 473 (1997)126. G. Kickelbick, M.P. Feth, H. Bertagnolli, B. Morari, G. Trimmel, U. Schubert, Monatsh.

Chem. 133, 919 (2002)127. B. Moraru, G. Kickelbick, U. Schubert, Eur. J. Inorg. Chem. 5, 1295 (2001)128. U. Schubert, G. Trimmel, B. Moraru, W. Tesch, P. Fratzl, S. Gross, G. Kickelbick, N. Husing,

Mater. Res. Symp. Proc. 628, 2.3.1 (2000)129. B. Moraru, N. Husing, G. Kickelbick, U. Schubert, P. Fratzl, H. Peterlik, Chem. Mater. 14,

2732 (2002)130. I. Mijatovic, G. Kickelbick, M. Puchberger, U. Schubert, New J. Chem. 27, 3 (2003)131. G. Kickelbick, U. Schubert, Eur. J. Inorg. Chem. 159 (1998)132. F. Palacio, P. Oliete, U. Schubert, I. Mijatovic, N. Husing, H. Peterlik, J. Mater. Chem. 14,

1873(2004)133. R. Cusnir, G. Dzhardimalieva, S. Shova, D. Prodius, N. Golubeva, A. Pomogailo,

C. Turta, International Conference on Coordination Chemistry, Jerusalem, Israel, 20–25 July,(2008 , p. 475

134. S. Willemin, B. Donnadien, L. Lecren, B. Henner, R. Clerac, C. Guerin, A.V. Pokrovskii,J. Larionova, New J. Chem. 28, 919 (2004)

135. A.D. Pomogailo, A.S. Rozenberg, I.E. Uflyand: Metal nanoparticles in polymers (Khimiya,Moscow, 2000)

136. J.C. Gressier, G. Levesque, A. Patin, Polymer Bull. 8, 55 (1982)137. V.A. Maksakov, V.P. Kirin, S.N. Konchenko, N.M. Bravaya, A.D. Pomogailo, A.V. Virovets,

N.V. Podberezskaya, I.G. baranovskaya, S.V. Tkachev, Izv. Akad. Nauk. 1293 (1993)138. N.M. Bravaya, A.D. Pomogailo, Metal-Containing Polymeric Materials, ed. by C.U. Pittman

Jr., C.E. Carraher Jr., M. Zeldin, B. Culberston (Plenum Publ. Corp., New York, 1996), p.51139. J.E. Hallgren, C.S. Eschbach, D. Seyferth, J. Am. Chem. Soc. 94, 2547 (1972)140. D. Seyferth, J.E. Hallgren, C.S. Eschbach, J. Am. Chem. Soc. 96, 1730 (1974)141. W. Cen, K.J. Haller, T.P. Fehlner, Inorg. Chem. 32, 995 (1993)142. W. Cen, K.J. Haller, T.P. Fehlner, Inorg. Chem. 30, 3120 (1991)143. R.L. Sturgeon, M.M. Olmstead, N.E. Schore, Organometallics 10, 1649 (1991)144. V. Calvo-Perez, T.P. Fehlner, A.L. Rheingold, Inorg. Chem. 35, 7289 (1996)145. W. Cen, P. Lindenfeld, T.P. Fehlner, J. Am. Chem. Soc. 114, 5451 (1992)146. S.P. Tunik, S.I. Pomogailo, G.I. Dzhardimalieva, A.D. Pomogailo, I.I. Chuev, S.M. Aldoshin,

A.B. Nikolskii, Izv. Akad. Nauk. SSSR, Ser. Khim., 975 (1993)147. S.I. Pomogailo, V.A. Ershova, G.V. Shilov, G.I. Dzhardimalieva, A.D. Pomogailo, et al.,

J. Organomet. Chem. 690, 4258 (2005)148. A.A. Opalovskii, I.I. Tychinskaya, Z.M. Kuznetsova, P.P. Samoilov, Halogenides of Molibde-

num (Nauka SO AN SSSR, Novosibirsk, 1972)


149. D.H. Johnston, D.C. Gaswick, M.C. Lonergan, C.L. Stem, D.F. Shriver, Inorg.Chem. 31,1869 (1992)

150. N.D. Golubeva, O.A. Adamenko, G.N. Boiko, A.D. Pomogailo, Inorg. Mater. 40, 363 (2004)151. O.A. Adamenko, G.V. Lukova, N.D. Golubeva, V.A. Smirnov, G.N. Boiko, A.D. Pomogailo,

I.E. Uflyand, Dokl. Phys. Chem. 381, 360 (2001)152. J.S. Brodkin, B.M. Foxman, Chem. Mater. 8, 242 (1996)153. J.S. Brodkin, B.M. Foxman, J. Chem. Soc. Chem. Commun., 1073 (1991)154. M.J. Moloney, B.M. Foxman, Inorg. Chim. Acta. 229, 323 (1995)155. C. Robl, S. Hentschel. Z. Naturforsch, Teil B 45, 149 (1990)156. J. Kim, B. Chen, T.M. Reineke, H. Li, M. Eddaoudi, D.B. Moler, M. O’Keeffe, O.M. Yaghi,

J. Am. Chem. Soc. 123, 8239 (2001)157. H. Billetter, F. Hohn, I. Pantenburg, U. Ruschewitz, Acta Crystallogr. C. 59, m130 (2003)158. I. Stein, M. Speldrich, H. Schilder, H. Lueken, U. Ruschewitz, Z. Anorg. Allg. Chem. 633,

1382 (2007)159. H.-Y. Wang, S. Gao, L.-H. Huo, J.-G. Zhao, Acta Crystallogr. E 63, m2995 (2007)160. H.-Y. Wang, S. Gao, L.-H. Huo, J.-G. Zhao, Acta Crystallogr. E 62, m3152 (2006)161. H.-Y. Wang, S. Gao, L.-H. Huo, J.-G. Zhao, Acta Crystallogr. E 62, m3281 (2006)162. I. Pantenburg, U. Ruschewitz, Z. Anorg. Allg. Chem. 628, 1697 (2002)163. F. Hohn, I. Pantenburg, U. Ruschewitz, Chem. Eur. J. 8, 4536 (2002)164. V.V. Skopenko, A.Yu. Tsivadze, L.I. Saranskii, A.D. Garnovskii, Koordinatsionnaya khimiya

[Coordination Chemistry] (Akademkniga, Moscow, 2007)165. Y.C. Neo, J.S.L. Yeo, P.M. Low, S.W. Chien, T.C.W. Mak, J.J. Vittal, T.S.A. Hor,

J. Organomet. Chem. 658, 159 (2002)166. Z.-Y. Li, D.-J. Xu, W.-L. Shi, X. De-YuChen, J.-Y. Wu, M.Y. Chiang, Chin. J. Chem. 20,

390 (2002)167. J. Baier, U. Thewalt, Z. Anorg. Allg. Chem. 628, 1890 (2002)168. C. Ma, C. Chen, Q. Liu, F. Chen, D. Liao, L. Li, L. Sun, Eur. J. Inorg. Chem., 2872 (2003)

Chapter 5Polymerization and Copolymerization of Saltsof Unsaturated Carboxylic Acids

Polymerization of unsaturated metal carboxylates is a unique method of synthesisof metallopolymers with a metal atom included in each monomeric unit. In utmostcases, metallopolymers of the type under consideration are prepared by radicalpolymerization, which comprises the same elementary steps as for conventionalmonomers. The rate of radical polymerization .w/ is described by the knownequation:

w D �dŒM�=dt D k1=2i .kp=k

1=2t /ŒM�ŒI�1=2 (5.1)

where ki, kp, and kt are the rate constants for chain initiation, propagation, andtermination; [M] and [I] are the concentrations of the monomer and the initiator.

However deviations from this main equation occur quite often due to the natureof the monomers used.

An equation for the kinetic parameters and the average rate of polymerization,P , is as follows:

1

NP D.wik

1=2t /

kpŒM�C kM

kpD ks

kp

ŒS�

ŒM�(5.2)

where wi, is the initiation rate, kM and ks are the constants for chain transfer to amonomer and to a solvent or to a transfer agent specially introduced into the systemchains; [S] is its concentration.

It is noteworthy that the determination of the molecular masses of metallopoly-mers is faced with certain difficulties. Typically, there are no direct methods due totheir insolubility in traditional solvents. Indirect methods for molecular mass deter-mination involve metal removal from the final product (for example, by treatmentwith, or dialysis against HCl, by ion exchange, displacement by zinc amalgam,by treatment with HCl methanol solution, with sodium ethylenediaminetetraac-etate, and so on) that is followed by the analysis of the “metal-free” polymers byusual techniques (gel permeation chromatography and ebullioscopy). The molecularmasses of the polymers thus formed are most often relatively low. Thus polymer-ization of maleic acid salts (initiated by tert-butyl hydroperoxide) at 80–180 ıC for


105

106 5 Polymerization and Copolymerization of Salts of Unsaturated Carboxylic Acids

4–10 h results in the formation of a polymer with MnD 300–5;000 [1]. Probably,chain transfer reactions play a significant role in these systems. For example, inthe polymerization of tributyltin acrylate [2], it was found that the initiator, azo-bis(isobutyronitrile) (AIBN), is a more potent chain transfer agent than laurylperoxide (the relative constants for chain transfer to initiator, Kn.I//Kp, are 0.087and 0.015, respectively). It is worth noting that examples of analogous reactions forvinylic monomers are characteristic primarily for the initiators that are capable ofinducted decay, i.e., for peroxides and hydroperoxides.

5.1 Types of Initiation

In principle, radical polymerization of the salts of unsaturated carboxylic acids canbe induced by any initiator or initiating radiation. However, AIBN, benzoyl per-oxide (BP), potassium or ammonium persulfates, H2O2, tert-butyl hydroperoxide,various redox systems are used most often. The styrene–arsenic sulfide complex [3]is an example of nontraditional initiators utilized for the polymerization of metalacrylates. The complex presumably decomposes in a polar medium according tothe donor-acceptor mechanism to give the H� radical as depicted in the followingscheme:

CH=CH2

+ As2S3

CH=CH2 .... As2S3

CH=C H .... As2S3C =CH2

. . . . As2S3

+ H˙

A B

The formation of more stable tertiary radical A is probably the preferred route.The suggested scheme agrees with the data from EPR spectra of the reaction poly-merizing mixture .g D 1:9572/. Kinetic parameters (see below) are in accordancewith the classical equation of radical polymerization that is also attested by the lin-ear correlation of viscosity of the polymer upon the concentration of an initiator,� D f .ŒI�0:5/.

5.1 Types of Initiation 107

Chelated complexes of alkylcobalt with tridentate Schiff bases appeared to beefficient initiators of the low temperature radical polymerization of some metalacrylates [4]:

R

NH2

NH2CoIII

N

O Br–

+

[RCo(7-Me-salen)(en)]BrR = Me, Et, i-Pr

H2N

Complexes of this type are known [5] to generate free alkyl radicals under mildconditions upon acid treatment. Polymerization of magnesium, zinc, barium, andlead acrylates (MAcr2) induced by these organocobalt initiators proceeds at 5–10 ıCeven in the absence of acidic additives. Apparently, the function of acidic reagentsin these reactions is played by the monomers themselves for which the degree ofdissociation .105�Kd/ in methanol is rather high: at 20 ıC it is equal to 3.2261075,3.1561075, and 2.6061075 for the Zn, Pb, and Ba salts, respectively [6]. The MACcations formed can be coordinated by ethylenediamine giving rise to the active formof the initiator:

MeOH[RCo(7-Me-salen)(en)]+ + MA+ [RCo(7-Me-salen)(MeOH)2]

+ + M(A)(en)+ (5.3)

k1

k–1

[RCo(7-Me-salen)(MeOH)2]+ R

. + [Co(7-Me-salen)(MeOH)2]

+ (5.4)

The observed dependence of the rate of polymerization upon the nature of a metalin the acrylates changes in the series Zn > Mg > Ba, which is in line with thesuggested mechanism of free radicals formation. That is it correlates with the acidityof the M2C cation.

As expected, the obtained metal polyacrylates had higher molecular masses andhigh syndiotacticity (see below).

Polymerization of metal carboxylates in the solid state [7–10] and under matrixdevitrification conditions [11] is often initiated by ”-radiation. Owing to relativelylow activation energies for the formation of free radicals, the radiation initiation iseffective over a broad temperature range, especially at low temperatures. For exam-ple, the overall activation energy for emulsion polymerization of sodium acrylatein the presence of K2S2O8 is equal to 94.8 kJ/mol, whereas for 60Co ”-inducedpolymerization this value is equal to 16.7 kJ/mol [12].

Examples of photo-induced polymerization are known as well. Tetraethoxyti-tanium(IV) methacrylate derivatives are successfully polymerized in thin layersor on the surface of a metallic substrate upon UV irradiation [13]. How-ever, photochemical initiation in solution for alkoxy derivatives of Ti(IV) withmethacrylic,p-vinylbenzoic, phenylacetic acids or itaconic anhydride appeared to


be less effective due to the high absorbance of Ti(IV) compounds in UV area [14].Note that the metallopolymers obtained using UV irradiation have a more regularmolecular packing compared to the thermally initiated reaction products, as it wasobserved in the Langmuir–Blodgett films based on cadmium octadecylfumarate ormaleate [15]. The polymer formed had the same orientation of the aliphatic part ofthe chain irrespective of the double bond configuration in the starting monomer:

C

O O

HC

HC

C

O

CO O

HC

HC

O

Cd2+ Cd2+

CO O

HC

HC

C O

O

C

O O

HC

HC

O

UV

O C O C O

(CH2)17 (CH2)17 (CH2)17 (CH2)17

H3C H3C H3C H3C

Photo-induced polymerization (�D 365 nm, photo initiator – ’; ’-dimethoxy-deoxybenzoin) of liquid-crystalline metallomonomers with terminal acrylategroups, gave a good yield of highly oriented anisotropic polymers (up to 80%)with quantitative content of the metal [16].

Controlled radical polymerization in the presence of catalytic amounts of transi-tion metal halides by the atom transfer radical polymerization (ATRP) mechanismhas been actively developed in recent years [17–19]. These controlling additivesare capable of reversible interaction with reactive radicals in the reaction systemto give labile adducts, thus creating conditions for “living-chain” radical polymer-ization. Initiation of all chains takes place almost simultaneously due to the highspeed of the process. This gives rise to polymers with polydispersity being closeto unity. The first example of ATRP for the metal-containing monomers has beenreported for sodium methacrylate. The process occurs in an aqueous solution at90 ıC in the presence of a macroinitiator based on poly(ethylene oxide), copper(I)bromide catalyst and 2,2-bipyridine in a 2:2:5 molar ratio [20]. At pH < 6, thereaction was ineffective, which may be due to protonation of bipyridine and thelack of solubility of the catalyst under these conditions. The resulting poly(ethyleneoxide-block-sodium methacrylate) copolymer had a relatively low molecular massand narrow polydispersity (1.2–1.3). Recently a similar method has been used tocarry out polymerization of sodium methacrylate on the surface of various sub-strates modified by an initiator of ATRP polymerization [21, 22]. This proceduregives polyelectrolyte layers of controlled composition, thickness, and density.

There are virtually no available data on the initiation of anionic or cationic poly-merization of the considered monomers. To our knowledge, only one example ofanionic polymerization of sodium methacrylate upon the action of phenylmagne-sium bromide at �5 to �2 ıC has been reported [23].

5.2 Kinetic and Stereochemical Effects 109

5.2 Kinetic and Stereochemical Effects

The presence of a metal in molecules of the salts of unsaturated acids results incarrying various coordination reactions and redistribution of electron density on thegrowing center thus defining all elemental steps and specifics of the polymerizationprocess as a whole.

5.2.1 Radical Polymerization of Alkali and Alkaline Earth MetalSalts of Unsaturated Carboxylic Acids

The main data on the polymerization of these monomers are comprehensivelypresented in a monograph [24]. Let us consider only a few most characteristic ex-amples. For the discussion of their polymerization distinctions a hypothesis of thekinetic role of ionic pairs in the radical polymerization of the ionizing monomerscould be applied. The hypothesis was formulated and developed in a monograph[25]. According to this hypothesis, at the pH > 7 the chain propagation rate is de-termined only by the rate of the reaction of macroradicals with the terminal ion pair.The observed kinetic effects are interpreted from the standpoint of change in theeffective reactivity of the macroradicals: the growing ionized macroradicals are ei-ther separated ion pairs or ionic associates. Within the framework of these views,in the polymerization of metal-containing monomers the metal cation apparentlyacts as a counter ion, the nature of which (the charge, the electrostatic and crys-tallographic radii, solvation ability) affects the stability of ion pairs and the chainpropagation rate:

~CH2 C.

CH3

COO– COO–

C

CH3

CH2

M+

One of the first quantitative studies of polymerization of magnesium, strontium,barium, and calcium acrylates was performed in 1955 [26]. The effects of concen-trations of the monomer, and the K2S2O8�Na2S2O3 initiating system as well astemperature on the yield of the polymerization product of Ca.O2CCHDCH2/2 werestudied (Fig. 5.1).

The rate constants .2kdf / and the activation energy for initiation of radical poly-merization of lithium methacrylate at 333, 338, and 343 K were estimated usinginhibition by a stable radical, N; N -diphenyl-N 0-picrylhydrazyl, and were foundto be 3.30 ˙ 0.02, 6.19 ˙ 0.21, and 14.31 ˙ 0.60 � 10�5 s�1 and 134.2 kJ/mol,respectively [27]. Polymerization of magnesium, calcium, and strontium acrylatesinitiated by ammonium persulfate was studied [28] and the maximum polymeriza-tion rates .Wp � 106 mol l�1 s�1/ were found to be 160, 433, and 400, while themolecular masses of the resulting polymers .MM � 10�3/ equaled 92.5, 848, and990, respectively (Fig. 5.2).


Fig. 5.1 Yield of calciumpolyacrylate vs. monomer (1)and initiator concentration (3)and vs. polymerizationtemperature (2)

P, %

96

92

88

84

2

2

10 20 30

4 6 10

22 42

1

23

T, °C

CI, %

CM, %

100

a

c

bP (%)

80

60

40

20

1 2 3 t / h

100

P (%)

80

60

40

20

1 2 3 t / h

100

P (%)

80

60

40

20

0 1 2 3 t / h

1

1

1

2

2

2

3

3

3

Fig. 5.2 Yields of calcium (a), strontium (b) and magnesium (c) polyacrylates vs. time for initialmonomer concentrations of 0.2 (1), 0.5 (2) and 0.8 mol L�1 (3). Polymerization temperature,80 ıC, initiator concentration 0.25 mol%


These differences were attributed to different charge density on the macroradicalanion determining the interactions in the growing macroradical–monomeric anionsystem. The polymerization rate of sodium methacrylate in concentrated aqueoussolutions (3.15–4.67mol/l) in the presence of K2S2O8 was found to obey zero orderkinetics, that is the rate does not depend on the initial monomer concentration. Therate order with respect to the initiator is 0.51 ˙ 0.20 and the apparent activationenergy is 81.5 kJ/mol [29].

The presence of a metal in the monomer molecule does not prevent the emulsion(latex) polymerization, while in the usual emulsion, polymerization salts cause co-agulation of the latex. Emulsion polymerization of water soluble sodium acrylate inreverse micelles in a nonaqueous phase follows a nuclear “monomer-drop” mech-anism, i.e., the reaction is initiated in the monomer drops because the initiator isdissolved in the internal aqueous phase [30]. The particle size of the monomer emul-sion and the resulting polymer latex are virtually the same and are equal to �1 �m.The mechanism is also supported by S-shaped kinetic graphs conversion vs. time.The maximum polymerization rate and the molecular mass of sodium polyacrylateformed are described by the following equations:

Wmax D ŒK2S2O8�0:78ŒM�1:5ŒSpan 80�0:1 and M D ŒK2S2O8��0:37ŒM�2:9ŒSpan 80��0:2:

It is noteworthy that the polymerization rate and the molecular mass of the poly-mer formed in this system depend little on the emulsifier concentration (Span 80),in contrast to the case of usual emulsion polymerization. A similar dependence ofthe reaction rate, Wr, upon the monomer concentration, was observed in the photo-induced emulsion polymerization of sodium acrylate [31]. However, an increasein the concentration of the photoinitiator first causes a gradual increase in the Wr

and then a sharp decrease, while the molecular mass follows an opposite depen-dence upon the photoinitiator concentration (Fig. 5.3). This behavior of the Wr isattributed, on the one hand, to the adsorption effects of the photoinitiator and, on theother hand, to recombination of primary radicals at high concentrations.

2.2a b 10

2.0

1.8InR

p

In[In]DMPA

1.6

–16 –15 –14 –13 –12 –11

8

6

4

2

00 2 4

[In]DMPA (×10–6)

Mh

(×10

6 )

6 8 10

Fig. 5.3 Rate of emulsion polymerization of sodium acrylate (a) and viscosity average molecularmass of the polymer (b) vs. DMPA concentration


5.2.2 Radical Polymerization of TransitionMetal (Meth)acrylates

Usually polymerization of transition metal (meth)acrylates is carried out in non-aqueous media, i.e., under conditions that rule out dissociation. According toelectrical conductivity measurements [6], in ethanol and DMF transition, metalacrylates are weak electrolytes .Kd D .1:97 � 2:25/ � 10�5/ and under the exper-imental conditions, where the monomer concentration is 10�3� 10�1 mol/l, theirdissociation can be neglected. Thus, polymerization of chromium(III) acrylate inDMF in the presence of styrene–As2S3 complex follows a radical mechanismand has the orders of 1.0 and 0.5 with respect to the monomer and the initiator,respectively (Table 5.1) [3].

Table 5.1 Kinetic parameters of polymerization of metal (meth)acrylatesOrder of reaction

MonomerPolymerizationconditions

kp2=kt 103

(L/mol s)With respectto monomer

With respectto initiator Ea (kJ/mol) Ref.

Chromium (III)acrylate

DMF, 90 ıC,initiator –Sterol-As2S3

31.0 1 0.5 67.0 [3]

Cobalt(II)acrylate

DMF, AIBN,65–75 ıC

0.84–1.74a 1.27 ˙ 0.06 0.54 ˙ 0.04 74.0 ˙ 2.3 [33]

Cobalt(II)acrylate

EtOH, AIBN,78 ıC

0.9 0.6 [36]

Nickel(II)acrylate

EtOH, AIBN,78 ıC

0.56–1.40a 1.21 ˙ 0.09 0.53 ˙ 0.05 89.3 ˙ 3.2 [33]

Zinc(II)acrylate

EtOH, AIBN,78 ıC

4.95–10.28a 1.49 ˙ 0.10 0.86 ˙ 0.06 71.6 ˙ 3.5 [34]

Sodiumacrylate

H2O:kerosene D1.5:1 (vol.),50 ıC, 9.8 MK2S2O8, pH7.02,13.3 wt%Span 80

1.5 0.78 94.8 [12]

Sodiummethacrylate

H2O, 3,15–4.67 mol/L,K2S2O8

0 0.5 91.5 [29]

Tributyltinacrylate

Decane:benzeneD 90:10 wt%,laurylperoxide

1.05 0.49 [2]

Tributyltinacrylate

Decane:benzeneD 90:10 wt%,AIBN

1.10 0.45 [2]

aK � 103; K D .2kdf=kt/0:5kp, L1=2=mole1=2 s


Fig. 5.4 The effect of type oftransition metal on the rate ofmetal acrylates: Zn2C (1),Co2C (2), Ni2C (3), andCu2C (4)

P, %

80

1

2

3

4

60

40

20

0 6 12 18 time, h

Table 5.2 The rate constants and activation energy of the initiationreaction of transition metal acrylates polymerization [35]

2kdf � 105 .c�1/

Metal acrylates 343 K 353 K Ea; 2kdf (kJ/mol)

Zn(II) 2:93 10.6 128.2 ˙ 1.1Co(II) 2:93 7.90 116 ˙ 1.5Ni(II) 2:62 9.52 129.8 ˙ 0.3

Zinc(II), cobalt(II), nickel(II), and copper(II) acrylates show different reactivi-ties in methanol in the presence of AIBN [32–34]. The polymerization rate of zincacrylate is the highest, the long induction period being followed by fast exothermicreaction (Fig. 5.4).

For other salts, no induction period was observed. Copper acrylate polymerizesin a low yield. Studies of the initiation rate of polymerization have shown that thevalue for the rate constant, 2kdf , vary in the series of acrylate salts in the orderZn2C > Ni2C > Co2C. Hence, the activation energy of initiation varies in the sameway (Table 5.2) [35].

For the cobalt(II) acrylate, the value of Ea; 2kdf (116 ˙ 1.5 kJ/mol) is signif-icantly lower, which is in line with the variation of the overall activation energyof polymerization in the series of these monomers (Table 5.1). This decrease in theactivation energy for initiation reaction for cobalt(II) acrylate is attributed to the pos-sible formation of the complex Co2C: : : AIBN, though no experimental evidencessupporting this view were presented by authors. Under the comparable conditions(AIBN, ethanol), the rate of radical polymerization of transition metal acrylates is


Fig. 5.5 The dependence ofreaction conversion on thetime of polymerization foracrylic acid (1) and metalacrylates: Co2C (2), Ni2C

(3), Fe3C (4) and Cu2C (5)(CM D 0:9 mol=L; CAIBN D2:5 � 10�2 9 mol/L, ethanol,78 ıC)

100q, %

1

2

3

4

5

60

20

0 20 60 100MИH

lower than the rate of homopolymerization of acrylic acid (AA) (Fig. 5.5), decreas-ing in the series of cations Co2C > Ni2C > Fe3C > Cu2C [36, 37].

Analogous behavior is characteristic for hydrogenation of these carboxylates [38]that can be caused by decreasing of electro density on the double bond, with increas-ing of electronegativity of metal. An increase in the initial monomer and initiatorconcentrations results in an increase in the reaction rate, which is in good agree-ment with general rules of radical polymerization. Polymerization of metal acrylatescomprises the same elementary steps as polymerization of conventional monomersbut it is affected by the nature of the transition metal. In view of the fact that theinitial and current concentrations of monomers (M0 and M, respectively) are relatedto the degree of conversion (˛) in the following way: [M] D [M0] .1 � ˛/, in thequasi-stationary approximation with respect to macroradicals, the polymerizationrate can be represented by the following equation:

d˛=d� D kp.ki=kt/1=2I1=2.1 � ˛/: (5.5)

Solution of this equation provided that [I]D [I0] exp(�kit) gives the dependence

lnfln.1 � ˛/C 2kpŒI0=.kikt/�1=2g D ln2kpŒI0=.kikt/�

1=2 � 1=2kit ; (5.6)

that satisfactorily describes the polymer accumulation kinetics in the liquid phaseradical polymerization of cobalt(II) acrylate [36] (Fig. 5.6).

The equation for the limiting conversion vs. the initial initiator concentration isin good agreement with the experimental data (Fig. 5.7):

ln.1 � ˛1/ D 2kpŒI0=.kikt/�1=2: (5.7)


Fig. 5.6 The graphicalsolution of the (5.6)

A D"

ln.1 � ˛/ C 2kp

�I0

kikt

�1=2#!

However, as noted above, polymerization of the carboxylates under considerationcan be accompanied by a number of transformations. For example, the coordina-tion of the monomer to the primary radicals .RC

:/ at the initiation step results indeactivation of the radicals and decreases the initiation efficiency:

(5.8)

CH2

CH2 CH2

CH

X

+ Rc.

CH

Mn.Rc.

CH + Rc+

MnX

CH

Mn

RcC H2

X Mn–1X

.

(5.9)

Obviously, the competitive binding of polymeric radicals also accompanies chainpropagation and the coordinated radicals thus formed can also undergo intramolec-ular deactivation:

R.

+ CH2 CHCH CH2 CH + R+

X

C+HC

.H

C.H

~CH2 ~CH2

~CH2

CH2

(M – metal, n – its valency, X – functional group)

X Mn

X Mn

Mn.R.

X Mn–1X

Mn–1XMn

(5.10)

(5.11)

(5.12)

The observed deviations of the reaction orders with respect to the monomer andthe initiator in these systems (Table 5.1) compared to the classical radical poly-merization may be due to these side reactions, that is to the more complicatedinitiation mechanism. For example, their increased values attest to a dependence


Fig. 5.7 The degree oflimiting conversion of themonomer vs. Initial initiatorconcentration during radicalpolymerization of Co(II)acrylate

In(1– α)

1.5

1.0

0.5

0 0.05 0.10 [I0]0.5 / mol0.5 litre–0.5

Fig. 5.8 Cu2p3=2 and C1s XPS of Cu(II) acrylate (1) and the product polymerization (2); thespectrum of Cu2O (doted line)

of the initiation rate on the monomer concentration and to an increase in the contri-bution of the monomolecular termination to the overall kinetic chain termination.

Thus, the above mentioned low polymerization rate of the copper(II) acrylate canbe attributed to the following reaction:

(5.13)X

~CH2~CH2CH C

+H

CuII X CuI

⋅

This is probably facilitated by the relatively low values of the standard reductionpotentials for copper ions. Thus, Eo Cu.II/!Cu.I/D 0:15 V, while for the compari-son Eo Cr.III/!Cr.II/D �0:41 V and Eo Ti.IV/!Ti.III/D �0:41 V. By means of specialspectroscopic and magnetochemical studies [39], it has been demonstrated thatthe reduction of some portion of copper(II) ions indeed takes place during thecopper(II) acrylate polymerization. The XPS Cu2p3=2 and C1s spectra for theCH2DCHOCO/2Cu and the product of its polymerization are presented in theFig. 5.8. The 1 eV shift of the main Cu2p3=2 peak toward lower bond energy is


observed in the result of the polymerization. Also, the relative intensity of thesatellite located at the high energy side from the main signal decreases from 0.38to 0.20. There are 2 peaks in the C1s spectrum. One, at 285.0 eV, is due to �CH3,�CH2� and �CHD groups present in the investigated compounds and vapors ofthe oil absorbed. The other peak, at 288.5 eV, is due to the carbon atom of the car-boxylate group, COO�. The half width of the main C1s signal equals 3.0 and 3.6 eVfor the CuAcr2 and the copper polyacrylate (PAACu), respectively.

5.2.3 Regulation of Stereochemistry of Radical Polymerizationof Metal Carboxylates

It is known that the problem of the stereospecific synthesis under the radical poly-merization relates to the slight differences between the activation energy for thereaction rates for the growth of isotactic .ki/ and syndiotactic .ks/ sequences. Thedifference between the corresponding activation energies equals about 1 kcal/mol.In accordance with the expression

ki=ks D e��.�F ¤/=kT ; (5.14)

where �F ¤ D �F¤i ��F

¤s is the difference between the free activation energies

for iso- and syndiotactic additions. The microstructure of the polymeric chains inthe radical polymerization should be affected by factors that can change the ratio ofthe constants for the iso- and syndiotactic additions for the growth reaction. First ofall, this is low polymerization temperature, because the predominant formation ofthe syndiotactic conformation with respect to the isotactic one is mainly due to theenthalpy factor. Steric hindrance and polarity also promote the directed growth ofthe polymer chain. According to the ion pair mechanism and the corresponding cal-culations, it was shown that the formation of the growing radical – counter ion pairsis accompanied by preferred syndiotactic addition. Polymerization of the salts ofunsaturated carboxylic acids creates certain prerequisites for the formation of regu-lar polymers. Apparently, owing to the presence of the polarized metal carboxylategroup, the growing center changes its stereochemical configuration to the oppositeone in every chain elongation step. As a result, configurations of the carboxylateunits in the polymer alternate. The particular role is played by electrostatic inter-actions between the ionized growing radical and the polar metal containing group.Also, the coordination bonds of the metal cation can have a directing effect. In theearliest publications it was shown [40], that the radical polymerization of alkalimetal methacrylates carried out in water gives mainly syndiotactic polymers (thecontent of the syndiotactic fraction ranges from 90 to 95%). The anionic polymer-ization of sodium methacrylate affords the polymer containing 78.2–97.8% of theisotactic fraction [23]. Meanwhile, the radical polymerization of this monomer at70 ıC in benzene yields a polymer with the ratio of the syndio- to hetero- formsof 72.1–26.2. Moreover, even a relatively low content of (meth)acrylate salts in


their copolymers allows effective control over the microstructure of the polymersformed. Thus, in the triple copolymers MMA–MAK–sodium methacrylate [41], thesalt content in a 0.1–0.5 mol% range results in an increase in the number of alter-nating dyads (Table 5.3) and gives more sterically ordered products. This is madeevident by the appearance of isotactic configurations and higher concentration ofsyndiotactic triads as their fraction increases with the increase of the concentrationof salt groups.

It is worth noting that the content of syndiotactic units in the growing polymericchain may be determined by the nature of the counter ion, its sorption ability, thepolarity of the medium and so on. For example, bulk radical polymerization of trib-utyltin methacrylate (TBTM) gives a polymer structure similar to that of the macrocomplex resulting from the reaction of [(BuO)3Sn]2O with atactic polymethacrylicacid (PMAA) [42] (Table 5.4).

Apparently, this is related to polymerization conditions: in bulk polymerization,the effect of ion pairs is less pronounced than in polymerization in polar solvents.This was confirmed by polymerization of cobalt and nickel acrylates in ethanol at60 ıC and their radiation induced low temperature polymerization on defrosting ofglassy matrices [11, 36].

After hydrolysis of the resulting metallopolymers, up to 60–65% of syndiotac-tic polyacrylic acid (PAA) was isolated (the fraction soluble in a dioxane–water(80:20) mixture). Note that the microstructure of the metallopolymers formed uponpolymerization of (meth)acrylates of divalent metals (bifunctional monomers) isdetermined by both the structure of the active site, the reaction temperature, andthe nature of the solvent as well as by the steric factors of the spatial cross-linked

Table 5.3 Microstructure of copolymers of MMA with methacrylic acid and sodiummethacrylate [41]

Concentration of sodiummethacrylate (mol%)

The number of theMMA-MAA diad (%)

Concentration of triada (%)

i h s

0 37 0 45 550.10 50 4 36 600.25 52 9 28 630.50 54 11 24 65ai is isotactic, h is heterotactic, and s is syndiotactic configurations

Table 5.4 The stereo regular composition of tin-containing polymers [42]

Tacticity (%)

Macrocomplex Iso- Syndio- Hetero-

Iso-PMAAC[(BuO)3Sn]2O 100 0 0

Syndio-PMAAC[(BuO)3Sn]2O 0 78 22

Atactic PMAAC[(BuO)3Sn]2O 15 44 41

Atactic PMAAa 6:5 56:5 37:0

Product of TBTM polymerizationb 18 50 32

aPolymerization in toluene, BP initiatorbPolymerization in bulk, AIBN initiator, at 60ıC


Table 5.5 The stereoregular composition of PAA isolated from metal polyacrylates

The yield of fraction (%)

The starting polymer Soluble in dioxan (atactic)Soluble in the mixture ofdioxan-water (syndiotactic)

Zna polyacrylate 20 80Znb polyacrylate 58 42Polyacrylic acidb 59 41Baa polyacrylate 26 74aPolymerization at 9 ıCbPolymerization at 70 ıC

metallopolymer structure. Indeed, low temperature radical polymerization of zinc,barium, and lead acrylates affords a higher content of the regular fraction, as in-dicated by the fractionation data for PAA isolated from these metallopolymers(Table 5.5) [4].

According to a known scheme [43], the process of polymerization of bifunctionalmonomers can be conventionally divided into two stages. The first stage yields acomb shaped linear polymer. Apparently, stereo regular fractions are formed duringthis period. The second stage includes the formation of a three-dimensional networkstructure, as chain propagation reactions involve mainly the CDC bonds of the sidechains of the macroradical. At this stage chain growth takes place under high stericstrain and is accompanied by an increase in the internal stress, giving rise to anatactic structure of polymer chain.

MM M M

M MM

M M M

M M M

MM M

R.

Thus, the data of the low frequency IR spectra of metal polyacrylates [4] show thatin the region of �O�M�O� vibrations the spectrum of the polymer exhibits onebroad band with a maximum at 340 cm�1 instead of two narrow bands (at 300 and400 cm�1) typical for the metal-containing monomer. This is a consequence of dis-tortion of the geometry of bridging groups caused by internal stress in the networkstructure. Moreover, in some cases, these two stages can be separated kinetically, ashas been demonstrated recently in a study of thermal transformations of Co(II) acry-late by dielectric spectroscopy in situ [44]. Figure 5.9 presents the dependence of therelaxation time, �m.T /, vs. Arhenius units. It can be seen that till region 3, the spec-tral pattern is typical for relaxation processes, i.e., the relaxation times decrease withan increase in temperature. The occurrence of polymerization in the region 1 is con-firmed by the deviation of the experimental �m.T / values from the theoretical ones.


Fig. 5.9 Relaxation time �m

in the polymerization ofcobalt (II) acrylate vs.temperature (The points arethe experiment and the curveshows the results ofcalculation).(1) polymerization region,(2) ’-relaxation region,(3) cross-linking region

On further increase in temperature, the experimental and theoretically calculateddata approach each other. At higher temperatures, polymerization involving theresidual double bonds apparently takes place, i.e., a cross-linked polymer is formed.

The topochemical factors are also crucial in the formation of isotactic oligomersin the solid phase polymerization of zinc 3-butenoate [45]. Unusual stereo- andregiospecific effects were discovered for other alkenoates as well. The ”-inducedstereospecific trimerization of the sodium trans-2-butenoate results in the formationof one of the eight possible diastereomers, namely, the trisodium 2,4-dimethyl-6-heptene-1,3,5-tricarboxylate [46]:

CO2Na

CO2Na CO2Na CO2Na

γ -rays*

*

*

*2345

Under similar conditions, Ca(II) trans-2-butenoate is subjected to cyclodimeriza-tion yielding only one diastereomeric form [47].

O

OCa

2

γ-rays

60ºC, 24 h

CH3

CO2Ca

CO2Ca

**

*1

23

When the kinetic effect of the polarized metal carboxylate group is clearly ob-served, it is possible to obtain crystalline metallopolymers. Thus, the degree ofcrystallinity of iron(III) polymethacrylate synthesized by ”-induced polymerizationdepends on the radiation dose. The highest degree of crystallinity (39%) is obtainedin the range of 10–25 kGy, although no clear trend for increasing or decreasing ofthis value with the dose increase was found [48].

The photopolymerization of liquid-crystalline metal carboxylates contain-ing terminal acrylate groups [16] produces anisotropic polymers. The resulting

5.3 Solid Phase Polymerization of Unsaturated Metal Carboxylates 121

Fig. 5.10 Maximumphotopolymerization rate (1)and conversion (2) of theliquid crystal monomerZn(O2CC6H3(O�(CH2/11�OCOCHDCH2/2/2

vs. temperature

W max (% s–) α (% )

0.8

0.6

0.4

0.210 20 30 40 50 60

0

10

20

30

T / °C

1

2

metallopolymers have a hexagonal columnar structure that was confirmed by X-raydiffraction. The mesormorphic structure of the monomer is not changed signifi-cantly during polymerization, although the hexagonal packing is compressed forthe polymer. The column-to-column distance in the polymer is 33.7 A instead of39.2 A observed in the monomer. Note that the maximum reaction rate and thedegree of conversion increase with temperature in the region of existence of thefolded mesophase of the monomer .45–55 ıC/ and decrease in the isotropic phaseregion at 65 ıC (Fig. 5.10). The observed kinetic effects are likely related to orderingof the structure and self-assembling of the polymerizing metal carboxylate in themesophase, on the one hand, and loss of orientation of the monomer in the isotropicphase, on the other hand. Similar effects were also observed for the traditionalmonomers [49–51].

5.3 Solid Phase Polymerization of UnsaturatedMetal Carboxylates

As has been noted, polymerization of this type of monomers in solutions can beaccompanied by dissociation of salts, particularly salts of s-elements. Another dis-advantage is a limited number of solvents that allow preparation of concentratedenough solutions to carry polymerization. Yet the majority of metal carboxylatesare solids (crystalline or amorphous) at room temperature, thus allowing to utilizemethods of solid phase polymerization. Metal carboxylates are also most oftenconvenient objects for solid phase polymerization from the structural chemicalaspect, since the orientation of their molecules is optimal for formation of chem-ical bonds between them. Chain propagation takes place in the plane of stacks oftightly packed monomer molecules parallel one to another. Such a process doesnot take place in either liquid or vitreous state. Therefore, there is no need forsignificant change in the location of carboxylate molecules in crystals for the solid


phase polymerization. Regardless of the method of initiation of the solid phasepolymerization, the following premises are put [52] into the base of its kineticscheme: space movements of the growing macroradicals and their collisions withmonomer molecules occur only as a result of chain propagation acts (because ofalmost full absence of onward diffusion of the reacting particles); irregularities ofa crystalline lattice (dislocations, cracks, vacancies, and so on) are the breakingpoints of the growing chains; anisotropy in reactivity of macromolecules growingin a crystalline lattice defines their growth predominantly along one of crystallo-graphic axes. The process of initiation of the free radical (sometimes of the ionic),polymerization of unsaturated metal carboxylates in the solid state, can be started bydifferent types of initiation. The most often used types are thermal, photochemical,and radiation, also mechanochemical one is rarely used.

5.3.1 Thermal Polymerization of Unsaturated Metal Carboxylates

Examples of thermal generation of free radicals upon solid phase polymerizationof metal carboxylates are rare and mainly involve acrylates of transition metals.Free radicals initiating the polymerization are formed in a result of either the dis-association of C�C or C�H bonds or the opening of a double bond (formation ofbiradicals). The rate of solid phase polymerization increases with temperature, sincethere is a need for higher amplitude of thermal vibrations, so the reactive centers canget closer. Thus, thermal polymerization of sodium acrylate occurs at 145–175 ıCin vacuum [53]. Activation energy for the initiation (determined from EPR data)equals 121 kJ/mol. The process takes place with an induction period that decreaseswith an increase of temperature (Fig. 5.11) (Ea equals 115.5 kJ/mol, that is in agree-ment with the value found from the EPR data), and the chain propagation stage hasEa D 68:9 kJ=mol.

Barium methacrylate, Ba.OCOC.CH3/DCH2/2 H2O, is one of the first metalcarboxylates, with which solid phase polymerization was investigated [54].

Fig. 5.11 Yield of sodiumpolyacrylate vs. time attemperatures 145 (1), 157 (2),166 (3) and 175 ıC (4)

30

43

2

120

10

0 40 80 120 160 Time, min

P, %


Dehydration of this monomer .65–140 ıC/ is accompanied by the formation ofvarious particles of radical nature [55] that can initiate polymerization. Decompo-sition that starts at 210 ıC becomes significant at 400 ıC. At this temperature rangebarium and calcium .300–350 ıC/ methacrylates form di-, tri-, and tetramers [56].The mechanism of their formation has clearly been identified and the correlationbetween the structural aspects and the ability to polymerize was found for thosemonomers [55].

Decomposition of methacrylates and maleates of d -elements is preceded bytheir thermal polymerization [57–66]. Investigations of the transformation of themonomers under either TA conditions, or in the self generated atmosphere revealedthat in the temperature range 200–300 ıC small gas formation occurs along with in-substantial mass loss of the sample (�10 mass%). In the case of metal acrylates andmaleates major contribution is made by CO2 and the vapors of CH2DCHCOOHand HOOCCHDCHCOOH, respectively, that condense on reactor walls at roomtemperature. This is supported by IR and mass spectrometry data. According to theTA data the characteristic temperature polymerization areas are: �270 ıC (Co(II)acrylate), �290 ıC (Ni(II) acrylate), �237 ıC (Cu(II) acrylate), �310 ıC (Fe(III)oxoacrylate), 215–245 ıC (Co(II) maleate), �245 ıC (Fe(III) maleate). During thepolymerization changes in the IR absorption spectra take place. These are relatedto the intensity decrease of the absorption band for the CDC bond valent oscilla-tion and closing absorption bands for the CDO bond valent oscillation, resulting inemerging one broaden absorption band at 1,540–1,560cm�1. Similar peculiaritiesare notable for polymerization both in solution (see Sect. 4.2) and in solid state: highreactivity is observed for Zn(II) acrylate, as well as for Co(II) and Ni(II) acrylatesand low reactivity is noted for Cu(II) acrylate.

5.3.2 Solid State UV and Radiation Initiated Polymerization

Photochemical initiation of metal carboxylates polymerization in solid state can berealized rather rarely. One of a few examples is efficient photopolymerization ofpotassium acrylate [67] (UV irradiation with wave length 250–300 nm): yield of thepolymer is 40% at 73 ıC, however, its molecular mass decreases with the increase ofconversion (from 4.7 � 105 to 2.2 � 105). Photo initiated polymerization of calciumacrylate [68] proceeds with constant rate till high degrees of conversion.

Radiation initiation at low temperature is a universal method for initiation ofsolid state polymerization of unsaturated metal carboxylates. In essence this is theirradiation of the salts at low temperature (typically at the temperature of liquidnitrogen or at �78 ıC) with ”-irradiation of 60Co, fast electrons, or X-rays (seldomwith low temperature plasma). Since under these conditions chains do not grow,there is an accumulation of radicals (or other active centers) in the samples for thefollowing postpolymerization at ambient (or higher) temperature.

Relatively early studies reported [69] an easily proceeding polymerization ofacrylate salts of Rb and K in vacuum at room temperature (irradiation at �78 ıC),


while Na and Li salts required heating to 150 ıC. The fastest polymerizing MSM ispotassium acrylate: it polymerizes faster at 0 ıC (Ea D 70 kJ=mol) than the sodiumsalt does at 120 ıC. Chain length of potassium acrylate is higher by an order ofmagnitude than upon polymerization of the Na or Li salts. Interestingly, the reversereactivity order was observed for methacrylate salts. Sodium methacrylate is moreactive than the potassium salt, while lithium methacrylate is not active at all. Thesedifferences are attributed to the geometry of crystal lattices of the correspondingsalts, which in turn is defined by the nature of a metal ion.

Correlation of the mobility of acrylate ions with the rate of their radiationpostpolymerization has already been pointed out above [70]. The minimal val-ues for the rate constant for radicals death are observed for potassium acrylate((2.92 ˙ 0.89) � 10�3 s�1) and rubidium acrylate ((2.28 ˙ 0.14) � 10�3 s�1)at temperatures close to those of phase transfers (at 61 ıC and 47 ıC, respec-tively). The initial rate of polymerization of Ca2C, KC, and Ba2C acrylatesis 18.1; 56.8 and 75.1%/h under comparable conditions. Polymerization of theCa.OCOCHDCH2/2�2H2O is rather peculiar as the polymer yield depends on thedegree of hydration of the salt [71]. The water from dihydrate was removed at60 ıC in vacuum and conditions for the solid state polymerization were as follows:I D 0:97 J=.kg s/; D D 8:6 kJ=kg; �78 ıC, postpolymerization at 25 ıC during9 days. Utilization of the half hydrated form gave rise to the highest yield of thepolymer. In the case of barium methacrylate the maximum rate of polymerizationwas when the substance contained 0.25 mol of water per 1 mol of the salt [72]. Thestructure of that salt is thought to be crumbly with a number of dislocations that fa-cilitates the solid state polymerization. Hydrogen atoms forming from the hydratedwater upon the radiolysis of the salts hydrates contribute significantly to the genesisof free radicals initiating solid phase polymerization. The EPR spectrum of the”-irradiated barium methacrylate dihydrate is attributed to the radicals generatedaccording to the following scheme [73, 74]:

H + CH2 C

CH3

CH3

CH3

COO− COO−C.

Those initiating radicals compose up to 90% of the forming radicals, the rest 10%are growing radicals of the RCH2C:(CH3)COO� type. Experiments with D2O con-firmed that up to 75% of the initiating radicals of the monohydrate are formed viaaddition to double bond of hydrogen atoms generated from the hydrated water. Theoverall yield of the radicals increases linearly with the irradiation dose, while thepolymerization rate is proportional to �[I]1=2, Ea D 132 kJ=mol [75]. Importantly,that the crystal anhydrous salt yields only less than 2% of polymer even after highirradiation doses and long heating (Figs. 5.12 and 5.13). Additionally, the growingradicals on polymerization of dihydrate have a conformation that is different fromthe one of monohydrate. According to X-ray analysis data [76] the crystal structureof Ba.OCOC.CH3/DCH2/2�2H2O significantly transforms during polymerization.The observed induction period for the polymerization is due to physical captureof short chain growing radicals and its duration substantially decreases upon the


Fig. 5.12 Product yield ofBa.OCOC.CH3/DCH2/�2H2Opolymerization vs. time at�78 ıC; the doses ofradiation (kJ/kg) 40 (1), 20(2), 10 (3) and 5 (4)

75

4

3

2

1

50

25

0 2 4 t, cyn

P, %

Fig. 5.13 The influence ofwater excess on the yield ofpolymer at 50 ıC: (1) bariummonohydrate; (2) humidmonohydrate;(3) monohydrate C5% H2O

1

2

375

50

25

0 2 4 t, cym

P, %

increase of temperature or power of the dose. Simultaneously, according to spec-troscopy data [77] the oxypolynuclear structure of Al(III) oxo methacrylate does notincur any significant changes upon 60Co ”-induced polymerization at room temper-ature and various doses (10–50 kGy):

γ-radiation[Al(OH)x(OH2)y(OOCC(CH3)=CH2)z] {Al(OH) x(OH2) y[OCC(−C(CH3)CH2)−)z]}n

(5.15)

In contrast to the features discussed above, Zn.OCOC.CH3/DCH2/2 exhibits a par-ticular capability toward radiation thermal polymerization (the crystals were groundand irradiated at �78 ıC) at 89:5 ıC, and its deceleration occurs at well below theTm of the monomer. Among a few reports on the ”-initiated solid phase polymeriza-tion of acrylates of d -elements the high tendency of Fe(III) methacrylate [48,78,79]to polymerize .I D 0:83 J=.kg�s/; D D 45 kJ=kg/ is worth noting.

5.3.3 Reactivity of Unsaturated Metal Carboxylates in Solid Phase

As we mentioned above, it was demonstrated in the earliest works [55, 69, 73, 76]that reactivity of various salts containing the same monomeric anion is controlled bythe geometry of the crystal lattice. Thus, the parameters of elemental orthorhombic


lattice of potassium acrylate (a D 20:5, b D 4:15, and c D 5:73 A) presume an in-definite chain of reactive centers within a distance of �4.15 A. This correlates withthe main topochemical postulate that reactive groups capable of undergoing solidphase dimerization or polymerization must be located within distances of �4.2 Afrom one another [80–82]. Interconnection between crystal structure and reactivityin solid phase is well documented for a wide range of metal carboxylates includingpropionates, trans-2- and 3-butenoates, trans-2-pentenoates of metals. The presenceof a metal mostly plays a definitive role in the activity of ’; “-unsaturated carboxylicacids in solid phase polymerization reactions, by taking into account other factors,such as relative distances between active centers, energy of the crystal lattice, crosssection of absorption uptake and so on. Thus, under an influence of an ionizing ir-radiation crystal metal (Na, K, Rb, Mg, Zn, Cd, Sr, Ba, La, Sc) propionates [83]yielded 23–97% of dark colored polymer products. In contrast, metal free organicacetylenes under analogous conditions display low reactivity in solid phase trans-formations despite advantageous special orientation of acetylenic centers [84–86].Heavy metal salts exhibit especially high sensitivity toward ”-irradiation. The pres-ence of a chain of short contacts of acetylenic groups (3.454 A) in the molecule of.CH3/2Tl.OOCC�CH/ facilitates its efficient polymerization under 60Co ”-rays.This is evident by the correspondent loss of intensity of �C�C� valent oscilla-tion at 2,080 cm�1, and the yield for the product linearly increases with an increaseof irradiation dose in a range of 7–21 Mrad [87]. Analogous peculiarities were ob-served during solid phase polymerization of scandium(III) propionate [88]. Chainsof indefinite �C�C� � � ��C�C� contacts C(2)–C(3) [z, x, y], 3.79 A and C(2)–C(3) [1=2 � z, x � 1=2, y], 4.02 A are in orthogonal positions, i.e., in this case,the criterion for parallelism of short contacts of active centers is not a requiredcondition for a topochemical reaction, as it was for postulated alkene derivatives[82]. This structural difference is also characteristic for other propynoates [89]. Inaddition to the mentioned factors, the nature of accompanied ligands plays an im-portant role in the reaction behavior of carboxylates of the type considered. This canbe illustrated by an example of two complexes, La2.OOCC�CH/6.H2O/4 � 2H2Oand La2(OOCC�CH)6(2,2-bipy)2(H2O)2�4H2O�2(2,2-bipy) [90], having similarmolecular structure, but differing in spatial packing. There is an indefinite chainof acetylene contacts with a distance of 3.95 A in the former compound, while thereare C’�C“ contacts consisting from only five �C�C� � � ��C�C� sequences inthe latter one. In accordance with the observed differences in crystal structure of thecomplexes, the La2(OOCC�CH)6(H2O)4�2H2O polymerizes efficiently on 60Co”-irradiation yielding 59% of polymeric product at 65 Mrad, while the complexwith 2,2-bipy ligands appeared to be stable toward ionizing irradiation and did notpolymerize in these conditions.

Two-layer motif in structural organization is a characteristic feature for manymetal alkenoates. First of all this is typical for the monomers that contain metalatoms with small radii. The two-layer arrangement of organic groups facilitatesappearance of parallel unsaturated groups, with short distances between reactivecenters. Inorganic and organic domains can be identified in the structure of lithiumsalt of trans, trans-2,4-hexadieneoic acid, CH2DCH�CHDCH�CH2COOLi,


Fig. 5.14 Two-layered motif of crystal structure of Li sorbate (a) and inorganic Li�O tetrahedronlayers of the molecule (b)

[91] (Fig. 5.14). The inorganic part of the structure consists of an indefinitetwo-dimensional chain of Li�O tetrahedrons connected by caps and edges. Sorbategroups form organic layers in planes that are almost parallel and arranged in azigzag fashion. These planes are not fully planar, the torsion angle between car-boxylate and the first vinylic group being approximately 10ı. The shortest distancesbetween potential reactive centers found in the structure, i.e., between unsaturatedcarbon atoms, are 3.66 and 3.80 A, belonging to ˇ � ı and ˛ � � contacts or 4.12 A(˛ � ı contacts). Thermal initiation of the lithium sorbate in the temperature range220–285 ıC (24 h, vacuum) gives rise to an amorphous polymer with 100% yield. Inthe case of X-ray induced reaction (Cr-irradiation, 40 kV) completely polymerizedproduct is also amorphous though the (111) reflexes on a X-ray spectrum remainrather sharp, i.e., distraction of a crystal structure during the polymerization is notisotropic. Apparently the polymerization takes place primarily along the ˛ � ı

direction since these contacts are localized in the (111) layer.The topochemical polymerization of benzylammonium muconate is another ex-

ample illustrating that the crystal structure of a precursor monomer can be retainedduring a solid state reaction [92, 93].

hνn

CO−

2N+H3C6H5 CO

−2N

+H3C6H5

CO2NH3C6H5 CO2NH3C6H5

A layered structure of the polymer crystal obtained reproduces the structureof benzylammonium monomeric crystal consisting from alternating packed lay-ers of the diene carboxylate anion and the benzylammonium cation supported bytwo-dimensional network of hydrogen and CH� bonds. This is evidenced by thecharacteristic diffraction of the polymer product at 2 D 5:2ı .d D 17:0 A/.

Salts of less reactive “,”-unsaturated carboxylic acids, such as Zn(II) [45] andCa(II) [8] bis(3-buteneoates) also reveal a capability to solid state polymerizationdue to parallel orientation of unsaturated groups. Interestingly, that in the structure


of the Zn(II) salt one set of buteneoate groups is arranged almost parallel with adihedral angle 9:1ı and the distance between the unsaturated centers C(3)–C(4).x;�2 � y; z � 1=2/ 4.21 A, while the groups in another set are separated by 4.42 A(C(7)–C(8) .x;�2 � y; z � 1=2/ with a dihedral angle 119:0ı. The latter groupsappear to be inactive upon the ionizing irradiation, and the maximum yield of poly-mer product is less than 50%. In contrast, calcium 3-buteneoate that has a structurewith a network of parallel contacts �CDC� � � ��CDC� with distances 3.73 and3.90 A forms poly(3-buteneoate) with NMw D 400; 000 and 97% yield upon 60Co”-irradiation with 305 kGy dose. Metal trans-2-penteneoates display a wide range ofreaction ability in solid phase transformations. Some of them (MD Li, Mg, Zn, Cd,Pb) are unable to polymerize upon ”-irradiation, while others form dimers (MD K)or mixtures of oligomers (M D Na, Ca, Sr, Ba) [94]. Metal trans-2-penteneoatesundergo solid phase oxidation reaction leading to formation of metal acetylacrylateupon irradiation in air:

CO2 CO2M

n

O

Mn

γ-rays (5.16)

Apparently, there are no principal limitations for the solid state topochemicalreaction of Cd(II) itaconate, the structure of which was found to contain contactsbetween CDC� bonds with distances less than 4.2 A [95].

5.4 Copolymerization and Terpolymerization

Copolymerization with traditional monomers is widely employed for obtainingof metallopolymers based on metal carboxylates. This method allows involvingin polymerization processes even those carboxylates, which are incapable of ho-mopolymerization, but copolymerize readily with other monomers. There is anotherimportant aspect: since composition of the formed copolymer depends on a varietyof causes, copolymerization provides additional possibilities for investigation of fac-tors that affect reactivity of the multiple bond in the metal carboxylate molecule.Like in the case of classical copolymerization, composition of formed metallo-copolymers depends on the composition of the initial monomer mixture as well asrelative activities of the monomers and their radicals, consistent with Mayo-Lewisequation [96]:

Œm1�

Œm2�D ŒM1�

ŒM2�

r1ŒM1�C ŒM2�

ŒM1�C r2ŒM2�; (5.17)

where r2 D k22=k21 is copolymerization constant which describes the relative ac-tivity of metal carboxylate monomer in addition to the “own” and “strange” radicals,m2 and M2 is the content of metal carboxylate in the copolymer and monomermixture, respectively, and r1 D k11=k12, m1, and M1 are similar characteristics ofthe “metal-free” analog.

5.4 Copolymerization and Terpolymerization 129

It is known that the ability for polymerization enhances with increasing differ-ence in the resonance stabilization between the adding monomer and the radicalformed. In the Q–e scheme, Q is the characteristic of resonance stabilization of amonomer during copolymerization and e is the factor reflecting the magnitude of thepolarity effect of a substituent at the multiple bond. These parameters are associatedwith the relative reactivity constants by the following empirical equations:

r1 D .Q1=Q2/ expŒ�e1.e1 � e2/�I r2 D .Q2=Q1/ expŒ�e2.e2 � e1/� (5.18)

Copolymerization constants are found by the Mayo-Lewis method [96], with theapplication of various linearization techniques (such as Fineman–Ross [97], Kelen–Tudos [98] and others). Most commonly used is the Fineman-Ross linear form ofcopolymerization equation,

�F.1 � f / D r2 � r1F 2f; (5.19)

here F D ŒM1]/[M2] and f D Œm1]/[m2], which allows for quite simple graphicaldetermination of r1 and r2?

5.4.1 The Main Principles of Copolymerization of Alkaliand Alkaline Earth Metal Salts

The majority of studies point out a significant effect of the reaction medium, pri-marily ionic strength and solvent polarity, on the kinetic and copolymerizationparameters as well as properties of copolymers obtained, such as composition andmolecular mass. Change in the nature of interactions in the systems macroradical–counter ion–monomer anion with variation of composition of the medium is sug-gested to play the key role. In particular, it was shown for copolymerization ofacrylic acid salts with acrylamide [99] that at pH D 7.1–7.2, when the salts aredissociated, the rate of copolymerization diminishes with decreasing degree ofmetal ion binding by the polyacrylamide moiety of the macroradical. The degreeof cation binding with acrylate groups depends on the cation size and diminishesin the raw LiC > NaC > KC. Kinetic characteristics of MMA and alkali metalmethacrylates copolymerization in methanol were explained by electrostatic repul-sion between the salt functional groups and MMA radical [100]. The constants ofrelative reactivity for monomers (Table 5.6) indicate that a radical with terminalmetal methacrylate unit prefers binding with MMA monomer rather than with itsown one. This ability, defined as 1/r2, decreases with increasing ionic radius of al-kali metal cation (Fig. 5.15). This tendency may be correlated with the order ofvariation of homopolymerization rates for these salts, assuming that k22 increases,while k21 remains practically unchanged.

Such a behavior is also typical for other salts of this kind, and normally, thecopolymers formed are enriched in M1.r1 > 1; r2 < 1/ over the whole range of


Tab

le5.

6T

hepa

ram

eter

sof

copo

lym

eriz

atio

nof

alka

line

and

eart

h-al

kali

nem

etal

unsa

tura

ted

carb

oxyl

ates

Com

onom

ers

Cop

olym

eriz

atio

nco

nditi

ons

M1

M2

r 1r 2

Q2

e 2R

ef.

Met

hylm

etha

cryl

ate

Li(

OO

CC

(CH

3)D

CH

2/

Met

hano

l,A

IBN

0.01

%,6

0ı

C0.

590.

073

0:6

40:3

[100

]

Styr

ene

DM

SO,A

IBN

,0,

5%,6

0ıC

1.30

0.72

0:6

2�0

:54

[101

]

Li(

OO

CC

HDC

H2/

DM

SO,A

IBN

,0,

5%,6

0ıC

7.29

0.07

0:0

70:0

2[1

01]

Met

hylm

etha

cryl

ate

Na(

OO

CC

(CH

3)D

CH

2/

Met

hano

l,A

IBN

0.01

%,6

0ı

C3.

970.

126

1:3

6�0

:18

[100

]

K(O

OC

C(C

H3)D

CH

2/

Met

hano

l,A

IBN

0.01

%,6

0ı

C5.

650.

173

0:5

40:0

1[1

00]

Styr

ene

Mg(

OO

CC

HDC

H2/ 2

DM

SO,A

IBN

0.5%

,70

ıC

5.31

˙0.

070.

18˙

0.14

0:1

6�0

:59

[102

]

Ca(

OO

CC

HDC

H2/ 2

DM

SO,A

IBN

0.5%

,70

ıC

6.10

˙0.

220.

12˙

0.02

0:1

1�0

:24

[102

]

Sr(O

OC

CH

DCH

2/ 2

DM

SO,A

IBN

0.5%

,70

ıC

4.12

˙0.

020.

14˙

0.05

0:1

3�0

:06

[102

]

Ba(

OO

CC

HDC

H2/ 2

DM

SO,A

IBN

0.5%

,70

ıC

3.95

˙0.

150.

11˙

0.02

0:1

20:1

1[1

02]


14

12

10

8

00.6 0.8

Li

Na

K

1.0Ion radius / Å

1.2

1/r2

Fig. 5.15 Ratio 1=r2 vs. cation radius in the copolymerization of MMA with alkali metalmethacrylates

monomer mixture compositions (Table 5.6). Only in the case of lithium salts, insuch systems as Li methacrylate-MMA [100] and Li acrylate-styrene [101], the ex-pressed tendency for a regular alternation of monomer units is observed. At thesame time, the product of multiplication of copolymerization constants for the pairstyrene-Li methacrylate .r1; r2 D 0:94/ is close to 1, which is indicative of nearlyideal copolymerization. Differences in reactivity of acrylate and methacrylate lig-ands are reflected in the parameters Q and e. Thus, the value of Q is 0.64 and 0.07for Li methacrylate and Li acrylate monomers, respectively, which is in agreementwith general tendency of 1,1-disubstituted ethylenes for having larger Q values thanthe monosubstituted ones. Substitution of a hydrogen atom with a CH3 group inmethacrylate causes change both in the magnitude and the sign of the double bondpolarity (eLi acrylate D C0:02 and eLi methacrylate D �0:54). The negative value of e

indicates an elevated electron density on the vinyl group due to electron donatingnature of methyl group. Polarity effects influence noticeably copolymerization ofMg, Ca, Sr, and Ba acrylates with styrene in DMSO [102]. For the monomers stud-ied, the magnitude of e increases in the order: Mg < Ca < Sr < Ba. Escalation of theunit alternation, i.e., gradual decrease of the product r1, r2 follows the same order.

5.4.2 Reactivity of Tin-Containing Carboxylates

The key features of copolymerization of trialkyltin (meth)acrylates and maleateswith vinyl monomers [103–105] are that the comonomers are randomly distributed


Table 5.7 The parameters of copolymerization of Sn-containing unsaturated carboxylates

Comonomers

M1 M2 r1 r2 Q2 E2 Ref.

MMA (n-Bu)3

Sn(OOCCHDCHCOOH)

15.40 ˙ 0.98 0.01 ˙ 0.02 0:05 1:40 [103]

Styrene 6.70 ˙ 0.39 0.05 ˙ 0.10 [103]

Butylacrylate 9.39 ˙ 0.21 0.11 ˙ 0.08 [103]

Acrylamide 122.44 ˙ 6.04 0.06 ˙ 0.20 [103]

Acrylamide (n-Bu)3

Sn(OOCCHDCH2/

0.11 ˙ 0.02 0.82 ˙ 0.06 0:38 0:74 [103]

Itaconic acid 0.011 ˙ 0.109 1.088 ˙ 0.044 0:313 0:774 [105]

Dimethylitaconate 0.767 ˙ 0.181 0.932 ˙ 0.040 [105]

Acrylamide (n-Bu)3

Sn(OOCC(CH3)DCH2/

1.460 ˙ 0.40 0.85 ˙ 0.10 0:62 0:57 [103]

Itaconic acid 0.073 ˙ 0.090 2.272 ˙ 0.080 0:575 1:300 [105]

Dimethylitaconate 0.829 ˙ 0.101 1.223 ˙ 0.036 [105]

Styrene (n-Bu)3

Sn(OOCCH2

C(COOSn(n-Bu)3/]DCH2/

0.643 ˙ 0.039 0.139 ˙ 0.058 [106]

MMA 1.729 ˙ 0.129 0.316 ˙ 0.100 [106]

over the chain, the trend for alternation increasing with an increase in the lengthof the alkyl chain in the (meth)acrylate monomer. The type of variation of thecopolymerization parameters on going from acrylate to methacrylate (the r1, r2

value increases from 0.09 to 1.24) for copolymerization of AAm with tributyltin(meth)acrylate derivatives [103] (Table 5.7) is similar to that discussed previouslyfor lithium salts. For tributyltin maleate, the copolymers are enriched with thecomonomer units, also the effective constants are abnormally high, especiallyfor acrylamide .r1D122:44; r2D0:06/. Hence, tributyltin maleate copolymerswith styrene, MMA, butyl acrylate or AAm are composed of large blocks of thecomonomer separated by single maleate units. Moreover, in all cases, the r2 value isclose to zero (see Table 5.7), which indicates the inability of the maleate monomerto homopolymerization. Good agreement was found between the theoretically cal-culated and experimental values of triads in the chain sequences of di(tributyltin)itaconate and MMA copolymer [106] (Table 5.8). This fact confirms the preferredaddition of methyl methacrylate units to the growing macroradical and, hence, theformation of longer polymer chains from them.


Table 5.8 Theorethical and experimental triad distributions in copolymers ofdi(tributyltin)itaconates .M2/ and MMA .M1/ [106]

f111 C f112 f212

f1 Experimental Theorethical Experimental Theoretical

0:50 0:8333 0:8636 0:1667 0:1364

0:55 0:8750 0:8861 0:1250 0:1140

0:65 0:9280 0:9411 0:0720 0:0589

0:75 0:9688 0:9713 0:0312 0:0287

0:90 1:0000 0:9951 0:0000 0:0040

The remote position of a tin carboxylate center in respect to double bond inmolecules of tributyltin 4-(p-styryl)-butaneoate [107] and tributyltin 4-(p-styryl)-propaneoate [108] ensures relatively high yields of polymeric products and thereaction rates.

O

OSnBu3

x +

O

OSnBu3

1-x

x 1-x

AIBN

x=0.2-1

5.4.3 Copolymerization of Transition Metal Salts

Since metal di(meth)acrylates and dicarboxylates are nonconjugated divinylmonomers, the equation of copolymerization in these systems has the form:

Œm1�

Œm2�D ŒM1�

2ŒM2�

r1ŒM1�C ŒM2�

ŒM1�C 2r2ŒM2�; (5.20)

It is assumed that intramolecular cyclization or intermolecular ion cross-linking canbe neglected, at least, at low degrees of conversion:

(5.21)~M·

1 + C

Mn+

C C

CC M1

CC

Mn+

Mn+

C M.1

C

~M1

~M1

C

.C C (5.22)


It was shown by special studies [109, 110] that the products formed in initialcopolymerization stages are soluble in organic solvents; therefore, no intermolec-ular cross-linking by acrylate groups takes place. The number of the non-consumeddouble bonds in metal acrylates increases in the series Zn2C (35%) < Co2C (39%)< Ni2C (49%).

Despite the general rule on relatively lower activity of the analyzed carboxylates,compared to traditional monomers, as observed in homopolymerization reactions,copolymers on their base can differ significantly by microstructure of polymerchains, depending on the nature of the comonomer and the reaction medium as awhole. Copolymers based on carboxylic acid salts may differ considerably in the mi-crostructure of polymeric chains, which depends on the comonomer nature and thereaction medium. In the copolymerization of transition metal acrylates with styrenein methanol, it was found that r1 > 1 and r2 < 1 (Table 5.9) [111]. It is obvious, thatwith these copolymerization constants, the resulting copolymer will be enriched instyrene irrespective of the composition of the reaction mixture. Conversely, whenthe reaction is carried out in DMF, alternation of the monomer units is observed inthe polymer formed from the same monomer pairs. In the nickel acrylate–styrenecopolymer, 46% of the acrylate units are incorporated in regularly alternating struc-tures [110]. This behavior may be due to the change in the double bond polarityand, hence, parameters of the reactivity of acrylates in polar solvents, as is the case,for example, of styrene copolymerization with acrylamide in DMSO [112]. How-ever, in the case of copolymerization of copper acrylate with styrene in methanolor acetonitrile the copolymerization parameters are not changed much [111]. Theeffective values of relative activity of the monomers (Table 5.9) attest to a statisti-cal structure of the copolymer of MMA with chromium [113], copper [114, 115],and nickel [116] acrylates obtained by bulk polymerization. In the metal acrylate–acrylonitrile system, the opposite signs of double bond polarity (parameters e andQ for acrylonitrile are 1.2 and 0.6, respectively) account for S-shaped compositioncurves according to the classical copolymerization theory and for the clear-cut trendfor alternation of copolymer units in the product [117–119] (Fig. 5.16). The trendfor comonomer alternation is also found in the copper maleate–styrene copolymer:the product r1; �r2 < 1, and the regularly alternating structures account for morethan 50% of elementary units) [120]. However, in the cobalt hydrogen maleate–styrene system, the trend for alternation is slight, as the styrene concentration in themonomer mixture increases, long .n > 10/ polystyrene chains separated by maleateunits are formed in the copolymer.

5.4.4 Kinetic Features

The rate of radical copolymerization of styrene or acrylonitrile with zinc, cobalt,and nickel acrylates increases with an increase in the salt content in the monomermixture [109–111]. This is especially pronounced in the case of zinc acrylate


Tab

le5.

9T

hepa

ram

eter

sof

copo

lym

eriz

atio

nof

tran

sitio

nm

etal

unsa

tura

ted

carb

oxyl

ates

Com

onom

ers

Cop

olym

eriz

atio

nco

nditi

ons

M1

M2

r 1r 2

Q2

e 2R

ef.

Zn(

OO

CC

HDC

H2/ 2

Met

hano

l,A

IBN

0.5%

1.10

˙0.

020.

90˙

0.07

0.84

�0:7

0[1

11]

Acr

ylon

itri

leZ

n(O

OC

CH

DCH

2/ 2

DM

F,A

IBN

9�1

0�

3m

ol/L

,60

ıC

0.41

˙0.

020.

24˙

0.03

0.24

�0:3

0[1

18]

Styr

ene

Co(

OO

CC

HDC

H2/ 2

Met

hano

l,A

IBN

0.5%

1.74

˙0.

030.

56˙

0.09

0.51

�0:6

4[1

11]

Acr

ylon

itri

leD

MF,

AIB

N9

�10

�3

mol

/L,

60

ıC

0.14

˙0.

020.

15˙

0.01

0.42

�0:7

5[1

17]

Styr

ene

Ni(

OO

CC

HDC

H2/ 2

Met

hano

l,A

IBN

0.5%

1.83

˙0.

020.

53˙

0.06

0.48

�0:6

3[1

11]

Acr

ylin

itri

leD

MF,

AIB

N9

�10

�3

mol

/L,

60

ıC

0.09

˙0.

020.

17˙

0.02

0.59

�0:8

5[1

17]

Styr

ene

Cu(

OO

CC

HDC

H2/ 2

Met

hano

l,A

IBN

2%,8

0ı

C6.

340.

11[1

11]

Styr

ene

Ace

toni

tril

e,A

IBN

2%,8

0ı

C5.

94˙

0.05

0.12

˙0.

080.

11�0

:22

[111

]

Acr

ylon

itri

leD

MF,

AIB

N9

�10

�3

mol

/L,

60

ıC

0.21

˙0.

010.

08˙

0.02

0.26

�0:8

2[1

17]

MM

AIn

bulk

,2:6

88

�10

�3

mol

/LB

P,60

ıC

1.05

0.8

[114

]

MM

AC

r(O

OC

CH

DCH

2/ 3

Inbu

lk,2

:688

�10

�3

mol

/LB

P,60

ıC

1.08

0.95

[113

]

Acr

ylon

itri

leD

MF,

As 2

S 3-s

tyre

ne,8

5ı

C0.

180.

03[1

19]

Styr

ene

Co(

HO

OC

CH

DCH

CO

O) 2

Eth

anol

,70

ıC

,0.0

1m

ol/L

AIB

N1.

45˙

0.00

10.

34˙

0.00

10.

350:0

4[1

20]

Styr

ene

Co(

OO

CC

HDC

HC

OO

)E

than

ol,7

0ı

C,0

.01

mol

/LA

IBN

0.45

˙0.

004

0.07

˙0.

004

0.50

1:0

4[1

20]


[m2]a b

c d

0.8

0.4

0 0.2 0.6 [M2]

[m2]

0.8

0.4

0 0.2 0.6 [M2]

[m2]

0.8

0.4

0 0.2 0.6 [M2]

[m2]

0.8

0.4

0 0.2 0.6 [M2]

Fig. 5.16 Copolymerization diagrams of the systems acrylonitrile (M1/ – zinc(II) (a), cobalt(II)(b), nickel(II) (c) and copper(II) (d) acrylates

(Fig. 5.17), because the highest electron delocalization is expected due to the lowestelectronegativity of zinc ion in this series of metals. Copper acrylate sharply inhibitsthe process, probably, by a mechanism similar to the mechanism of its homopoly-merization.

When dicarboxylic acid salts are used, for example, in pair cobalt hydrogenmaleate–styrene, the rate of copolymerization decreases monotonically with an in-crease of the dicarboxylate monomer fraction in the initial mixture. However, inthe case of neutral cobalt maleate–styrene system, this dependence passes througha maximum at the equimolar reactant ratio (Fig. 5.18) [120].

This type of behavior is often attributed to the donor-acceptor interactionsbetween the comonomers, as in the copolymerization of sodium 2-acrylamido-2-propanesulfonate with N -vinylpyrrolidone in water and DMSO [121].


Fig. 5.17 Yield of theproduct of styrenecopolymerization with metalacrylates vs. time. Content ofzinc acrylate in thecomonomer mixture: 2 (1),6 (2), 10 wt% (3); content ofcopper acrylate: 2 (4), 6 wt%(5) for Cu2C; Forcomparison, the curve forstyrene homopolymerizationis given

15 3

2

1

6

54

P (%)

12

9

6

3

0 2 4 6 8 time, h

1.4

Wo / cal mol–1 s–1

1.2

1.0

0.8

0.2 0.3 0.4 0.5 0.6[M2] / mole fraction

Fig. 5.18 Initial rate of styrene copolymerization with Co(cis-HOOCCHDCHCOO)2 (1) andCo(cis-OOCCHDCHCOO) (2) vs. carboxylate content

Mathematical simulation of the experiment gave equations that describe adequatelythe dependence of the rate of copolymerization of Zn2C, Co2C, Ni2C, and Cu2Cacrylates with acrylonitrile (AN) [122, 123]:

Wp D K.ŒM1�C ŒM2�/n1 ŒI�n2 ; (5.23)

Wp D A0.ŒM1�C ŒM2�/n1 ŒI�n2 exp.�Ea=RT/; (5.24)


Table 5.10 The copolymerization kinetic parameters of transition metal acrylates with acrylo-nitrile

Metal

Parameter Zn2C [122] Co2C [123] Ni2C [123] Cu2C [122] Cr3C [119]

A0, L0:5

mol�0:5 s�0:5

(4.67 ˙ 0.06)107 (4.4 ˙ 0.3)1010 (3.3 ˙ 0.3)109 (6.8 ˙ 1.1)109

n1 1.67 ˙ 0.10 1.59 ˙ 0.10 1.65˙0.05 1.12 ˙ 0.10 1n2 0.61 ˙ 0.07 0.57 ˙ 0.14 0.55 ˙ 0.07 0.78 ˙ 0.07 0.5Ea, kJ mol�1 72.5 ˙ 4.9 92.6 ˙ 6.8 86.0 ˙ 3.6 88.2 ˙ 5.0 96.2 ˙ 0.2k2

p/kt, Lmol�1 s�1

1:0 � 10�5

K348, L0:5

mol�0:5 s�0:5

6.16 � 10�4 5.55 � 10�4 4.15 � 10�4 3.98 ˙ 10�4

where [M1] and [M2] are concentrations of the precursor monomers, [I] is concen-tration of the initiator, mol/L, n1 and n2 are the orders of reaction with respect tothe total concentration of monomers and the initiator, respectively, K is the overallreaction rate constant, A0 is the preexponential factor, Ea is the overall activationenergy.

The kinetic parameters of copolymerization for the monomer pairs consideredsuggest a complicated influence of the nature of a metal on the elementary steps ofthe polymerization process (Table 5.10). As in the homopolymerization, the generaltrend of variation of the reaction rate constant in the series Zn2C > Co2C > Ni2C >

Cu2C is retained. However, copolymerization of Cr(III) acrylate with acrylonitrilefollows the ideal radical polymerization kinetics (see Table 5.10) [119].

It is noteworthy that when a great excess of AN is present in the system AN–zincacrylate, the rate constant .2kdf .1:6˙ 0:26/� 10�5 s�1) and the activation energy(126:8 ˙ 3:7 kJ mol�1) for initiation of the copolymerization do not differ muchfrom those found for the homopolymerization of AN [124].

5.4.5 Terpolymerization

Terpolymerization is important for practical purposes as it provides even morepossibilities of varying the properties of the final product. In most cases, two ter-monomers are present in the terpolymer in greater amounts and are responsible forits key properties, while the third one is added only for modification of the requiredproperty of the polymeric material. From this point, the use of salts of unsaturatedacids as the third monomer allows control of the reactivity of vinyl monomers, anddetermination of the spatial configuration and morphology of the products. Indeed,even minor additives (0.5–2.0 mol%) of alkali and alkaline earth metal methacry-lates introduced in the MMA–MAA system (90:10) in bulk copolymerization havea noticeable effect on the parameters r1 and r2 and the radical copolymerization


kinetics, thus determining the physicochemical properties of the copolymers havingthe following structure [41, 125, 126]:

CH2 CH2 CH2C

CH3 CH3 CH3

CO

OCH3

C

CO

OH OM

OC

Cn pm

The introduction of metal methacrylate increases the yield and molecular mass ofcopolymerization products. These unusual facts were explained by inclusion of thesalt into complexation with the system components. This affects the intermolecularinteractions, giving rise to specific areas (intermediates) with a definite orientationof the monomer molecules. As a result, the reaction is accelerated and more regularand longer macrochains are formed (i.e., similar phenomena, that accelerate thepolymerization of complexed monomers [127]) (Fig. 5.19).

In addition, in the presence of a salt, the product r1, r2 decreases, which cor-responds to an increase in the degree of alternation of monomer units, as is alsoindicated by the change in the Harwoord parameter (Table 5.11).

The formation of terpolymers, for example, in the systems tributyltinmethacrylate–butyl methacrylate–acrylonitrile [128], di(tributyltin) itaconate(TBOI)–methyl (MA) or ethyl acrylate (EA)–acrylonitrile (AN) [129], followscopolymerization kinetics constants for binary systems of monomer pairs. This factwas also noted for terpolymerization of zinc [130], chromium [131], and copper[132] acrylates with styrene and acrylonitrile. Ternary azeotropic compositions, forexample, for the systems TBOI–MA–AN and TBOI–MA–EA are equal to 37:48:15and 9:80:11 mol%, respectively [129], and are in good agreement with the theoret-ically calculated values (Fig. 5.20), that is the terpolymerization in such systemsobeys the ideal copolymerization laws.

The kinetic parameters of terpolymerization for the monomers under consider-ation are also in agreement with the classical views on the effects of initiator andmonomer concentrations on the reaction rate. Thus, for example, terpolymerization

Fig. 5.19 Copolymerizationconversion vs. time for thesystem of MMA and MAA inthe presence of 1% metalmethacrylate: (1) Bi, (2) Ba,(3) Na, (4) without salts

P, %

80

1 2 3 4

60

40

20

0 30 60 90 time, min


Table 5.11 The change of the copolymerization constants of MMA (M1/ and MAA(M2/ at intro-ducing metal methacrylate into copolymerization system [126]

The system r1 r2 r1, r2 The Harwoord parameter

MMA–MAA 0.37 ˙ 0.06 0.85 ˙ 0.03 0:315 36.90MMA–MAA–

LiMAA0.12 ˙ 0.02 0.16 ˙ 0.02 0:019 66.45

MMA–MAA–NaMAA

0.19 ˙ 0.03 0.11 ˙ 0.03 0:021 53.76

MMA–MAA–KMAA

0.27 ˙ 0.02 0.08 ˙ 0.04 0:022 45.05

MMA–MAA–CuMAA

0.36 ˙ 0.02 0.34 ˙ 0.02 0:122 41.7

MMA–MAA–CoMAA

0.59 ˙ 0.01 0 0 30.7

20100

80

60

40

20

0100

80

60

40MA

20

0

AN

40 60

TBTI

80 1000

Fig. 5.20 Composition of the bis(tributyltin) itaconate–methyl acrylate–acrylonitrile terpolymervs. composition of the initial mixture. The ends of arrows point to the molar composition of thecopolymer obtained from monomer mixtures with contents corresponding to the coordinates ofpoints in the arrow; the azeotrope boundary is shown by the dashed line

of copper acrylate, styrene, and acrylonitrile is described by the equation:W D ŒI�0:5[St][AN] (1/[CuAA]) (where I stands for p-acetylbenzylidenetripheny-larsenic ylide), while constants of the relative reactivity, r1.St/ D 5˙ 2 andr2(ANC CuAA)D 0.4˙ 0.02, point to a random distribution of monomer units inthe polymer chain [132]. Like in numerous cases mentioned above, and assumingly,by the analogous mechanism, an increase in copper acrylate concentration resultsin the decreased polymerization rate (Table 5.12).

References 141

Table 5.12 The influence of the concentration of copper (II) acrylate onthe rate of terpolymerization [132]

[CuAA] (mol/L) Conversion (%) Wp � 105 (mol/L s)

0.062 12.3 –0.093 10.3 2.10.124 7.9 1.70.155 6.6 1.3

At the same time, for copper methacrylate copolymerization with hydroxyethylmethacrylate in the presence of 1,1,1-tris(hydroxymethyl)propanetrimethacrylate,the terpolymer yield was quite high (70–80%) and essentially invariant with saltconcentration changing from 2.7 to 3.82 mol% [133].

Therefore, homo- and copolymerization of unsaturated metal carboxylates areextensively studied areas of polymer science. On one hand, this is one of the mostimportant methods for obtaining of metallopolymers. On the other hand, the pres-ence of metal in a comonomer provides additional opportunities for the study of thefinest mechanisms of copolymerization processes. In addition, a huge amount of in-formation has been accumulated which still needs to be systematized. This requiresdevelopment of the theory of copolymerization kinetics, in particular, a revision ofthe Q� e scheme, as well as detailed account for accompanying complexation, re-dox, and other processes. Copolymerization of comonomers with different metalsneeds to be developed. Intense development of this area of science allows for solv-ing of these problems in the nearest future.

References

1. Pat. 59–64615 Japan (1984)2. N.Yu. Novospaskaya, A.N. Smeleva, Physico-Chemical Processes of Synthesis and Proper-

ties of Polymers (Gorkii University, Gorkii, 1988), p. 293. B. Chaturvedi, A.K. Srivastava, Indian J. Technol. 3, 854 (1993)4. B.S. Selenova, G.I. Dzhardimalieva, M.V. Tsykalova, S.V. Kurmaz, V.P. Roshchupkin,

I.Ya. Levitin, A.D. Pomogailo, M.E. Vol’pin, Izv. Akad. Nauk SSSR, Ser. Khim. 500 (1993)5. I.Ya. Levitin, M.E. Vol’pin, J. Mol. Catal. 23, 315(1984)6. B.S. Selenova, G.I. Dzhardimalieva, E..B. Baishiganov, O.N. Efimov, A.D. Pomogailo, Izv.

Akad. Nauk SSSR, Ser. Khim. 1025 (1989)7. S.M. Schlitter, H.P. Beck, Chem. Ber., 129, 1561 (1996)8. M.J. Vela, B.B. Snider, B.M. Foxman, Chem. Mater. 10, 3167 (1998)9. A. Galvan-Sanchez, F. Urena-Nunez, H. Flores-Llamas, R. Lorez-Castanares, J. Appl. Polym.

Sci. 74, 995 (1999)10. J.H. O’Donnell, P.J. Pomery, R.D. Sothman, Macromol. Chem. 181, 409 (1980)11. M.R. Muidiniv, G.I. Dzhardimalieva, B.S. Selenova, A.D. Pomogailo, Izv. Akad. Nauk SSSR,

Ser. Khim. 2507 (1988)12. P.-Y. Jiang, Z.-C. Zhang, M.-W. Zhang, J. Polym. Sci. A Polym. Chem. 34, 695 (1996)13. A. Gbureck, U. Gbureck, W. Kiefer, U. Posset, R. Thull, Appl. Spectrosc. 54, 390 (2000)14. U. Gbureck, J. Probst, R. Thull, J. Sol–Gel Sci. Technol. 27, 157 (2003)15. J.P. Rabe, J.F. Rabolt, C.A. Brown, J.D. Swalen, J. Chem. Phys. 84, 4096 (1986)


16. L. Marcot, P. Maldivi, J.-C. Marchon, D. Guillon, M. Ibn-Elhaj, Chem. Mater. 9, 2051 (1997)17. D. Greszta, K. Matyjaszewski, Macromolecules 29, 7661 (1996)18. K. Matyjaszewski, Y. Nakagawa, C.B. Jasieczek, Macromolecules 31, 1535 (1998)19. T.E. Patten, K. Matyjaszewski, Adv. Mater. 10, 91 (1998)20. E.J. Ashford, V. Naldi, R. O’Dell, N.C. Billingham, S.P. Armes, Chem. Commun. 1285 (1999)21. V.L. Osborne, D.M. Jones, W.T.S. Huck, Chem. Commun. 1838 (2002)22. S. Tugulu, R. Barbey, M. Harms, M. Fricke, D. Volkmer, A. Rossi, H.-A. Klok, Macro-

molecules 40, 168 (2007)23. A. Yoshiro, M. Shuichi, M. Takeshi, S. Kaname, Yukagoku 31, 586 (1982)24. A.D. Pomogailo, V.S. Savost’yanov, Metal-Containing Monomers and Their Polymers

(Khimiya, Moscow, 1988)25. V.A. Kabanov, D.A. Topchiev, Polymerization of Ionizing Monomers (Nauka, Moscow, 1975)26. R.P. Hopkins, Ind. Eng. Chem. 47, 2258 (1955)27. T. Czerniawski, Eur. Polym. J. 36, 635 (2000)28. T. Czerniawski, H. Dynasinska, Z. Wojtczak, Polimery 28, 78 (1983)29. T.F. Loginova, A.A. Shubin, V.V. Vyalkov, V.N. Kisel’nikov, Izv. Vyssh. Ucheb. Zaved.

Khim. Khim. Tekhnol. 26, 1476 (1983)30. P.-Y. Jiang, Z.-C. Zhang, M.-W. Zhang, J. Polym. Sci. A Polym. Chem. 34, 695 (1996)31. L.-Y. Liu, Z.-X. Zhang, W.-T. Yang, Chinese J. Polym. Sci. 23, 219 (2005)32. Z. Woitczak, A. Gronowskii, Polimery 27, 471 (1982)33. T. Czerniawski, Z. Wojtczak, Acta Polymerica 40, 442 (1989)34. Z. Wojtczak, T. Czerniawski, Acta Polymerica 40, 409 (1989)35. T. Czerniawski, Z. Wojtczak, Eur. Polym. J. 32, 1035 (1996)36. G.I. Dzhardimalieva, A.D. Pomogailo, S.P. Davtyan, V.I. Ponomarev, Izv. Akad. Nauk SSSR,

Ser. Khim. 1531 (1988)37. G.I. Dzhardimalieva, A.D. Pomogailo, Macromol. Symp. 131, 19 (1998)38. M.V. Klyuev, L.V. Tereshko, A.D. Pomogailo, Izv. Akad. Nauk SSSR, Ser. Khim. 2531 (1986)39. Yu.M. Shulga, O.S. Roshchupkina, G.I. Dzhardimalieva, A.D. Pomogailo, Izv. Akad. Nauk

SSSR, Ser. Khim. 1565 (1993)40. G. Schroeder, Macromol. Chem. 97, 232 (1966)41. V.N. Serova, O.P. Shmakova, V.V. Chirkov, V.I. Morozov, V.P. Arkhireev, Vysokomol. Soedi-

nen. A 41, 970 (1999)42. M. Zeldin, J.J. Kin, J. Polym. Sci. Polym. Chem. Ed. 23, 2333 (1985)43. V.P. Roshchupkin, B.V. Ozerkovskii, Z.A. Karapetyan, Vysokomol. Soedinen. A 19, 2239

(1977)44. I.A. Chernov, G.F. Novikov, G.I. Dzhardimalieva, A.D. Pomogailo, Vysokomol. Soedinen. A

49, 428 (2007)45. M.J. Vela, V. Buchholz, V. Enkelmann, B.B. Snider, B.M. Foxman, Chem. Commun.

2225 (2000)46. G.C.D. Delgado, K.A. Wheeler, B.B. Snider, B.M. Foxman, Angew. Chem. Int. Ed. Engl. 30,

420 (1991)47. T.H. Cho, B. Chaudhuri, B.B. Snider, B.M. Foxman, J. Chem. Soc. Chem. Commun.

1337 (1996)48. A. Galvan-Sanchez, F. Urena-Nunez, H. Flores-Llamas, R. Lorez-Castanares, J. Appl. Polym.

Sci. 74, 995 (1999)49. G.V. Korolev, E.O. Perepelitsina, Vysokomol. Soedinen. A 43, 774 (2006)50. G.V. Korolev, E.O. Perepelitsina, Dokl. Akad. Nauk. 371, 488 (2000)51. V. Korolev, A.A. Ilin, M.M. Mogilevich, V.P. Grachev, E.O. Perepelitsina, E.S. Evplonova,

Vysokomol. Soedinen. A 45, 883 (2003)52. Al. Berlin, G.M. Trofimova, L.K. Pachomova, J. Polym. Sci. C 16, 2323 (1967)53. C.F. Parrish, G.L. Kochanny, Macromol. Chem. 115, 119 (1968)54. C.H.L. Kennard, G. Smith, T.M. Greaney, A.H. White, J. Chem. Soc. Perkin Trans. 302 (1976)55. M.J. Bowden, J.H. O’Donnel, J. Macromol. Sci. Chem. A 12, 63 (1978)56. K. Naruchi, S. Janaka, M. Higuma, et al., Polymer 23, 152 (1982)57. A. Gronowski, Z. Wojtczak, J. Therm. Anal. 26, 233 (1983)

References 143

58. E.I. Aleksandrova, G.I. Dzhardimalieva, A.S. Rozenberg, A.D. Pomogailo, Izv. Akad. NaukSSSR, Ser. Khim. 303 (1993)

59. A.S. Rozenberg, G.I. Dzhardimalieva, A.D. Pomogailo, Dokl. Akad. Nauk. 356, 66 (1997)60. A.S. Rozenberg, G.I. Dzhardimalieva, A.D. Pomogailo, Polym. Adv. Technol. 9, 527 (1998)61. E.I. Aleksandrova, G.I. Dzhardimalieva, A.S. Rozenberg, A.D. Pomogailo, Izv. Akad. Nauk

SSSR, Ser. Khim. 308 (1993)62. A.S. Rozenberg, E.I. Aleksandrova, A.N. Titkov, G.I. Dzhardimalieva, A.D. Pomogailo, Izv.

Akad. Nauk SSSR, Ser. Khim. 1743 (1993)63. A.S. Rozenberg, G.I. Dzhardimalieva, N.V. Chukanov A.D. Pomogailo, Kolloidn. Zh. 67,

57 (2005)64. A.S. Rozenberg, E.I. Aleksandrova, N.P. Ivleva, G.I. Dzhardimalieva, A.V. Raevskii,

O.I. Kolesova, I.E. Uflyand, A.D. Pomogailo, Izv. Akad. Nauk SSSR, Ser. Khim. 265 (1998)65. A.T. Shuvaev, A.S. Rozenberg, G.I. Dzhardimalieva, N.P. Ivleva, V.G. Vlasenko,

T.I. Nedoseikina, T.A. Lubeznova, I.E. Uflyand, A.D. Pomogailo, Izv. Akad. Nauk SSSR,Ser. Khim. 1505 (1998)

66. H.-J. Glasel, E. Hartmann, D. Hirsch, R. Bottcher, C. Klimm, D. Michel, H.-C. Semmelhack,J. Hormes, H. Rumpf, J. Mater. Sci. 34, 2319 (1999)

67. B.M. Baysal, H.M. Erten, U.S. Ramelov, J. Polym. Sci. A-1 9, 581 (1971)68. A.V. Ryabov, Yu. D. Semchikov, L.A. Smirnova, Vysokomol. Soedin. A 13, 1414 (1971)69. H. Morawetz, I.D. Rubin, J. Polym. Sci. 57(Pt 2), 669 (1962)70. P.P. Saviotti, D.F.R. Gilson, J. Phys. Chem. 80, 1057 (1976)71. F.B. Watine, L.E. St-Pierre, J. Polym. Sci. Polym. Symp. 123 (1973)72. F.M. Costaschuk, D.F.R. Gilson, L.E. St-Pierre, J. Phys. Chem. 74, 2035 (1970)73. M.J. Bowden, J.H. O’Donnel, Macromolecules 1, 499 (1968)74. J.H. O’Donnel, R.D. Sothman, Radiat. Phys. Chem. 13, 77 (1979)75. M.J. Bowden, J.H. O’Donnel, R.D. Sothman, Macromolecules 5, 268 (1972)76. X. O’Donnel, P.J. Pomery, R.D. Sothman, Macromol. Chem. 181, 409 (1980)77. A.R. Vilchis-Nestor, V. Sanchez-Mendieta, F. Urena-Nunez, R. Lopez-Castanares,

J.A. Ascencio, J. Appl. Polym. Sci. 102, 5212 (2006)78. K.C. Tripathi, P.R. Sarma, H.M. Gupta, J. Polym. Sci. Polym. Lett. 16, 629 (1978)79. P.R. Sarma, K.C. Tripathi, H.M. Gupta, J. Polym. Sci. Chem. Ed. 18, 2609 (1980)80. M.D. Cohen, G.M.J. Schmidt, J. Chem. Soc. 1996 (1964)81. G. Wegner, Pure Appl. Chem. 49, 443 (1977)82. S.K. Kearley, in Organic Solid State Chemistry, ed. by G.R Desiraju (Elsevier. Amsterdam,

1987), p. 69)83. R.F. Schlam, Thesis Dr.PhD (Brandeis University, UMI, Ann Arbor, 1998)84. D.J. Sandman, G.P. Hamill, L.A. Samuelson, B.M. Foxman, Mol. Cryst. Liq. Cryst. 106, 199

(1984)85. K.A. Wheeler, B.M. Foxman, Chem. Mater. 6, 1330 (1994)86. O.A. Ushakova, I.V. Isakov, E.E. Rider, G.N. Gerasimov, A.D. Abkin, Vysokomol. Soedin.

Ser. B. 20, 112 (1978)87. M.J. Moloney, B.M. Foxman, Inorg. Chim. Acta. 229, 323 (1995)88. J.S. Brodkin, B.M. Foxman, J. Chem. Soc. Chem. Commun. 1073 (1991)89. C.B. Case, B.M. Foxman, Inorg. Chim. Acta. 222, 339 (1994)90. J.S. Brodkin, B.M. Foxman, Chem. Mater. 8, 242 (1996)91. S.M. Schlitter, H.P. Beck, Chem. Ber. 129, 1561 (1996)92. A. Matsumoto, T. Odani, M. Chikada, K. Sada, M. Miyata, J. Am. Chem. Soc. 119, 11122

(1999)93. A. Matsumoto, T. Odani, Chem. Lett. 33, 42 (2004)94. L. Di, B.M. Foxman, Chem. Mater. 4, 258 (1992)95. J.E. Contreras, B.V. Ramirez, X. Graciela Diaz de Delgado, J. Chem. Cryst. 27, 391 (1997)96. F.R. Mayo, F.M. Lewis, J. Am. Chem. Soc. 66, 1594 (1944)97. M. Fineman, S. Ross, J. Polym. Sci. 2, 259 (1950)98. T. Kelen, F. Tudos, J. Macromol. Sci. Chem. A 9, 1 (1975)99. K. Plochocka, T. Wojnarowski, Eur. Polym. J. 8, 921 (1972)


100. A. Hamoudi, I.C. McNeil, Eur. Polym. J. 14, 177 (1978)101. A. Gronowski, Z. Wojtczak, Eur. Polym. J. 25, 241 (1989)102. A. Gronowski, Z. Wojtczak, Macromol. Chem. 190, 2063 (1989)103. N.E. Ikladious, A.F. Shaaban, Polymer. 24, 1635 (1983)104. N.A. Ghamen, N.N. Messiha, N.E. Ikladious, A.F. Shaaban, Eur. Polym. J. 15, 823 (1979);

16, 339 (1980)105. A.F. Shaaban, M.A. Salem, M.M. Azab, N.N. Messiha, Acta Polymerica 39, 654 (1988)106. A.F. Shaaban, N.M.H. Arief, A.A. Mahmoud, J. Appl. Polym. Sci. 33, 1735 (1987)107. L. Angiolini, D. Caretti, E. Salatelli, L. Mazzocchetti, R. Willem, M. Biesemans, J. Inorg.

Organomet. Polym. 18, 236 (2008)108. L. Angiolini, M. Biesemans, D. Caretti, E. Salatelli, R. Willem, Polymer 41, 3913 (2000)109. A. Gronowski, Z. Wojtczak, Acta Polymerica 36, 59 (1985)110. G.I. Dzhardimalieva, A.D. Pomogailo, Izv. Akad. Nauk SSSR, Ser. Khim. 352 (1991)111. Z. Wojtczak, A. Gronowski, Macromol. Chem. 186, 139 (1985)112. Yu. A. Begantseva, A.S. Malyshev, S.D. Zaitsev, Yu. D. Semchikov, Vysokomol. Soedin. A

44, 560 (2002)113. S.M. Sayyah, A.A. Bahgat, A.I. Sabby, F.I.A. Said, S.H. El-Hamouly, Acta Polymerica 39,

399 (1988)114. E.S.M. Higgy, S.M. Sayyah, I.H. Rashed, E. El-Mamoun, A.M. Hussein, Acta Polymerica

37, 606 (1984)115. A.A. Razik, H. Talaat, S. Fayek, Polym. Degrad. Stab. 46, 41 (1994)116. S.M. Sayyah, M.A. Khaled, A.I. Sabry, I.A. Sabbah, Acta Polymerica 40, 293 (1989)117. T. Cherniawski, Z. Wojtczak, Acta Polymerica 35, 443 (1984)118. Z. Wojtczak, T. Cherniawski, B. Rozwadowska, Acta Polymerica 34, 125 (1983)119. B. Chaturvedi, A.K. Srivastava, Polymer 35, 642 (1994)120. G.I. Dzhardimalieva, A.D. Pomogailo, Kinetika i Kataliz. 39, 893 (1998)121. V.F. Kurenkov, T.A. Zhelonkina, Zh. Prikl. Khim. 77, 310 (2004)122. T. Czerniawski, Z. Wojtczak, Acta Polymerica 41, 201 (1990)123. T. Czerniawski, Z. Wojtczak, Acta Polymerica 42, 277 (1991)124. T. Czerniawski, Z. Wojtczak, Acta Polymerica 43, 219 (1992)125. V.P. Prokop’ev, B.I. Utei, L. Kh. Khazryatova, E.V. Kuznetsov, Vysokomol. Soedin. B 19,

222 (1977)126. E.A. Gonyukh, E.V. Kuznetsov, L. Kh. Khazryatova, V.P. Prokop’ev, N.A. Akhmerov, Izv.

Vyssh. Ucheb. Zaved. Khim. Khim. Tekhnol. 27, 1070 (1984)127. V.A. Kabanov, V.P. Zubov, Yu.D. Semchikov, Complex-Radical Polymerization (Khimiya,

Moscow, 1987)128. N.A. Ghamen, N.N. Messiha, N.E. Ikladious, A.F. Shaaban, J. Appl. Polym. Sci. 26, 97 (1981)129. A.F. Shaaban, A.A. Mahmoud, J. Appl. Polym. Sci. 36, 1191 (1988)130. B.P. Agrawal, A.K. Srivastava, Polym. Eng. Sci. 34, 528 (1994)131. P. Shukla, A.K. Srivastava, Polymer 35, 4665 (1996)132. P. Shukla, A.K. Srivastava, Polym. Int. 41, 407 (1996)133. A. Baccante, R. Quaresima, S. Lora, G. Palma, R. Volpe, B. Corain, J. Appl. Polym. Sci. 67,

11 (1998)

Chapter 6Polymer-Analog Transformations in Reactionsof Synthesis of Metal Macrocarboxylates

The application of polymers in modern technology, of concentration and isolationof metal ions from solution, water preparation, water purification, processes ofremoval, concentration, and separation of metal ions (including heavy), and cataly-sis, is determined to a great extent by the ability of metal ions to form stable contactswith functional groups of macromolecules as sorbents. They appear as a result ofthe creation of a system of electrovalent and coordination bonds between metal ionsand certain groups of polymers, with formation of new polymer systems – macro-molecular metal complexes (MMC).

All organic polyacids are capable of forming in alkaline, neutral, and low acidicmedia quite strong metal complexes. Thus, polyacrylic acid (PAA) binds Cu(II)much stronger than its low molecular weight analogs. This process can proceedwith ionized as well as with nonionized carboxylic groups. In the former case, con-tribution from ionic component into the total coordination bond energy becomesthe definitive [1, 2]. Carboxyl groups containing polymers can be utilized in com-plexation processes in combination with micro- and ultrafiltration [3]. For example,PAA (mol. mass 30,000) is used for the removal of Zn2C and Ni2C ions from wateron a polysulfonic membrane with retention coefficient of 97–99% [4]. This pro-cess is competitive with osmosis, nanofiltration, electrodialysis, liquid membranes,and so on.

The binding of metal with complexing agents of natural systems is of particularimportance, since functioning of transitional metal ions in biological systems, trans-port, and assimilation of metal ions in living organisms are based on the binding ofthe ions by functional groups of biopolymers. Polycarboxylates are widely used ininterdisciplinary areas, such as ecotoxicology, water chemistry, plant nutrition; theyare included into protein formations. Thus, interaction of Ca2C ions with COO�groups of a protein results in a change of biopolymer swelling and is a critical stageof blood coagulation, irritation, and contraction of nerves and muscles, cell move-ment [5, 6]. These macroligands have received broad utilization for the preparationof new types of detoxicants, immobilized ferments, pharmaceuticals, and so on.

Chemical reactions in systems polyacids–metal salt (metal ion) are calledpolymer-analog transformations if during the reactions the nature of carboxyl


145

146 6 Polymer-Analog Transformations in Reactions of Synthesis of Metal Macrocarboxylates

groups bound with the main chain changes, while the length and the structure of themain chain skeleton of a polyacids remain the same. In other words, these reactionsdo not involve the polymer chain, just its side groups [7].

6.1 Complexation of Metal Ions with Macromolecular Ligands

The efficiency of formation of macro complexes and stability of the systemion–polymer depend on the number and the energy of electrovalent and coordi-nation bonds, hence, from the charge, coordination number and the nature of theion, as well as from the number, nature, and the arrangement of charged groups andelectronegative atoms in the macromolecule, i.e., from the chemical structure of thepolymer.

Analysis of interactions in such systems can be approached differently, de-pending on what is considered the central particle: a macroligand or a metal ion.Thus, two approaches for the calculation of equilibrium constants in the systemshave been developed. A method based on an approximation of an independent in-teraction of each unit of macromolecule with low molecular weight compound iscalled the Scatchard method, and an approach counting mutual effects of separatechain units (cooperativity) is called the Hill method [110].

Subsequent addition of metal ions can be described by a general scheme:

LMi�1 CMKi ! LMi (6.1)

where LMi is a chain containing i of attached M. Therefore

Ki D ŒLMi �

ŒLMi�1�ŒM�(6.2)

Thus, the total complexation constant displayed through current concentrations ofchains, [L], and a metal, [M], is equal to

K D ŒLMi �=ŒL�ŒM�i Dj DiY

j D1

Kj : (6.3)

Material balance equations for concentrations of the starting components [L]0 and[M]0 can be presented as follows:

ŒL�0 D ŒL�C ŒL�

iDNX

iD1

Ki ŒM�i ; (6.4)

ŒM�0 D ŒM�C ŒL�

iDNX

iD1

Ki ŒM�i ; (6.5)

6.1 Complexation of Metal Ions with Macromolecular Ligands 147

where [L] and [M] are current concentrations of polymer and metal ions; N is anumber of monomeric units in the chain. Then the formation function (n) that is anumber of ligand groups per one metal ion is determined as:

Qn D

iDNP

iD1

iKi ŒM�i

1CiDNP

iD1

Ki ŒM�i

: (6.6)

Then it is convenient to use the following equation for the calculation of Keff on theformation of similar type macro complexes:

Keff D ŒML�n�”

ŒL�0

n� ŒMLn�

� ˚ŒM0� � ŒMLn�

� (6.7)

where � is the factor counting the maximum number of units L of the polymerparticipating in the formation of MLn complexes.

An approach based on the consideration of a metal ion as a central particle onthe formation of macro complexes utilizes the Flori principle for indefinitely longchains. It presumes that reactivity of binding centers do not depend on their locationin a polymer chain or in a low molecular weight analog when components of themodel reaction are chosen right.

Assuming that there is only one type of reaction center present, the formationconstant is determined as following:

K D ŒM�b=.ŒL�0 � ŒL�/ŒM�; (6.8)

where [L]0 – [L] is the concentration of unreacted units in the chain, [M]b is theconcentration of the complex.

Since the aforementioned scheme accounts for only the number of bound metalions, the equilibrium constant does not depend upon the molecular weight of a poly-acid. For the calculation of a polyacid formation constant, a variation of the Beurrummethod is most often utilized. In particular, for potentiometric titration a modifiedGregor method is used. For this aim, two main parameters, the concentration offree carboxyl groups (L) and the formation function (n), are calculated. Some of thestep formation constants, Kj , calculated by this method for polycarboxylates andtheir low molecular weight analogs are presented in the Table 6.1. However, dueto some special features of the complexation by polyacids (high local concentra-tion of reactive groups in the bunch, change of the charge and the conformation ofmacromolecules during the reaction, participation of reactive centers from differentchains in metal binding, unavailability of some groups for the binding and so on)the Beurrum method is often not applicable for the description of these processes.


Table 6.1 The successive formation constants of the macrocomplexesand their low molecular mass analogs (cit. on [8])

M lg K1 lg K2 lg K3 lg K4 lg ˇ

Sm(III) 5.7 5.4 – – 11:1

Eu(III) 5.7 5.2 – – 10:9

Pr(III) 5.6 5.2 – – 10:8

Cu(II) 4.8 4.2 – – 9:0

Ni(II) 3.9 3.4 – – 7:2

Co(II) 3.7 3.1 – – 6:8

Sm(III) 6.2 5.9 – – 12:1

Tb(III) 3.86 – – – –Cu(II) 5.9 5.2 – – 11:1

Sm(III) 3.9 3.2 2.9 10:0

Eu(III) 3.8 3.2 2.9 – 9:9

Pr(III) 3.7 3.1 2.9 – 9:7

Cu(II) 3.4 2.9 – – 6:3

The most important characteristic feature of reactions of chain molecules(including polyacids) is their ability to form numerous complexes having thesame chemical composition but different arrangement of the reacted metal ions.This leads to compositional inhomogeneity, namely to distribution by length of thereacted and unreacted blocks. This should be taken into account on calculations ofthe formation constants. If upon metal binding unreacted blocks with the numberof functional groups less than the number required for the binding of a metal ionwere formed, then these blocks will not participate in the reaction. In other words,the concentration of unreacted centers is not equal to the active concentration ofreacting particles.

There are different ways possible for binding q metal ions with a chain containingp functional groups. The number of complexes formed that have a different structureis equal to C

qp (number of combinations of q molecules by p centers). In order to

take these factors into account on the calculations of complex formation constants,the real concentration of units reacted with metal compounds is accounted for [9].Usually metal ions are bound to a macroligand by a few bonds from either one (in-tramolecular) or several (intermolecular complexes) chains. In diluted solutions theintramolecular complexes are preferably formed [7,10], while in concentrated solu-tions and in the matrix the intermolecular ones are preferred. During the formationof intramolecular complexes the first binding can be considered as the second orderreaction (first on each component) and all the following reactions (building of in-tramolecular bonds) are the first order ones. Overall reaction of M with one chainis a second order reaction. Rates of complexation reactions usually are high and itis difficult to isolate experimentally stages of the process. In those relatively rarecases when this was done, the constants Ki were found to increase with the increaseof the binding rate of a metal, that is in contrast to low molecular weight ligands.This result is a manifestation of another cooperative “chain effect”, when the shape

6.1 Complexation of Metal Ions with Macromolecular Ligands 149

of a macromolecule changes upon complexation. The addition of a metal ion to thechain is accompanied not by just this chemical act but also by a change in the “localhardness” of the polymeric chain in the point of its addition, thus resulting in theincrease of reactivity of the polymer, for example, according to this type:

L

L

LL

L

L

LL L L

L

L

LL L

L

L

L L

L+ Mn+K1

Mn+ Mn+Mn+K2 K3

The formation constant for the complex can be presented in the form

K DiDNY

iD1

Ki D �Kj (6.9)

where � D Ki=Ki�1, the cooperativity parameter that shows how big the forma-tion constant is for the current addition in comparison with the previous one. It ispostulated that all subsequent constants except the first one are identical, since prac-tically all the entropy is lost in the first act of addition; the subsequent steps are allintramolecular cyclizations. The value K2=K1 D � D 10�4 � 10�8:

In other words, the coordination causes reshaping of the polymer chain andmakes its conformation more appropriate for further reactivity. As a consequenceof this effect, there is an uneven distribution of metal ions between macromoleculesduring the reaction. Since the first addition act is accompanied by the largest en-tropy loss in comparison with the minimal losses in the subsequent addition acts,the interaction with the chain lasts till the saturation of all potential reactive centers.This results in the coexistence in the reaction volume of both, the macro complexeswith the maximum number of bound functional groups and the unreacted macroli-gands, i.e., the principle “all or nothing” is realized.

The cooperative character of interaction in the systems polymer–metal ion ismade evident by not just the shape change of a macromolecule in solution, but aswas mentioned earlier, by the change of chain charge, by dependence of thermody-namic parameters from the molecular mass, molecular mass distribution, degree ofconversion for functional groups, and flexibility of the chain. Significant influenceon metal ion binding can be produced by hydrophobic, hydrophilic, or electrostaticinteractions between the components. A macromolecule is elongated during the for-mation of charged chains in the result of interaction with MnC with the growth ofthe conversion degree [11]. A macroligand itself can contain positively or negativelycharged atoms that facilitate or prevent binding of metal ions. Therefore, electrolytesolutions are specially introduced for the prevention of electrostatic repulsion.

Thermodynamic characteristics for the interactions of metal ions with polymerreagent are estimated from temperature dependencies K D f .1=T /. As a rule, the


largest contribution into the total change of free energy is made by the entropy part,while the enthalpy part has only slight changes. For this analysis three levels ofspatial arrangement of macro complexes have to be taken [12] into account:

– Local level, that reflects chemical structure of a single binding unit of a metalion with a chain molecule (nature of the metal and carboxyl groups, reactionconditions and so on)

– Molecular level, defined by the chemical structure of a polymer chain (its length,composition of elementary units, shape and conformation of the chain, and so on)

– Supramolecular level, reflecting features of supramolecular interactions of macro-molecules and the degree of their mutual arrangements. This is especially relevantfor studies of metallopolymers in the solid phase, for example, those obtained bylyophilic drying of the corresponding solutions, when the effects of supramolec-ular organization are manifested to higher degree in comparison with solution

By taking into account these three levels of spatial arrangement, the difference inthe free energy on the formation of macro complexes can be presented as follows(assuming the additivity of its components):

�G D �G1 C�G2 C�G3; (6.10)

where �G1, �G2, and �G3 are the free energy differences for local, molecular, andsupramolecular levels, correspondently. Under certain conditions, the free energydifference for one or another level can be neglected, allowing analyzing enthalpy(�H ) and entropy (T�S ) contributions into the �G value for each level in moredetail:

�G D ��H C T�S (6.11)

6.2 Metal Ion Binding by Polyacids

Polymeric acids as macroligands attracted attention of a number of researchersrather early (see, for example, [13–16]). Let us consider the main features of MXn

binding by polyacids with taking into account the structural organization (topology)of a polyligand.

Polymers and copolymers based on acrylic and methacrylic or sulfonic acids areused most often, usage of maleic, itaconic, or others is rare.

The necessary cation can be bound to polymer by either the treatment of its acidicform with the corresponding metal hydroxide, or substitution of a weakly boundcation. For the polyacids the affinity toward metal cations changes in the followingseries: HC >> AgC > NaC.

However, in the vast majority of cases preliminary ionization of the polymericacids is carried out.

6.2 Metal Ion Binding by Polyacids 151

Binding of alkali metal ions by PAA macromolecules increases in the seriesKC < NaC < LiC [17], although from the position of ion atmosphere binding thereverse order should be expected. The normal order follows the law of electrostaticinteractions: a solvated ion with the smallest radius interacts stronger than the onewith the largest radius. The reverse dependence in the case of polycarboxylic acidsattests for their specific binding, according to which the viscosity of aqueous solu-tions of polycarboxylic acid salts increases in the row LiC > CsC.

Binding of small ions with polyions to large extent determines the solubilityof polyelectrolytes in solutions of salts. Typically, introduction of low molecularweight electrolytes into aqueous solutions of polyelectrolytes decreases the solubil-ity of the latter. The stronger the binding of ions with the chain, the stronger is theeffect. Accordingly, solubility of polyelectrolytes decreases most significantly onthe introduction of multicharged counter ions.

Interaction of PAA with divalent cations has been investigated rather thoroughly,since exactly this reaction was put into a base of classical studies of complexationwith participation of macroligands (see, for example, papers [18–21]). Interactionof metal salts with polymer reagents differs significantly from reactions with lowmolecular weight analogs, since they feature the presence of a number of reactioncenters and also are accompanied by a change of conformation and shape of macro-molecules in solution. Successive attachment of metal ions to functional groups ofa polymer (presumed to be a central particle) is considered most often. Strong de-crease in the pH of the aqueous solution of a polyacid occurs upon addition of ametal salt, indicating ionization of carboxyl groups.

R�COOHCM2C K1��*)�� RCOOMC C HC (6.12)

RCOOMC C R�COOHK2��*)�� .R�COO/2MC HC (6.13)

This is manifested by two jumps of the pH on potentiometric titration curves, forexample, for Cu(II), the first jump takes place between the pH values 6 and 8, whilethe second one does at about 10.5. However, these processes typically proceed alongmore complicated routes, including disassociation of a polyacid and hydrolytic equi-libria with participation of the hydroxo complexes, M.OH/n:

R�COOH• R�COO� C HC (6.14)

M.OH/.2�n/�n C nHC • M2C C nH2O

RCOO� CM2C • .R�COO/2M(6.15)

The structure of the binding center can have a different character:

M+CO

Oe

MC

O

O→MC

O

O


The high concentration of HC in the solution facilitates a shift in the two latterequilibria to the right. Hydrogen ions are less likely to undergo the exchange forthe transition metal ions than the alkali metal cations. Therefore, the preliminaryionization of polyacids is carried out to facilitate the exchange. Let us consider thisprocess in more detail on an example of Cu(II) binding with PMAA [22]. EachCu(II) ion interacts with one, two, or four carboxyl groups depending on the ionicstrength and the pH. Adducts with 2:1 composition are formed predominantly at lowconcentration of copper ions, while at high concentration the 1:1 adducts are formed.The stability constant for the 1:1 Cu2C complexes (25ıC; NaNO3 0.1 mol/L, pH 6)with PAA mol. mass 3 � 106 is estimated [23] to be lg K1 D 5:2˙ 0:2.

There are two variants possible upon this: the intramolecular interaction with twocarboxyl groups from the same chain and the intermolecular one with participationof carboxyl groups from different polymer chains. Doubling of the molecular massof PMAA upon the interaction with Cu(II) means that binding of divalent cationsby ionized PMAA is conducted through bridges between two polymer chains [24].In other words, dimerization of a polyacid is a consequence of covalent bindingin such systems. The same phenomenon is observed in the PMAA–Zn(II) systemwhen the molecular mass of PMAA increases from 0:47� 106 to 1:025� 106 in theproduct [25]. The composition of the compounds formed depends on the concentra-tion ratios of the reacting components. Products with 1:1 composition are formedat low concentration of Zn (degree of neutralization is 0.3–0.75), while at high con-centration the 2:1 products are formed. Complexes with 2:1 composition are morestable than the 1:1 complexes. The question of binding of counter ions is important.The binding is carried out by formation of ion pairs or complexes with participa-tion of the counter ions and the charged portions of the polyion. The correspondingbound portion is thus discharged.

Typically, it is difficult to separate experimentally the two types of binding.The presence of a specific binding was proven by the studies of interaction ofdifferent counter ions with the same polyion. Binding of cations by polyanions isdetermined by the size of the charged group of the polyion, radius of the hydratedand nonhydrated forms of a counter ion as well as their solvation energy.

The pH value of the medium is also important. At low pH values, the PAA chainhas an elongated shape due to repulsion between the negatively charged COO�groups and metal ions bind to one or two neighboring groups. At the pH < 4.5 themacromolecular tangle compresses, and a metal ion can coordinate to 2–4 carboxylgroups. PMAA forms with Cu2C ions three types of complexes, depending on theconcentration of copper and the degree of neutralization of carboxyl groups whenexchanged interactions are realized [26]. These are mononuclear, tetragonal, andpolynuclear associates (clusters that are described below in the grafted fragmentsPE-gr-PAA) and even Cu2C nitrate adsorbed on the surface of PMAA at lyophilicdrying. Upon neutralization of PMAA solutions with NaOH, polynuclear clustersare destroyed already at ˛ D 0:1 and dimeric complexes are formed. Interestingly,PAA that has a similar structure behaves differently. Concentration of polynuclear


complexes increases and mononuclear ones decreases with the increase of the ˛

value. Cu(II) forms with the ionized PMAA and PAA complexes of the D2h andD4h symmetry (dimers) depending on the pH [27]:

C

O O

Cu

OOC

C

O O

Cu

OOC

C

O O

Cu

OOC C

O O

Cu

OO

C

D2h D4h

Thus, two main structures of the coordination polymers are formed. The first oneis the square planar structure of Cu2C with four oxygen atoms of two carboxylgroups, the coordination number (CN) of the copper is 4 and the Cu2C–O distanceis 0.196 nm. The second one is the binuclear coordination structure Cu2C–Cu2C, theionic pair with 8 oxygen atoms of four carboxyl groups. In this structure the Cu2C–Odistance is equal 0.196 nm and the Cu2C–Cu2C one is 0.264 nm [28]. These coor-dination linked network structures are more stable than their low molecular weightanalogs or the precursor ammonia complexes.

O

C

O

Cu

O

O

C C

O

O

CuO

OC

CO

OCu

O

OC

CC

It is necessary to take into account that typically structures of this type are dynamicformations and may change in solution with time, transforming into more stableones. There are a number of examples of this. For example [29], Cp2TiCl2 whenin slight excess forms with the copolymer, poly(styrene-co-methacrylic acid), Mw

36,000, Mw=Mn D 1:7, in THF a soluble product (Mw 41,000, Mw=Mn D 1:9).All attempts to remove the excess of Cp2TiCl2 by reprecipitation of metallopolymerled to cross-linking of the product.

It was demonstrated by different physico-chemical methods (including spectralones coupled with the dialysis) [30], that interaction of Ca2C ions with PAA occursthrough a series of intermediate stages, such as: the starting NaC ionic complexbinds to carboxyl group in bidentate fashion (a), then intermediate monodentateCa2C complex is formed (b), pseudo bridge complex with H2O (c), pseudo bridgecomplex with NaC (d), and, finally, bidentate chelate complex (e).


Ca++

Ca++

Ca++

O

O O

O

O

OO H

H

Ca–

++

Na

Ca+

O

O Ca+

Na+

a

b

ce

d

O

OCa

+

The interaction of organometallic compounds with polyacids, for example, the in-teraction of diethyl zinc with copolymer ethylene-co-methacrylic acid (HA) [111]takes place through the series of equilibrium transformations, that include formationof acidic dimers, formation of tetracoordinated zinc carboxylates, then (with the ex-cess of acidic groups) hexacoordinated zinc carboxylates, and, finally, formation ofthe salt of hexacoordinated zinc(II):

2AHK1��*)�� ŒAH � � �AH� acid dimer (6.16)

ZnEt2 C 2AHK2��! ZnA2 C 2EtH tetracoordinated zinc carboxylate (6.17)

ZnA2 C AHK3��*)�� ŒZnA3��HC hexacoordinated zinc carboxylate (6.18)

ZnA2 C 4AHK4��*)�� Œ.AH/2 � � �AZnA � � � .HA/2� Zinc acid salt (6.19)

Since the stability of complexes depends on many factors, some formal (empirical)equations were suggested that connect molecular mass of PAA (1:4 � lgN � 2:4,where N is a number of monomeric units) with the complexation constant for cal-cium and magnesium ions and the solution ionic strength (0 � I � 1), and thedegree of protonation (˛). The formation constant for Ca2C complexes is higherthan that one for Mg2C: at I D 0:1 mol L�1 (NaCl), log N D 1:8 and ˛ D 0:5 thelg KCa2C

2 D 4:43 and the lg KMg2C2 D 4:24 [31]. For the pair Cu2C and Ni2C the

formation constants for ML2 complexes (ˇ) are equal 6.3 and 5.4, correspondingly(for the calcium at these conditions ˇD 4:6). Mg2C ions form less stable bonds withPAA than Ba2C, Sr2C, and Ca2C ions do. Changes in the viscosity and the specificconductivity of the polyion charge observed upon the neutralization of MgO aresmaller for the PAA than those for the PMAA. Upon titration of 0.02 M solution ofPAA with barium hydroxide [32] the transition from loose to compact tangle wasnoted in the region 0:3 < ˛ < 0:55 and the difference in the free energy for thesestates was calculated: �Gı=N D 156–173 cal/mol.

The series of the stability constants (lg K2) for the metal ion complexeswith PAA or PMAA obtained under the same conditions is presented [33] as


the following: Cu2C�Ca2C�Mg2C. Since calcium ions bind two neighboringcarboxyl groups, their lg K2 has the same value as in the case of dicarboxylicligands.

There were attempts (in particular, on an example of Ca2C ions binding [34])for searching for equations connecting the protonation constant and the disassoci-ation constants for macrocomplexes as a function of the ionic strength (I ) and thetemperature (T , K) according to the type:

pKH D 4:856� 0:984 I 1=2C 0:253 I � 198:7=T for protonic dissociation (6.20)

andpKCa D 3:968� 2:671 I 1=2 C 0:750 I � 1102:3=T: (6.21)

Complexation of Al3C ions with a statistical copolymer of acrylic and maleic acids(composition 0.7:0.3, molecular mass 92,000) was investigated in detail by titrationmethod as well as by applying the stopped-flow technique [35]. Low molecularmass analogs, such as glutaric and tricarballylic acids, were used as models for thecomparison analysis.

COOH

CH2CH2

CH

COOH

COOH

The main conclusions were, that the dominating part of the Al3C complexesare intrasphered and monodentate, they include neighboring COO� groups and thedeprotonation constant of the macroligand, pKd D 3:0, (the maximum degree of de-protonation is achieved at the pH equal 3.6), is significantly lower than those for thelow molecular weight analogs (Table 6.2). Substitution of a water molecule insidethe hydration shell of the aluminum ion by a carboxyl group of the macroligand isthe rate-determining step. The rate constant for this reaction (k1 D 3:1 s�1) is alsolower than those for the model ligands. A positive value for the change in activationentropy indicates the low hydration degree in the intermediate complex. Formationof triple charged cations, similar to the ion pair type that includes polyacrylate ion,occurs upon the neutralization in the Co3C – PAA system. Their formation is sup-pressed upon introduction of an electrolyte.

Q – described of the outer sphere association. Q depends only on electrostativeinteraction.

In addition to the potentiometric titration method, the stopped-flow technique,different variations of spectral and electro-chemical methods, there are also otherways for the quantitative evaluation of the efficiency of the formation of macro-molecular metal complexes. One of them is based on the effect of quenching ofthe luminescence of macromolecules with luminescence labels (0.1–0.3 mol% ofgroups of the 9-alkylanthracene structure) by transition metal ions in dilute solu-tions under the conditions of ionization of all carboxyl groups [36]. Under these


Table 6.2 Thermodinamic and kinetic data for the complexation of Al3C withcarboxylates at 298 K [35]

Glutaric acid Tricarballylic acid Polycarboxylic acid

pKa1 4.37 3.72 4.0pKa2 5.50 5.05 5.9pKa3 – 6.6 7.8pKd 5.4 3.5 3.0lg Ki 1.15 1.15 0.54lg .Q0 dm�3 mol�1/ 1.3 1.3 3.3k1Œs�1� 37 19 3k

�1Œs1� 2.7 1.4 1.0k2[mol dm�3 s�1] 7:0 � 10�2 3:9 � 10�2 8:0 � 10�4

k�2[mol dm�3 s�1] 5:0 � 10�3 2:8 � 10�3 2:6 � 10�4

�H 0i [kJ mol�1] 20 28 19

�S0i ŒJK�1 mol�1� 90 115 72

�H 0d [kJ mol�1] 0 0 0

�S0d ŒJK�1 mol�1� �100 �67 �57

�HC

1 [kJ mol�1] 70 92 78�S

C

1 ŒJK�1 mol�1] 30 70 20�H

C

2 [kJ mol�1] 120 70 63�S

C

2 ŒJK�1 mol�1] 90 30 �100

conditions for the complexes of AgC, Cu2C, and Ni2C with carboxyl containingpolymers and copolymers in aqueous saline solutions at 25ıC the stability constant,Kst, is higher than 108 [37]. A portion of Cu2C ions forms electrovalent contactswith one ionized carboxyl group in the ratio “ > 0:5 (ratio of molar concentra-tions of metal ions and carboxyl groups at different fixed concentrations of thepolymer in solution). Then, the Kst values decline to 105–103. Since electrova-lent interactions play a definitive role in the formation of these macrocomplexes,the complexes can be destroyed upon the increase of ionic strength of the solution.Thus, the Kst is diminished upon addition to the solution of a neutral salt, NaCl,(Kst is equal 6 � 107 and 1 � 107 at i D 0:1 and 0.5, correspondingly). The struc-ture of carboxyl containing copolymers (isomeric structure of carboxyl containingunits) also affects the stability of MMC. Compacting of macromolecules occurs dueto enhancement of intramolecular contacts (upon mutual compensation of carboxylgroups and metal ions). Infrared spectra provide significant information regardingthe structure of carboxylate units. The frequency �COO� D 1;580 cm�1 is observedin the IR spectra for the products that do not contain bridging COO� groups, whilefor those with bridging carboxyl groups the frequency � D 1;520–1;560 cm�1 isobserved. The frequencies �as and �s equal to 1,390–1,440 and 1,300–1; 340 cm�1,correspondingly (Table 6.3).

Characteristic adsorption bands for the valent oscillations of COO� in the IRspectra for the solution mixture (1:1) of metal nitrates (1 mol/L) and 25% PAA in thecase of Al.NO3/3 appear at 1;616 cm�1 .�as/, 1;449 cm�1 .�s/, �� D 167 cm�1;


Table 6.3 The stretching frequencies (cm�1) of COO� –groups in the IR spectra of MXn adducts with PAA [13, 38]

M �CDO �asCOO� �sCOO�

1,700 1,437 1,400 1,336Fe(III) 1,560 1,440 1,400 1,313Cr(III) 1,546 1,440 1,394 1,324Co(II) 1,546 1,438 1,390 1,307Ni(II) 1,536 1,436 1,390 1,300Pd(II) 1,520 1,440 1,393 1,340

1,640Al(III) 1,616 1,449Fe(III) 1,632, 1,526

and for the Fe.NO3/3 in the same system they appear at 1,632, 1526 cm�1 .�as/,1; 450 cm�1 .�s/, �� D 182 and 76 cm�1.

The interaction mechanism and the structure of ionic bound carboxylates of rareearth elements (REE) are investigated in detail (see, for example, [39, 40]). Forma-tion of intrachain complexes that have a fragment of 10–13 monomeric units perone metal ion takes place upon addition of trivalent REE ions [Tb, Ce, La, Eu, Nd,and others] to aqueous solutions of PAA, PMAA, or polyglutamic acid. The state ofEu(III) ions in their polycarboxylates, in particular the number of water moleculesin the first coordination sphere of the metal ion, was studied by the laser inducedfluorescence [41]. A cage from carboxylate ions is formed around the metal ionwhen the ratio ŒCOO��=ŒEu3C� is 20. Each metal ion is surrounded by between5.5 and 8 water molecules (pH D 5.5) and the pH dependence indicates the changeof conformation of PMAA depending on the number of water molecules aroundthe metal ion. Complexes of Ce(III) with PAA, especially with the low molecularweight one, were utilized [42] for the preparation of CeO2. Only COO� groups takepart in the binding of Tb(III) by the hydrolyzed polyacrylamide; amide groups donot participate in the reaction [8].

Platinum group metals easily interact with polymeric acids, the type of the bondformed being determined to a substantial extent by their nature [8,43,44]. Thus, thebridging binding is more typical for ruthenium compounds: polymer bound ruthe-nium acetate has a structure of �3-oxo-metal acetate complex, while rhodium (I)gives nonbridging complexes (Scheme 6.1). Poly(carboxylato)hydrocarbonyltrip-henylphosphineruthenium (II) and poly(carboxylato)triphenylphosphineruthenium(II) chloride were synthesized by the reaction of benzene solutions of RuH2.CO/

.PPh3/3/ or RuCl2.PPh3/ with copolymers of acrylic acid and ethylene, maleic acidand alkyl- or arylvinyl ethers [45]. In the latter, the carboxyl groups of maleic acidfragments act as either mono- or bidentate binding ligands. Chemical and physicalproperties of these macromolecules are determined by hydrophobicity, electronega-tivity, and volume of the ether fragments. Compounds of Rh and Pd are efficientlybound to copolymers of styrene and maleic acid [46].


~CH2CH2 CHCH~

COO

~CH2 CH~

CH~

C

~CH2 CH2CH

~CH2 CH~

COO–

6-nRu3(OCOCH3)nL3]+

(n = 1÷5L = μMΦA)

μMΦ

A – C

H3 O

H

O

OO O

L

L

CO

C

O

~CH2 CH~

C

~CH2 CH~

C

O

O

Rh(PPh3)x (x = 1÷3)

5-x

PPh3

PPh3

PPh3

PPh3Ru

Ru

(L = CO, PPh3)

H

O

O n MCI3–n

CH2 CH

C

C

CH2 CH CH2 CH

C CO O O

O

O

O

O

O

O

O

U

N

mn

n–m

O OM

O

O O

CH2 CH

C

m–I

O O

CH2

H2O

H2OH2O

CH

O

O

O

O

O U

N

H2O

C

I

CH2 CH

C O

O

O

OOOO

C

OC Ru(CO)3

RuCI(CO)3

OO

O

O

O

O U

C

C

C

n

CH2 CHn

CH2 CHn

CH2 CH CH2 CHm

O O

CH2 CH

C

m

CH2 CHm

O

O

O

C

CH2

H2O

H2OH2O

CH

OO UH2O

O

OO

O U

C

I

CH2 CHI

MOCOCH3

UO2(NO3)2

C3 H

7 OH

RhH(PPh3 )

4

RuC

I3 • 3H2 O

M(O

CO

CH 3

) 2 (M

= N

i, C

o,C

u)

C 2H 5

OH

– H

2O

CH

3 OH

[RuC

I2 (CO

)3 ]2

RuH2L(PPh3)3

C3H7OH / C6H6

MC

I 3(M

= L

a, C

a, N

d)

Scheme 6.1 Formation of macrocomplexes via carboxylic group of polymer acids

In principle, a similar mechanism is realized also upon binding of complexes off -elements, for example UO2.NO3/2 � 6H2O [8, 47–49]. Interaction of uranyl ionswith carboxyl groups leads to a change of chemical and physical nature of neigh-boring groups, so that it facilitates involvement in the process of subsequent groups.Different variations of immobilization are observed: UO2(II) ion can be attached totwo carboxyl groups that are monodentate or give chelates with formation of linkedor not linked bridging structures (Scheme 6.1). About 85% of carboxyl groups arechelated, which is caused by steric factors allowing only limited number of carboxylgroups to participate in this interaction. Uranyl complexes with PAA have hexag-onal (bipyramid) structure that includes two intrasphere H2O molecules per eachuranium atom.

There are numerous macrocomplexes with derivatives of carboxylic acids. Themost abundant are, in particular, macrocomplexes of Co(II), Ni(II), Cu(II), Fe(III)with copolymers of acrylonitrile (or methacrylonitrile) and methacrylic acid [50]and Cu(II) with copolymers of maleic acid and ethylene, styrene, or n-butylvinylether [51]. Both carboxyl groups of maleic acid fragments participate in the inter-action that is accompanied by local changes around the chain and its conformationaffects strongly neighboring groups upon the complexation. Copolymers of acry-lamide and acrylic acid (prepared by polymer analog transformations upon hydrol-ysis of polyacrylamide) efficiently bind Fe(III), Cu(II), Ni(II), Cr(III), and othercations. Macrosalts of Cr(III), Fe(III), Ni(II), and Co(II) with polyethylene gly-

6.3 Metal Ion Binding by Stereoregular Polyacids 159

col methacrylate phtalate are of interest, as well as are the reaction products ofpolyfunctional esters with amphoteric metal oxides [52]:

ROCOR'COOn

nROCOR'COOHO

ROCOR'COOHOn 2

M

HOnH + MOROCOR'COO

HO M OHH

Formation of metal hydroxocarboxylates is the first act of these interactions, whilethe next one is formation of metal dicarboxylates. More deep processes includecoordination of terminal hydroxyl or carbonyl groups by a metal, leading to the in-crease of molecular mass of the products formed. Involvement in the reaction ofreactive groups of these multifunctional macroligands takes place in the follow-ing order [53]: –COO�> diol OH groups > polyether terminal groups > polyethercarbonyl groups.

6.3 Metal Ion Binding by Stereoregular Polyacids

Investigation of specifics of MXn binding by stereoregular polyacids is of significantinterest, although these data are extremely limited. Out of general consideration,it can be suggested that distinctive configuration of a polymer chain can affect thestructure of a macrocomplex, and the lower the flexibility of the ligand the strongerthe effect of chain macrotacticity will be. A big difference between syndio- andisotactic PMAA in selective sorption of univalent metal ions was noticed a whileago [8]. Activity of sodium ion changes in the series iso- > syndio- > atactic for alldegrees of neutralization and regardless of the molecular mass and the concentrationof a polyacid. Formation of macrocomplexes with bivalent metal salts also points tothe big importance of microstructure of polyacids, for example PMAA. The featureof metal ions interaction with the stereoregular PMAA, is that neighboring carboxylgroups of the chain are involved in the macro complex formation. Each Cu (II) ionreacts with two neighboring carboxyl groups of one chain of the isotactic PMAA.It was established by methods of potentiometric titration, dialysis, and viscosime-try that interaction of Cu(II), Mg(II), and Zn(II) ions with the isotactic PMAA ofvarying degree of neutralization (˛ D 0:3� 0:9) takes place according to two-stepscheme [112]: At high concentration of Cu(II) the products of 1:1 composition areformed, while at low concentration those of 2:1 composition are formed. The char-acteristic viscosity, [�], increases from 2.0 to 9.9 for the isotactic PMAA, dependingon the ˛ value, and for the macrocomplexes of PMAA with Cu(II) from 0.4 to 3.0(see Fig. 6.1). These facts are explained similarly to the cases discussed above bycompression of PMAA macromolecules that increases in the series Mg(II) < Zn(II)< Cu(II).


Fig. 6.1 The characteristicviscosity of the isotacticPMAA vs. neutralizationdegree (˛) undoneutralization without salts(1) and in presence of Mg(II)(2), Zn(II) (3), and Cu(II)(4) ions

0.20

2.0

4.0

6.0

8.0

0.4 0.6 0.8 a

1

2

3

4

[h], L / g

Fig. 6.2 Thermodynamicparameters of metal ionsinteractions with syndio-(1, 3) and isotactic (2)PMAA. (1,2) the change ofenthalpy, (3) enthropy

Mn Fe Co Cu Zn CdNi30

40

50

60

0

2

2

3

1

4

6

ΔS, K

cal/

mol

K

ΔH, K

cal/

mol

The nature of reacting cations also plays an important role upon their bindingwith the iso- and syndiotactic polymethacrylic acids (PMAA). Thus, the isotacticPMAA is 1.5 times more reactive toward binding of Cu(II) than the syndiotacticone [2, 54], whereas in the case of Mg and Na, the opposite is observed. Upon pre-cipitation of PMAA from solution by Cu(II) ions, the isotactic polymer precipitatesfirst at the concentration of Cu(II) three times lower than that one required for pre-cipitating the syndiotactic polymer. Such an influence of stereo regularity on theprecipitation is not observed for the more flexible PAA macromolecule.

The interaction of Mn, Co, Ni, Cu, Zn, Cd, and Mg ions with isomeric polyacidsis an endothermic process, and therefore, complexes are stabilized due to relativelylarge entropy changes. It is obvious from the Fig. 6.2, that the �H value for thecomplexes of isotactic PMAA is always higher than the one for the syndiotacticPMAA (with the exception of the Cu(II) complexes) and the isotactic complexesare more strained.

6.4 Peculiarities of MXn Binding by Cross-Linked Polyacids 161

Table 6.4 The thermodynamic data of Cu(II) and Mg(II) ions complexation with syndio- andisotactic PMAA

MacrocomplexK � 10�7

(L/mol)��G(kcal/mol)

�H(kcal/mol)

�S(kcal/(mol K))

Cu(II)-syndiotactic PMAA 400 13.2 5.1 61Mg(II)-syndiotactic PMAA 1.0 9,6 0.14 32.5Cu(II)-isotactic PMAA 1,200 13,9 3,8 59Mg(II)- isotactic PMAA 0.4 9.1 0.8 33

The differences between the magnesium and the copper complexes (Table 6.4)are entirely caused by their nature: Cu(II) forms covalent type compounds, whileMn(II) forms ionic ones with lower steric constrains and the lower �H values.

The high values of �H and �S for the Cu(II) complexes are due to the releaseof H2O molecules upon their formation. Two water–metal bonds are destroyed dur-ing this process, leading to the entropy increase. According to UV spectroscopydata Co(II) binds with three carboxyl groups of one polymer chain. This is ex-plained by the stronger charge redistribution on the polymer anion (contributionof a covalent component in the formation of Co(II) carboxylates is lower than in thecase of Cu(II)). The data of equilibrium dialysis indicate that the iso-PMAA bindsCu2C3 times stronger than the syndiotactic one, while the binding of Mg2C by theiso-PMAA is weaker (especially at high ionization degrees). Cu2C forms covalentcomplexes of strict geometry, while Mg2C forms ionic in which it is less deter-mined. That can lead to different dependence of the degree of association of theseions with PMAA upon the stereoregularity of the polymer. Many other cations aremore efficiently bound by the syndio-PMAA than by the iso- isomer, the atacticPAA holding the intermediate position. Investigations of complexation processes ofPMAA often help evaluate its conformational state. Further studies are needed forestablishing of general peculiarities of metal ions binding by isomeric polyacids, inparticular analogs of PAA and PMAA.

6.4 Peculiarities of MXn Binding by Cross-Linked Polyacids

Significant attention is paid to this subject in literature (see, for example, a mono-graph [55]), in particular, due to a wide spread and systematic investigation ofcarboxylic cationites and ampholites. The following main features are observedupon binding of MXn by these macro ligands. The composition of coordinationcenters depends on the preliminary treatment of the polymer, the degree of ioniza-tion (˛) of carboxyl groups. At the ˛ value close to 0, structures with the maximumnumber of nonionized carboxyl groups dominate. At high ˛ values as a result of sig-nificant electric field the ionic type of M(II)–PAA bond is dominant. A coordinationcenter can include both, protonated and deprotonated groups. For example, there arefour carboxyl groups in the plane of a square and two water molecules on top of anoctahedron in the Cu.RCOO�/2.RCOOH/2 � .H2O/2 [56]. The degree of binding


of functional groups by a metal, i.e., concentration of the bound metal (polymer“loading”) also substantially affects the composition of the products formed. TheKst value decreases with an increase of the degree of binding of functional groupsby a metal. This is caused by energetic heterogeneity of the surface, stereochemical,and geometrical defectiveness of the centers formed (including the lower numberof available ligand groups). Therefore, an important role is given to the changeof mobility of a polymer matrix by controlled cross-linking, introduction of otherfunctional groups into polymer, and so on. Structural features of linked ligands canintroduce certain changes into the composition, structure, and stability of the prod-ucts formed, leading to the inversion of stability series. Thus, stability constantsof complexes with the PMAA without cross-linking decrease in the series Cu(II)> Zn(II) > Ni(II) > Co(II), whereas for the cross-linked PMAA the stability ofcomplexes (probably due to formation of Zn(II) complexes of tetrahedron struc-ture) changes in another sequence: Cu(II) >> Ni(II) > Zn(II) [2]. Typically, mostlymixed diffusion mechanism of binding is realized. Contribution of external or in-ternal diffusion into kinetics of the process can change depending on the degree ofcross-linking of these carriers, concentration, and the nature of MXn in the solution.Perhaps, the same mechanism takes place also upon attachment of MXn to carboxylcontaining fragments of “mosaic” gels [57].

Thus, the diversity of binding forms of transition metals by carboxyl containingpolymers, provides significant possibilities for the fine tuning of composition andstructure of coordination centers and the bond types realized there. The desired re-sults can be achieved by varying the conditions of binding (preliminary treatment ofthe polymer, the pH and ionic strength, the nature of a media, concentration ratios,and so on).

6.5 Formation of Macrocomplexes with GraftedPolycarboxylic Fragments

Grafted polymers is a type of copolymers. Their distinction is that practically allreactive groups are located on the surface, and are accessible to reagents includingmetal salts in the suspension binding method. Ion exchange membranes are ob-tained by grafting acrylic and methacrylic acids (see, for example, [58]). It has beendemonstrated [59] on the example of Rh3C binding, that strong binding of evensmall amounts of a metal (0.005–0.08%) improves thermal, electrical, and opticalproperties of copolymers.

The general scheme of binding of M.OCOCH3/2 in aqueous alcohol suspensiononto polyethylene with grafted polyacrylic acid (PE-gr-PAA) can be presented asthe following [60, 61]:

CH2 CH

COOH

m + M(OCOCH3)2 CH2 CH2 CH2 CH2CH

COOH

m–(l+n) CH

COOH

lCH

C

CH

CO OO O

M

n

M = Cu, Ni, Co

6.5 Formation of Macrocomplexes with Grafted Polycarboxylic Fragments 163

According to the scheme, part of the grafted carboxyl groups do not take partin the reaction and the M(II) attachment is carried out by one carboxyl group withthe formation of mixed ligand products (monosubstituted form C1), as well as bytwo (disubstituted form C2 – “anhydride” cycles) carboxyl groups of the graftedfragments. Equilibrium for this reaction is established almost immediately aftermixing the components. With the increase of temperature (283–363 K) the amountof bound M(II) increases almost linearly (Table 6.5). An increase of the molar ratio,ŒM.II/�0=ŒCOOH�0, enhances the rate of carboxyl groups participation in the reac-tion. However, a significant portion of them is not involved in the process even withthe excess of M.OCOCH3/2. The concentration dependence (Fig. 6.3) of the M(II)binding upon the ratio ŒM.II/�0=ŒCOOH�0 has the Langmuir type. Its analysis by ap-plying the transformed Langmuir equation for the isotherm of localized adsorptionlead to K D 300 L/mol and k D 0:35.

Table 6.5 The characteristics of Cu(II) ions binding with PE-gr-PAA [60]

[Cu(II)]CB Concentration, mol. partT , K wt% mmol/g [�COOH] C1 C2

2:1 333 2.48 0.39 0.28 0.06 0.661:1 333 2.07 0.325 0.44 0.08 0.480.5:1 333 1.51 0.24 0.53 0.01 0.460.3:1 333 1.37 0.22 0.56 0.01 0.430.2:1 333 0.94 0.15 0.70 0.002 0.2950.1:1 333 0.55 0.087 0.83 0.002 0.170.05:1 333 0.29 0.045 0.91 0.003 0.090.02:1 333 0.20 0.032 0.93 0.001 0.0641:1 293 1.96 0.31 0.43 0.05 0.521:1 313 2.03 0.32 0.43 0.07 0.501:1 353 2.35 0.37 0.37 0.11 0.521:1 363 2.69 0.42 0.25 0.09 0.66

Note: The content of grafted fragments is 1 � 10�3 mol/g

40

0.2

0.4

8[Cu]·102, mol / L

4 8[Cu]·102, mol / L

[Cu]

b·1

02 , m

mol

/g

0

0.1

0.2

[Cu]

/[C

u]b

a b

Fig. 6.3 The concentration dependence of Cu(II0 binding upon the ratio ŒM.II/�0=ŒCOOH�0. (a)the dependence of ŒCu�b D f ŒCu�; (b) ŒCu�=ŒCu�b D f ŒCu� (Langmuir isotherm)


ŒCu.II/�=ŒCu.II/�CE D 1=KC .1=k/ŒCu.II/� (6.22)

where [Cu(II)] is the concentration of Cu(II) in the solution, k is a constantcorresponding to the saturated adsorption of Cu(II) by carboxyl groups.

These values attest that the grafted fragments during the interaction with MXn

behave similarly to homopolymers by the degree of functional groups availability (atleast under these conditions). The observed peculiarities are also retained upon theincrease in the amount of grafted PAA from 1.5 till 11.0 mass% (0.2–1.5 mmol/g,average thickness of a grafted layer is 4–28 nm).

It is important to establish the correlation between the forms C1 (one point bind-ing of M(II)) and C2 (cyclic binding) as a function of reaction conditions. Thiswas done by using tritium labeled salts, M.OCOC3H3/2, during the immobilization[61]. The radioactivity of the final product will be determined only by the contentof the form C1. The ratio between the immobilized transition metal and the radioac-tivity of the product characterizes the content of the products C1 and C2. It is seenfrom the Table 6.3 that with the increase of Cu.OCOCH3/2 concentration in solu-tion, the portion of C1 increases. However, in the case of ionized PAA in the systemsPE-gr-PAA-M(II), the contribution of these structures does not exceed 8.2 mol% forthe Cu(II), which is in contrast to the preferential formation of 1:1 products no-ticed in many papers. That is, this reaction is strongly shifted toward formation ofcyclic products of the C2 type. Most likely that similar to the isotactic PAA, thecyclization involves neighboring units of the same grafted chain. Upon temperatureincrease, the ratio of the C1 and C2 forms increases slightly due to the increase ofthe portion of carboxyl groups involved in the reaction.

Note, that up to 70% of carboxyl groups participate in the reaction, due to the sol-ubility of the grafted layer under the reaction conditions. The situation of insolublepolymer support – soluble grafted layer is modeled in these systems. In other words,in the systems based on PE-gr-PAA advantages of both soluble (relative flexibilityof the grafted chains, availability of the functional groups, high their concentrationin the polymer domain and so on), and tridimensional linked (easiness of productisolation from the reaction volume, predomination of structurally homogenic com-plexes and so on) polymers are realized.

Other peculiarities take place on the interaction of MXn with PE-gr-PAA innonaqueous media [62], such as thickness of the grafted layer induces significantinfluence on the effectiveness of the binding. Since outer fragments are more avail-able for the reaction than the inner ones, the effectiveness of the reaction decreaseswith an increase of the degree of grafting. In particular, almost each carboxyl groupreacts with the VO.OC2H5/3 [or with the Ti.OC4H9/4] at the grafting degree of0.5 mass%, while grafting of 13.5 mass% of PAA leads to a binding ratio of onevanadium atom per a chain of 12 PAA units (Fig. 6.4.).

Most likely that immobilization of transition metal acetylacetonates and carboxy-lates in nonaqueous media takes place according to ligand exchange mechanism,though the degree of participation of the grafted groups in those reactions is low.Similar to the cases discussed above, for the MXn with bulky substituents it is moredifficult to enter ligand exchange reactions (Table 6.6). Note for the comparison,that solubility of the carboxylates Cu.CnH2nC1COO/2 (n D 3, 7, 11, 17, and 29)

6.5 Formation of Macrocomplexes with Grafted Polycarboxylic Fragments 165

1.5

1.0

0.55

10

15

20

0 3 6 9 12Grafting degree of AA, wt.%

[V]b.104, g-at./g [COOH] / [V]b, mol / mol

1

2

Fig. 6.4 The interactions in the system of PE-gr-PAA-VO.OC2H3/3 at 333 K in heptane. (1) theamount of the bounded vanadium vs. grafting degree of acrylic acid; (2) the average number of AAunits per atom of the bounded vanadium

Table 6.6 The covalent binding of MXn with PE-gr-PAA in nonaqueoussolutions [62]

MXn

The content of boundedtransition metal, mmol/g

f , mol/molof [–COOH]0

TiC14 0.06 0.07VC14 0.14 0.18Ni.CH3COO/2 0.138 0.17Ni.C17H35COO/2 0.045 0.056NiL2(L – the residue of 0.024 0.030

naphtenic acidCo.CH3COO/ 0.067 0.085Co.C17H35COO/2 0.22 0.03Cr.CH3COO/3 0.15 0.19Cu.CH3COO/2 0.25 0.31Ni.acac/2 0.10 0.13Co.acac/2 0.32 0.40VO.acac/2 0.08 0.10Pd.acac/2 0.053 0.066

Note: It is grafted of 5.6 wt.% of PAA (0.8 mmol/g)

in low density PE at 363 K can increase by a few orders of magnitude if the poly-mer is preliminary oxidized, since the salt binding by ligand exchange occurs in thiscase [8].

It is well known that in selective solvents, block-copolymers of the PS-PAAtype (block-ionomers) exist as reversed micelles. In organic solvents block-copolymers are segregated into micro phases with spherical, cylindrical, andlamellar morphology. Metal ions are bound with carboxyl groups of the micellecore, due to formation of covalent or ionic bonds. Recently more complex block-copolymers have been developed for these aims, for example, diblock copolymer


Block-copolymers with isolatedmicrophases

~COOH

~COOH

~COO

~COO

Nanoreactor

Metal saltsM2+

Fig. 6.5 A principal scheme of the block-copolymer and its metallocomplex formation

0 2 4 6 8 100

200

400

600

800

1000

1200 % (Au)% (Ag)% (Pd)% (Cu)% (Fe)

C, mg / g

t, days

Fig. 6.6 The change of the degree of metal ions loading by block copolymer of(methyltetracyclododecene)400 (2-norbornene-5,6-dicarboxylic acid)50 vs. time. (C is loading ca-pacity, mg of metal/g of polymer)

(methyltetracyclododecene)400(2-norbornene-5,6-dicarboxylic acid)50 [63]. Ions ofAg, Au, Cu, Ni, Pb, Pd, Pt, and others form macrocomplex with units of the micellecore (Fig. 6.5). The loading of a metal can reach quite significant values, over 1 g/gof PAA block under the optimal conditions (Fig. 6.6).

6.6 Bimetallic Polycomplexes

Binding of different metal ions by polyacids is required for the solving of numerousproblems. Two variations of the preparation of these heterometallic polycomplexesare utilized. The first one is a simultaneous binding of different metals with poly-acids, and the second is the subsequent one. In the latter case, the macrocomplexobtained (with vacant carboxyl groups) is a specific ligand for the second (M0)metal binding. Often such products are called “complexes of complexes”. Thus,

6.6 Bimetallic Polycomplexes 167

for the polymers with grafted functional cover, it is relatively easy to choose con-ditions for an introduction of M0X0

m, which do not significantly affect the state ofalready immobilized MXn [64]. Methods of subsequent covalent or donor-acceptorinteraction of metal complexes, with the similar type functional groups of a poly-mer, are the most convenient for this. Such reactions were realized for polymers ofdifferent types, including carboxyl groups. For example, according to the followingscheme [65]:

CH2

CH2

CH

COOH

l

kMXnCH2 CH

COOH

l-kCH2 CH

COO MXn–1

k

pM'X'm

CH

COOH

l-k-pCH2 CH

COO MXn–1

kCH2 CH

COO M'X'm–1

p

M = Ni(II), Co(II), Cu(II); M' = Ti(IV), V(IV), V(V), Zr(IV)

It was established by special studies that there was no substitution of immobilizedMXn upon the introduction of M0X0

m. The degree of binding of M and M0, concen-tration ratios, the bond nature of a transition metal with polymer, and the structureof immobilized metal center obey the same peculiarities as in the case of immo-bilization of separate compounds, for example Ni.OCOCH3/2 or TiCl4. Althoughthese methods do not allow conducting an efficient control of distribution of tran-sition metals on a polymer carrier, the desired quantitative ratios between them canbe achieved by variation of the reaction conditions.

It can be supposed that in such polymer complexes M and M0 are spatially sep-arated and act as weakly interacting (or even disconnected) centers, although theyare bound one to another by polymer chain. However, magnetic behavior studiesof Ni(II) [or Co(II)]–V(IV) systems immobilized on PE-gr-PAA allowed to reveal[66], that even with the statistical distribution of transition metals, the system isnot completely disconnected (regarding the electron localization). Thus, the depen-dence 1/M Df .T / for the immobilized Ni(II) (eff D 3:77 �B at 298 K) has aslight curve at 110 K (Fig. 6.7) revealing a presence of weak spin–spin antiferro-magnetic interactions between the immobilized nickel ions. Layering the VCl4 onthis sample leads to a change in the magnetic behavior of the system: the dependence1/MDf .T / for the polymer bimetallic complexes strictly obeys the Curie–Waisslaw (T D 5 K), evidencing the disappearance of the interaction between Ni(II) ions.

Formation of ionic bridging complexes of the following type is possible in thecase of bimetallic complexes.

M

M′

O~C C~

O O

O→ ←

→ ←

The preparation of the LaMnO3 with utilization of PAA has been reported [67].Condensation of metal carboxylate with a metal salt or a mixture of metal salts inthe presence of a polymer can be used to this aim [68].


Fig. 6.7 The magneticproperties ofmetallocomplexesimmobilized into PE-gr-PAA:(1) PE-gr-PAACNiCl2 C VCl4; (2)PE-gr-PAA C NiCl2; (3)PE-gr-PAA C VCl4

100

100

200

300

400

200 300

20

40

60

80

100

T, K

3

1

2

(1 / χm)⋅10–2, g–1

(1 / χm)⋅10–2, g–1

For comparison, note that even in solutions containing cations of varied types,for example, Mo(V) and M(II) (M D Cu, Co, Fe, and Ni), in the case when oneof them or both have an asymmetric structure (i.e., when the enhanced electrondensity is localized on the periphery of an ion) associates are formed [69] by mostlyinvolving bridging ligands or (rarely) by charge transfer. The associates formed arepolynuclear heterometallic complexes. These reactions apparently also take place inmacrocomplexes, although they are complicated by an influence of a macrochain.Therefore, the immobilized systems are not electronically disconnected even uponbinding of heterometallic complexes with statistical distribution of MXn and M0X0

n.Cooperative type interactions are observed between paramagnetic metals.

6.7 Formation of Organic–Inorganic Composites

It has been demonstrated that such compounds as PdCl2 �2H2O and H2PtCl6 �6H2O,are capable of binding with miscellaneous type ligands comprised of organic–inorganic SiO2 hybrid with grafted copolymers of acrylic acid, and m- orp-divinylbenzene obtained by radical copolymerization in the presence of SiO2

[70]. Immobilization of AA on the surface of silicon plates is performed in a similarfashion, triggered by its free-radical polymerization, involving self-assemblingthin layers of azo-initiator, leading to formation of “brushes” on the surface(Scheme 6.2) [71]:

Layered ultra-thin films, based on the ionized polyacids and self-assemblingpolycations, are new materials obtained by stepwise adsorption of polymers on thesolid surfaces [72–74]. An interesting way to their formation consists of oxidative

6.7 Formation of Organic–Inorganic Composites 169

H2OO

OH

NEt3 toluene

immobilization

NSi

ON

CN CN

CH3

CH3

CH3

O

CH3

Cl

H3CSi–OH

H3C

H3C

SiOSi

Si

N

ON

CN CNCH3

CH3CH3

CH3

CH3

Opolymerization

O

CH3

CN

OO

Si

CH3

O OH

n

Scheme 6.2 Formation of polymer brushes onto the surface of silicon

MM

M MM

M

OHOH

HO

M MO

O

C

C

C

O

–O

–O

O

O

O

O

O

O

O

++

HO CO

C

C

O

O

O

–

–

O–

–

Fig. 6.8 A schematic view of crystal region of “inorganic core” and organic part of polymer metalcarboxylate complexes

dissolution of metals [75]. In such a case, metals (Cr, Mn, Fe, Co, Ni, Cu, Mn–Co) or their oxides are treated with a mixture of C3–C40 acids (including aromaticones) in the presence of polypropylene glycol and water. The reaction mixture isstirred at 75ıC and then water is removed at 150ıC. The high molecular weightmetal carboxylates formed are soluble in octane, cyclohexane, CCl4, benzene, THF,etc., and they very slowly (over several days) precipitate from these solvents. Theyconstitute “reverse micelles” (Fig. 6.8) with inorganic inner “core”, size of 3–8 nm,and an outer organic shell (carboxylates). The “molecular mass” of such micelles,


determined from their sedimentation rate, is estimated at 5� 104–1:5� 106. In theirturn, these particles may aggregate (especially in polar solvent that remove the“organic” shell) forming 10–30 nm size crystallites. Such carboxylates may beheterometallic as well. The products obtained are efficient catalysts of different pro-cesses. The catalysis takes place at the interface of a soluble layer and the “core”,and it resembles a homogeneous one. Most likely, this is a new kind of interfacialcatalysis. This type of complexes may be heterogenized from an organic solvent ona surface of another polymer.

Of special importance, is the problem of behavior of dispersions and solutionsof acrylic polymers containing carboxyl groups, present in dye composites used forprotection of metals and glues, and also for regulation of properties of differentdispersion systems, in particular, metal oxide dispergators employed in ceramicsmanufacturing. Metal polycarboxylates produce high reactivity ceramic oxide pow-ders, with large specific surface area [76]. For this purpose, PAA complexes ofdivalent, trivalent, and tetravalent metals are used [77]. This requires a detailed in-vestigation of adsorption and desorption processes, taking place on the surface ofparticles of dispersions upon their contact with carboxyl containing polymers [78].Thus, a kinetic study of copper(II) oxide [79] or ZnO [80] dissolution in polyacrylicacid (in the presence of hydrogen peroxide) showed that the rates of these reac-tions depend on the amount of adsorbed PAA. In its turn, PAA adsorption on copperincreases with its molecular mass. A decrease in the molecular mass results in in-creasing rate of copper dissolution, which is determined by the rate of PAA saltsdesorption [81].

A lot of attention is being paid to organic–inorganic hybrid materials, so-calledpolyelectrolyte-based cements, which were first synthesized in the late 1960s [82].The main area of their application is ceramics manufacturing, which includes theiremployment in dentistry and in the biomedical field, due to the good biocompatibil-ity and adhesion of these compounds. They are most often prepared by the reactionof PAA with metal oxides (mainly ZnO). The homogeneous material obtained con-tains up to 31.5% of zinc. A technological scheme for its manufacturing includesthe following steps (Fig. 6.9)[83].

Among other organic–inorganic hybrids, zinc polycarboxylates with calciumfluoroaluminosilicates forming high quality dental cements are worth mentioning[84–86]. Introduction of even small amounts of ionic additives based on trivalentmetals, such as Al.NO3/3 and Fe.NO3/3, to zinc polycarboxylate accelerates thecement setting reaction [38, 87].

Emulsion coatings (for example, see [88]) have received a relatively wide dis-semination. They are based on highly concentrated (about 35% by weight ofsolid residue) polyacrylate hydrosoles of acrylic acid-derived copolymers withM.NH3/2C

4 linking reagents (in particular, M D Cu or Zn [89]) which react readilywith carboxylate ions at relatively low temperatures (�120–150ıC). Metallopoly-mer coatings arising from fine emulsions (particle diameter 0.01–0:1 �m) possessenhanced physico-mechanic properties, they are water-resistant and their films areglossier. There are many more examples to list.

6.8 Binding of MXn by Natural Carboxyl Group Containing Polymers 171

Fig. 6.9 A schematicrepresentation of theprecipitate method forpreparing thezinc-acetate–PAA complex

PAA

Aqueous solution0.1 N

Zinc Salt

Aqueous solution0.1 N

Mixing

Filtering

Washing

Drying

Grinding

Characterization

Sodic Saltpreparation

PAA + NaOH(0.5N)

6.8 Binding of MXn by Natural Carboxyl Group ContainingPolymers

Distribution of metal ions in different physico-chemical phases causes definiteinfluence on their mobility and bioaccumulation. In this regard, multi-chargedmacromolecular ligands like humic acids or polysaccharides play a key role in lo-calization and accumulation of metal ions in natural objects.

Carboxymethyl cellulose (CMC) is the most often used among other naturalpolymers for the synthesis of metallopolymers. It is a homogeneous, fine, powder-like polymer that does not contain any groups but carboxyl, (up to 5 � 10�3 mol=g)capable of participating in ionic binding at moderate pH values (up to 10). Thus,60–80% of all deprotonated carboxyl groups of CMC reacts with Cu(II) [90], the si-multaneous coordination of one Cu ion with two carboxyl groups being impossiblebecause of purely steric reasons. Therefore, one of them forms a coordination bond,while the other participates in the binding by electrostatic interaction. Complexes ofCu(II), Ni(II), and Fe(II) with CMC-based membranes are less stable [91].


Unlike the Cu(II), molybdenum (VI) is adsorbed by CMC without excretion ofprotons with the formation of immobilized complex acid [90]:

COOH + H2MoO4 + H2O CO

OMo

OHO

OHHOH2O

The coordination number six, that is typical for protonated forms of Mo(IV),is achieved by water molecules or by the nearest carboxyl group of the polymer.Formation of coordination tridimentional networks takes place upon chemical in-teraction of functional groups of sodium methyl cellulose with a Cr3C salt [92].The linking is considered as a first rate reaction by the Cr3C concentration, the ef-fective rate constant of the chromium binding reaction being k D 0:025 h�1. Thecritical concentration of the gel formation is 0.3–0.5 mass%, depending on a molec-ular mass of the polymer, while the minimum concentration of the linking agent is0.012–0.014mol/L.

The efficiency of binding of Zn(II), Pb(II), Cu(II), and Cd(II) by pectin (poly-galacturonic acid, that has a similarity to cellulose chain structure, and carboxylgroups of which are partially esterified with methanol) has been studied. It wasshown [93] that each Zn(II) atom binds with two free carboxyl groups. Interest-ingly, the stability constant of the macrocomplex decreases with the increase of theesterification degree (between 0 and 90%) of the pectin. This reaction is consideredto be used for prevention of poisoning by toxic metal cations and their removal froman organism, while the dependence of the amounts of the bound Zn(II), upon the es-terification degree is suggested to regulate Zn(II) content in an organism. Similarfeatures are also observed upon binding of Ca2C ions [94]. It is also worth mention-ing the binding of humic compounds by aluminum hydroxocation nanoclusters onthe surface of kaolin [95].

Carboxymethyl dextran ether possess good binding properties toward Cu(II),Ni(II), and Co(II) [96], however, the degree of binding in this case is smaller thanfor PAA or PMAA.

In recent years metal binding properties of humic and fulvic acids are studiedintensively [97–99]. These acids are necessary and are the main links in soil formingprocesses, and create a specific “depot” of bioelements that regulates plant nutritionregime, depending on the environment conditions.

The problem of heavy metals complexation with these macroligands is impor-tant from the point of binding of their mobile forms. Finally, complexation of metalions with humic acids plays an important role in processes of migration and de-livery of biogenic metals into biological systems, in ore formation processes, forsolving ecological problems. Macromolecules of humic acids contain functionalgroups that are different by acidity (Chap. 1); each of those is a potential centerfor metal binding. Many kinetic features for complexation by humic acids are sim-ilar to those of their synthetic analogs: centers formed upon ionization of weaker

6.8 Binding of MXn by Natural Carboxyl Group Containing Polymers 173

Table 6.7 The formation constants of the coordination centers at the interactionof metal ions with humic acids [98]

Ionic strength ()0.01 0.1 1.0

Me2C lg K1 lg ˇ2 lg K1 lg ˇ2 lg K1 lg ˇ2

Cu2C 4.91 9.45 4.51 7.95 4.13 6.54Ni2C 4.82 9.05 4.23 7.45 3.70 6.44Zn2C 4.68 8.89 3.96 7.27 3.44 6.28Cu2C 4.45 8.45 3.75 6.85 3.34 –Cd2C 4.35 7.32 3.58 5.84 3.22 –Mn2C 4.07 7.15 3.35 5.79 – –

acidic groups participate in the reaction with the increase of the pH, an increase ofthe ionic strength causes enhancement of their acidic properties. However, this re-sults in an opposite effect on the stability of the metal complexes formed. Stabilityof the coordination centers increases with the decrease of ionic strength that is dueto polyelectrolyte properties of humic acids (Table 6.7).

Upon an increase of molecular mass of these acids, the stability of the complexesformed decreases slightly due to an increase in this case, of the portion of strongacidic groups in the whole pool of protonogenics. Additionally, at the pH > 4, whenthe macroligand is soluble, coordination centers of the ML2 type are formed, thecause of that being the optimal conformation required by stereochemistry of thecomplexes. In these conditions, macromolecules of humic acids exist as macroions,become flexible and adopt conformations that are energetically favorable for theformation of coordination units of the ML2 composition. Note, that well character-ized synthetic PAA is often used as a model for complex formation by humic acids[100–104].

Interaction of metal ions with natural polymers significantly affects redistribu-tion of microelements in geological deposits and soils. Formation of actinide (III)complexes with natural polyelectrolytes such as humic compounds, is consideredin the context of migration processes of actinides in natural waters and stabilityof their complexes formed [105, 106]. Broad thermodynamic studies of processesand mechanisms of complexation of their synthetic polyelectrolyte analogs, suchas PAA, polymaleic acid, –CH(COOH)n, PMAA, poly(’-hydroxyacrylic) acid, –.C.OH/.COOH/–CH2/n– and so on, are likely to be connected with just that.

A carboxyl group connected with a polymer chain is a unique and widespreadligand capable of efficiently binding practically any metal salts. During theirinteraction with polyacids, formation of a whole series of structures is possible.This depends upon experimental conditions, as well as structure and compositionof a polyligand. Polyacids are convenient objects for analysis of polymer effects,and finding peculiarities of complexation in macromolecular systems. Many aspectsof these problems, such as carboxyl containing polymers of condensation type,heteropolyacids (polyaminoacids, carboran containing, and so on), metallopolymerchelates (of the type [107]) and others, were not analyzed here. Considerationof biological activity of metal polyacrylates, for example, hemostatic properties


of the water soluble polymer feracryl (an iron containing salt of PAA), whichhemostatic action is already efficient in a form of 1% solution or dried gauze dressings[113], is worth a separate discussion. Another one out of numerous examples is anapplication of PAA and its Co(II), Zn(II) macrocomplexes as novel immunologicaladditives [114]. Although PAA itself increases formation of antibodies [108], itshigh toxicity (LD50 D 70 mg=kg) limits application of the substance. Applicationof macrosalts of these metals based on the copolymers of acrylic acid and N -vinylpyrrolidone confirmed [109] their immunomodulatory properties, they have lowtoxicityand lowinfluenceoncritically important functionsofanimalorganisms.Triplemetal salt of PAA of the composition, .CH2CH.COONa/n.CH2CH.COO/2:3Fe/m

.CH2CH/.COO/2Hg/p (nD 97–99 mol%, mD 0:04–0.06 mol% and pD 0:08–2.85 mol%), exhibits high antimicrobial activity (test cultures were strains of E.coli, Prot. vulgaris, Ps. aeruginosa, Staphylococus) [115]. This triple complexpossesses a strong bacteriostatic effect toward inhibition of those strains and a lowtoxicity value.

References

1. P. Molineux, Water-Soluble Synthetic Polymers:Properties and Behavior (CRC, Boca Raton,1984), p. 2)

2. E.A. Bekturov, Z.B. Bakauova, Synthetic Water-Soluble Polymers in Solution (Huethig andWepf, New York, 1986)

3. A. Caetano, M.N. De Pinho, E. Drioli, H. Muntau (eds.), Membrane Technology: Applicationto Industrial Wastewater Treatment (Kluwer Academic, Dodrecht, 1995)

4. I. Korus, M. Bodzek, K. Loska, Sep. Sci. Technol. 17, 111 (1999)5. K. Iwasa, I. Tasaki, R.C. Gibbons, Science 210, 338 (1980)6. I. Tasaki, P.M. Byrne, Biopolymers 34, 209 (1994)7. N. Plate, A. Litmanovich, O. Noah, Macromolecular Reactions: Pecularities, Theory and

Experimental Approaches (J. Wiley & Sons, New York 1995)8. A.D. Pomogailo, Polymer-Immobilized Metallocomplex Catalysts (Nauka, Moscow, 1988)9. E.F. Vainstein, The Study of the Peculiarities of the Complexation of Chain Molecules in

Diluted Solutions. Thesis . . . Doct. Chem. Sci. (ICP RAS, Moscow, 1981)10. G. Moravets, Macromolecules in Solutions (Mir, Moscow, 1967)11. V. Crascenzi, in Polyelectrolytes ed. by E. Segni (Reidel, Dodrechtm, 1974)12. A.D. Pomogailo, I.E. Uflyand, E.F. Vainshtein, Russ. Chem. Rev. 64, 857 (1995)13. J. Zurakowska-Orszagh, J. Skupinska, Polimery 30, 185 (1985)14. C.P. Nicolaides, N.J. Coville, J. Mol. Catal. 24, 375 (1984)15. M. Eige, Pure Appl. Chem. 6, 97 (1993)16. R.G. Wilkins, Kinetic and Mechanisms of Transition Metal Complexes (VCH, Weinheim,

1991)17. H.P. Gregor, M.J. Gold, M. D. Frederick, J. Polym. Sci. 23, 467 (1957)18. H.P. Gregor, L.B. Luttinger, E.M. Loebl, J. Phys. Chem. 59, 34 (1955)19. M. Mandel, J.C. Leyte: J. Polym. Sci. A 2, 2883 (1964)20. H. Morawetz, J. Polym. Sci. 17, 442 (1955)21. J.A. Marinsky, Coord. Chem. Rev. 19, 125 (1976)22. E.G. Kolawole, S.M. Mathieson, J. Polym. Sci. Polym. Chem. Ed. 15, 2291 (1977)23. C. Morlay, M. Cromer, O. Vittory, Water Res. 34, 455 (2000)24. E.G. Kolawole, S.M. Mathieson, J. Polym. Sci. Polym. Lett. Ed. 17, 573 (1979)25. E.G. Kolawole, J.Y. Olayemi, Macromolecules 14, 1050 (1981)

References 175

26. V.V. Saraev, I.A. Alsarsur, V.V. Annenkov, D.V. Tschipunov, Coord. Chem., 25, 919 (1999)27. J.A. Marinsky, W.M. Ansapach, J. Phys. Chem. 79, 439 (1975)28. L.Q. Yang, Z.M. Xie, Z.M. Li, J. Appl. Polym. Sci. 66, 2457 (1997)29. K.E. Branham, J.W. Mays, G.M. Gray, R.D. Sanner, G.E. Overturt, R. Cook, Appl.

Organomet. Chem. 11, 213 (1997)30. F. Fantinel, J. Rieger, F. Molnar, P. Hubler, Langmuir 20, 2539 (2004)31. C. De Stefano, et al., Talanta 61, 181 (2003)32. Z. Wojtczak, Rocz. Chem. 45, 237 (1971)33. R.D. Porasso, J.C. Benegas, N.A. Van den Hoop, J. Phys. Chem. B 103, 2361 (1999)34. J. (Alan) Xiao, A.T. Kan, M.B. Tomson, Langmuir 17, 4661 (2001)35. C. Fenn-Barrabass, A. Pohimeier, W. Knoche, H.D. Narres, M.J. Schwuger, Colloid Polym.

Sci. 276, 627 (1998)36. E.V. Anufrieva, Yu.Ya. Gotlib, Adv. Polym. Sci. 40, (1981)37. V.D. Pautov, E.V. Anufrieva, T.D. Anan’eva, V.B. Lushchik, T.N. Nekrasova, R.Yu. Smyslov,

Vysokomol. Soedin. A 48, 299 (2006)38. J.W. Nicholson, J. Appl. Polym. Sci. 70, 2353 (1998)39. V.F. Zolin, L.G. Koreneva, Rare-Earth Probe in Chemistry and Biology (Nauka, Moscow,

1980)40. Y. Okamoto, Y. Ueba, N.F. Dzhanibekov, E. Banks, Macromolecules 14, 17 (1981)41. Y. Takahashi, T. Kimura, Y. Kato, Y. Minai, Y. Makide, T. Tominaga, J. Radioanal. Nucl.

Chem. 239, 335 (1999)42. R. Roma, M. Morcellet, L. Sarraf, Mater. Lett. 59, 889 (2005)43. C.P. Nicolaides, N.J. Coville, J. Mol. Catal. 24, 375 (1984)44. C.P. Nicolaides, N.J. Coville, J. Organomet. Chem. 222, 285 (1981)45. G. Valentinin, G. Sbrana, G. Braca, J. Mol. Catal. 11, 383 (1981)46. E.A. Karakhanov, V.S. Pshe zhetskii, A.G. Dedov, Dokl. Akad. Nauk SSSR 275, 1098 (1984)47. C.E. Carraher Jr., S. Tsuji, W.A. Feld, Proceeding of Modification of Polymer Proceeding

Symposium (Las Vegas, NewYork, 1982)48. C.E. Carraher Jr., J.A. Schroeder, J. Polym. Sci. Polym. Lett. Ed. 13, 215 (1975)49. H. Nishide, N. ki, E. Tsuchida, Eur. Polym. J. 18, 799 (1982)50. R.I. Chernyshova, B.T. Voloshin, Ukr. Khim. Zh. 48, 210 (1982)51. F. Yamshita, T. Komatsu, T. Nakagawa, Bull. Chem. Soc. Jpn. 52, 30 (1979)52. A. Szilagyi, V. Izvekov, I. Vancso-Szmercsanyi, J. Polym. Sci. Polym. Chem. Ed. 18, 2803

(1980)53. A. Szilagyi, I. Vancso-Szmercsanyi, J. Polym. Sci. Polym. Chem. Ed. 21, 2225 (1983)54. M. Morcellet, J. Polym. Sci. Polym. Lett. Ed. 23, 99 (1985)55. K.M. Saldadze, V.D. Kopylova-Valova, Complexing Ionites (Complexites) (Khimiya,

Moscow, 1980)56. F.T. Shi, A.N. Astanina, G.V. Bystrov, Zh. Fiz. Khim. 58, 1818 (1984)57. V.A. Kabanov, V.I. Smetanyuk, Makromol. Chem. Suppl. 182, 121 (1981)58. E.A. Hegazi, N.B. Al-Assy, A.M. Rabie, I. Ishigaki, J. Okamoto, J. Polym. Sci. Polym. Chem.

Ed. 22, 597 (1984)59. N.M. El-Sawy, J. Appl.Polym. Sci. 67, 1449 (1998)60. A.D. Pomogailo, N.D. Golubeva, Kinetika i Kataliz. 26, 947 (1985)61. N.M. Bravaya, A.D. Pomogailo, E.F. Vainstein, Kinetika i Kataliz. 25, 1140 (1984)62. A.D. Pomogailo, A.P. Lisitskaya, D.A. Kritskaya, in Complex Organometallic Catalysts for

Polymerization of Olefins. Synthesis and Study of Catalytic Systems, vol. 8 (ICP AN SSSR,Chernogolovka, 1983), p. 78

63. R.T. Clay, R.E. Cohen, Supramol. Sci. 2, 183 (1995)64. D. Wohrle, A.D. Pomogailo, Metal Complexes and Metals in Macromolecules (Wiley-VCH,

2003)65. A.D. Pomogailo, Vysokomol. Soedin. A 50, 2090 (2008)66. A.D. Pomogailo, N.D. Golubeva, I.N. Ivleva, Kinetika i Kataliz. 25, 1145 (1984)67. H. Taguchi, D. Matsuda, M. Nagao, H. Sibahara, J. Mat. Sci. Lett. 12, 891 (1993)


68. M.M. Milanova, M. Kakihana, M. Arima, M. Yashima, M. Yoshimura, J. Alloys Compd. 242,6 (1996)

69. Z.A. Saprykova, N.D. Chichirova, Izv.Vuz’ov. Khimiya i khim. tekhnol. 25, 1039 (1982)70. X.-Y. Guo, H.-J. Zong, Y.-J. Li, Y.-Y. Jiang: Makromol. Chem. Rapid Commun. 5, 507 (1984)71. R. Konradi, J. Ruhe, Macromolecules. 37, 6954 (2004)72. P. Bertrand, A. Jonas, A. Laschewsky, R. Legras, Macromol. Rapid Commun. 21, 319 (2000)73. G. Decher, Science 277, 1232 (1997)74. G. Decher, J.B. Schlenoff, Multilayer Thin Films (Wiley-VCH, New York, 2003)75. C.U. Pittman Jr., E.H. Lewis, M. Habib, J. Macromol. Sci. A 15, 897, 915 (1981)76. M. Balastre, J.F. Argillier, C. Allain, A. Foissy, Colloids Surf. A 211, 145 (2002)77. R. Roma, L. Sarraf, M. Morcellet, Eur. Polym. J. 37, 1741 (2001)78. J. Cesarano, I.A. Askay, J. Am. Ceram. Soc. 71, 250, 1062 (1988)79. Y. Cohen, A.B. Metzner, Macromolecules 15, 1425 (1982)80. Y. Cohen: Macromolecules 21, 494 (1988)81. V.N. Kislenko, R.M. Verlinskaya, Kolloid. Zh. 63, 558, 613 (2001); 64, 447 (2002); Zh. Prikl.

Khim. 77, 1374 (2004)82. J.H. Adair, J.A. Casey, S. Venigalla (eds.), Characterization Techniques for the Solid-Solution

Interface (American Ceramic Society, 1994)83. M.E. Nicho, J.M Saniger, M.A. Ponce, A. Huanosta, V.M. CastaLno, J. Appl. Polym. Sci. 66,

861 (1997)84. S. Matsuya, T. Maeda, M. Ogata, J. Dent. Res. 75, 1920 (1996)85. E.A. Wasson, J.W. Nicholson, J. Dent. Res. 72, 481 (1993)86. J.W. Nicholson, J. Mater. Sci. Mater. Med. 4, 404 (1999)87. Y. Haga, S. Inone, M. Nakajima, R. Yosomiya, Mater. Chem. Phys. 19, 381 (1988)88. P.J. Moles, Polym. Paint Color J. 178, 154 (1988)89. L.Q. Yang, Z.M. Xie, Z.M. Li, J. Appl. Polym. Sci. 66, 2457 (1997)90. A.P. Fillipov, Teoret. Eksperim. Khimiya. 19, 463 (1983)91. C. Kamizawa, J. Appl. Polym. Sci. 22, 2867 (1978)92. V.V. Medvedeva, L.I. Myasnikova, Yu.D. Semchikov, L.Z. Rogovina, Vysokomol. Soedin. B

40, 492 (1998)93. A. Malovikova, R. Kohn, Collect. Czech. Chem. Commun. 48, 3154 (1983)94. D. Durand, C. Bertrand, A.H. Clark, A. Lips, Int. J. Biol. Macromol. 12, 14 (1990)95. Yu. Tarasevich, V.V. Lukyanova, G.M. Telbiz, Teoret. I Eksperim. Khimiya. 41, 45 (2005)96. L.I. Shevchenko, Z.A. Lugovaya, V.N. Tolmachev, Vysokomol. Soedin. A 27, 1993 (1985)97. J. Butfle, Complexation Reactions in Aquatic Systems (Ellis Horwood Ltd, Chichester, 1989)98. Sh. Jorobekova, Macro-Ligand Properties of Humic Acids (Ilim, Frunze, 1986)99. K. Kydralieva, Sh. Jorobekova, Metal Ions in Enzyme-Inhibitory Systems (Ilim, Bishkek,

2002)100. J. Buffle, Complexation Reactions in Aquatic Systems. An Analitical Approach (Ellis

Horwood, Chichester, 1988)101. R.F. Cleven, H.P. Van Leeuwen, Int. J. Environ. Anal. Chem. 27, 11 (1986)102. M. Esterban, H.G. De Jong, H.P. Van Leeuwen, Int. J. Environ. Anal. Chem. 38, 75 (1990)103. M.A. van Hoop, J.C. Benegas, Coll. Surf. A 170, 151 (2000)104. S.B. Clark, G.R. Choppin, in A Comparison of the Dissociation Kinetics of Rare Earth El-

ement Complexes with Synthetic Polyelectrolytes and Humic Acids in Humic and FulvicAcids: Isolation, Structure and Environmental Role. ASC Symposium Series, vol. 651, ed.by. J.C. Gaffney, N.A. Marley, S.B. Clark (ASC, Washington, DC, 1996), p. 207

105. G.R. Choppin, Radiochim. Acta 44/45, 23 (1988)106. J.I. Kim, P. Zeh, B. Delakowitz, Radiochim. Acta 58/59, 147 (1992)107. A.D. Pomogailo, I.E. Uflyand, Macromolecular Metal Chelates (Khimiya, Moscow, 1991)108. R.V. Petrov, R.M. Khaitov, R.I. Ataulkhanov, Immonogenetics and Artificial Antigents

(Moscow, 1983)109. F.N. Muratkhodzhaev, AS.A. Batyrbekov, A.P. Sirota, R.Z. Rafikov, Khim. Farm. Kh. 40

(1990)110. G.M. Barrow, Physical Chemistry for the Life Sciences (McGraw-Hill, New York, 1974)

References 177

111. M.M. Coleman, J.Y. Lee, P.C. Painter, Macromolecules 23, 2339 (1990)112. E.C. Kolawole, M.A. Bello, Eur. Polym. J. 16, 325 (1980)113. V.Z. Annenkov, A.E. Platonova, G.M. Kolonchuk, N.G. Dianova, V.B. Kazimirskaya,

V.M. Annenkova, G.S. Ugrumova, M.G. Voronkov, Khim. Farmaz. kh. 3, 322 (1982)114. P.A. Podkuiko, L.Ya. Tsarik, N.V. Zaitsev, Khim. Promyshl. 80, 30 (2003)115. E.L. Zhdanovich, O.A. Trifonova, T.I. Nikiforova, T.Ya. Pushechkina, V.M. Annenkova,

V.Z. Annenkova, M.G. Voronkov, Khim. Farm. Kh. 50 (1990)

Chapter 7Molecular and Structural Organizationof Metal-Containing (Co)Polymers

It is well known that properties of the polymeric materials based on (co)polymersdepend strongly on the sequence in which units of different nature are distributedthroughout a polymeric chain. Distinctions in the units’ distribution are displayedin the character of intermolecular interactions that finally causes the variety ofsupramolecular structures affecting the properties of the materials.

7.1 Ionic Aggregations and Multiplets

Many properties of the considered type metal-containing polymers are determinedby aggregation of ions, especially in the case of alkaline and alkaline earth metals,that allows to consider metal-containing polymers as typical representatives of aknown class of polymeric compounds – ionomers. Ionomers are polymers usu-ally containing carbon atoms in the main chain and including small amounts (upto 15 mol%) of acidic groups (carboxyl, sulfo-, phospho-, etc.) in the composition[1–3]. These groups can be the side units or can be included in the main poly-meric chain. Carboxylated ionomers are the most interesting from the practical pointof view. As it was shown [4], ionic associations, for example, in the sulfoiono-genic polymers, are much stronger than in their carboxylated analogues. It resultsin very high viscosity of the melts of sulfoionogenic polymers. Besides, residualsulfo-groups, are exposed, as a rule, to thermal destruction at their incomplete neu-tralization under the treatment at elevated temperatures. It is necessary to note, thatmost part of the commercially available ionomers is also obtained on the basis ofcopolymers of acrylic or methacrylic acids, for example, sodium or zinc salts ofcopolymers of ethylene with methacrylic acid (EMAA), etc.

7.1.1 Ionomers Synthesis

Basic obtaining methods of macromolecular metal carboxylates have been consid-ered in detail in the previous chapters. So, in this chapter we will stress attention onlyon those approaches which allow us to receive polymers of the required compositionand with the characteristics necessary for the development of specific properties of


179

180 7 Molecular and Structural Organization of Metal-Containing (Co)Polymers

ionomers. It is known that conventional methods of the ionomers synthesis are intwo-stages. In the first stage, the component, containing an ionogenic functionalgroup, is entered into a nonionic framework, after that these groups are subjected tofull or partial neutralization. In most cases, elastomers with relatively high molecu-lar weights are used as ionomeric precursors in the polymer-analogous reactions. Itresults in the obtaining of ionomers with high viscosity characteristics of their melts[5–7]. At the same time, use of the maleate-modified ethylene–propylene copoly-mers with molecular weights Mn 11;000�40;000 as precursors allows to obtainion-containing polymers with properties acceptable for processing [8, 9]. Acetatesalts or metals (hydro)oxides are usually used for neutralization of carboxyl groups[10–12]. An interesting method was offered for the synthesis of maleate-modifiedionomers. It includes ring opening reaction of the epoxidated three block-copolymer(styrene-butadiene-styrene (SBS)) using acidic potassium maleate [13]:

CH CH2 CH2CHCH2

O

CHCHnm m

nm mCH CH2 CH2CHCH2CHCH

OH O

CH

HOOC CH CH COOK

C O

HC COOK

Dimethylaniline (5 mass%) was used as a catalyst in this reaction. It is neces-sary to note that disubstituted potassium maleate was applied for the regulation ofmedium pH. It resulted in an increase of epoxidation degree up to the 40% potas-sium dimaleate/monomaleate ratio. Conversion of epoxy groups was more than 90%under optimal conditions.

It was discussed above that conventional approaches for obtaining the ion-containing polymers are multistage and laborious. So, copolymerization of unsat-urated acid salts (see Sect. 5.4) is the unique possibility of a single-stage synthesisof such polymers. Stable ionomeric emulsions on the basis of sodium or zinc acry-lates were received under their copolymerization with methyl methacrylate (MMA)and butylacrylate (BA) inpresence of dodecyl sulfonate (NaSO3.CH2/11CH3/ andK2S2O8 as the initiator at 60ıC [14, 15].

7.1.2 Morphology and Structure of Ionomers

Various models including such structures as multiplet-cluster [16, 17], core-shell[18, 19], cylinder [20], hard sphere [19], and others have been developed for the

7.1 Ionic Aggregations and Multiplets 181

description of the ionomers morphology. Despite their distinctions, it is consideredthat the main factor determining the peculiarities of structure and properties of theionomers is the formation of stable aggregates of ion pairs [16], which can com-pose multiplets or clusters in dependence on their concentration. The small compactaggregates of ion pairs are called multiplets, and aggregates formed from the sep-arate multiplets are called clusters. It is supposed [17] that there is an area withthe reduced mobility of polymeric chains around each multiplet. In case of highconcentrations of the charged groups in a polymeric matrix (>5–7%) these areasstart to overlap giving extended formations enriched with ions. The formations arecalled domains or clusters and they frequently show properties of an individualphase. Contribution of the separate aggregations is estimated by various physicaland chemical methods: small angle X-ray scattering (SAXS) [19, 21–23], studyingof dynamic, mechanical, rheological, or dielectric properties of metal-containingpolymers, Raman and IR-spectroscopy in the near range, and also EXAFS [24, 25]and rare-earth probe methods [26, 27]. Dominating formation of Cu(II)–Cu(II) pairin the copolymer of ethylene with methacrylic acid (5.4 mol%) was revealed byelectron paramagnetic resonance (EPR) method [28]. Isolated Cu(II) ions had onlyweak absorption at 300 mT (Fig. 7.1).

Absorption band at 254 cm�1 in the Raman-spectra of sodium polymethacrylate[29] was assigned to the vibrations of ions in the multiplets, and absorption band at166 cm�1 was assigned to the vibrations of ions in the clusters. It is explained by thefact that electrostatic interactions in big aggregates became more shielded and fre-quency of ionic vibrations is lower in comparison with the basic band of a separatecation or a multiplet. Intensity of the band correlates well with the concentration ofions in the clusters founded by the dielectric method (Fig. 7.2).

Similar regularities were also observed in case of copolymers of alkali metalsacrylates with styrene [30]. Ionic bands corresponding to the clusters appeared at

Fig. 7.1 EPR spectrum of copolymer of ethylene/methacrylic acid neutralized with 60% of Cu(II)


Fig. 7.2 The relativeintensity of adsorption bandat 254 cm�1 (1) and166 cm�1 (2) in the Ramanspectrum vs. the content ofmethacrylate sodium in itscopolymer with styrene

155 cm�1 for KC and NaC ions and at 95 cm�1 for CsC. The principal scheme ofsimilar aggregations can be represented as follows [31]:

++

++

++

++

++

++

++

+ +

++

+

++

It is necessary to note that state of the ionic aggregation depends on many factors,for example, on the cation nature, on the polymeric chain microstructure, on waysof obtaining the ionomer, etc. For example, metal-containing polymers obtained bysolid phase polymerization under the action of high pressures in combination withshearing deformations (HPC SD) show strong antiferromagnetic exchange betweenparamagnetic centers, both in homopolymers and in heterometallic copolymers onthe basis of Ni(II), Cu(II), and Ti(IV) acrylates (Table 7.1) [32, 33]. Antiferro-magnetic exchange is connected, most probably, with the interchain interactionsof the paramagnetic centers developed as a result of conformational changes inmacrochains under the action of HP C SD, i.e. the favorable conditions for theformation of multiplet and cluster domain structures are created. It is typical thatpolymers and copolymers obtained by liquid-phase polymerization do not show


Table 7.1 Magnetic properties of heterometal-containing copolymers

CopolymerMethodof synthesis

The contentof M1 (mol%)

�ef (B.M.) Antiferromagneticexchange295 K 80 K

(NiAcr2) .M1/–Cp2Ti(MAA)2

Radical, insolution

54 3:40 3:36 No exchange


Radical, insolution



Radical, insolution


Homopolymerof (NiAcr2)

Radical, insolution



Solid-phase(HP C SD)

42 4:30 3:75 Exchange



76 4:05 3:38 Exchange



91 3:73 3:36 Exchange

Homopolymerof (NiAcr2)


100 4:73 3:78 Exchange

(CuAcr2) .M1/–Cp2Ti(MAA)2


39 1:58 1:05 Strong exchange










Homopolymerof (CuAcr2)



antiferromagnetic exchange after HP C SD treatment. It confirms that structure ofthe complexes, combined into clusters with antiferromagnetic interaction, is formedat the stage of copolymers formation in afterflow conditions.

It was shown by WAXS and SAXS methods [22] that small ionic aggregates aremainly formed in the copolymer of zinc acrylate with styrene,1 [34, 35]. The ionicpeak 2‚ D 5:5ı appears at concentration of Zn acrylate equal to 7.02 mol% on aspectrum of wide angle X-ray scattering. Intensity of the ionic peak increases withan increase in metal acrylate content (Fig. 7.3).

Acrylates of alkali metals in their copolymers with styrene [30] form cluster ag-gregates with the sizes �70–100 A [23, 36], along with ion pairs and multipletsalready at concentrations 3.85 and 5.16 mol%. As a rule, temperature increase at

1 It is characteristic also for other Zn-containing ionomers. For example, the size of ionic aggre-gates is equal to 0.45 nm in all range of metal ion concentration in copolymers of ethylene withmethacrylic acid with neutralization degree 0.32–0.83. Ethylenic ionomers of copper and iron havethe same features.


Intensity

2 10 18 26 2q / deg

6

5

4

3

2

1

Fig. 7.3 WAXS spectra of zinc acrylate – styrene copolymer with a salt content of 3.67 (1),5.51 (2), 7.02 (3), 9.83(4), 17.59 (5), 19.48 mol% (6)

Table 7.2 SAXS dataa forthe ionomers based on zincacrylate and styrene atvarious contents of zincacrylate [22]

ZnAA (mol%) Q.mol=cm3/2 d (A) R (A)

7.02 0:109 � 10�3 17.3 3.79.83 0:147 � 10�3 17.7 3.817.59 0:211 � 10�2 15.8 3.719.48 0:534 � 10�2 19.8 4.0

aQ is the scattering invariant, d is the average distancebetween the domains, R is the radius of the ionic domain

SAXS studying, especially at higher than glass-transition temperature (Tg) of a poly-meric matrix temperature, results in an increase in the sizes and quantity of clusterparticles because of aggregation of free ion pairs and multiplets [22, 23]. But in thecase of the copolymer of zinc acrylate, perceptible change of the sizes of ionic ag-gregates and distance between them was not observed; only volume fraction of ionicaggregates was increased. It was testified by change of Q value (Table 7.2).


The character of the ionic associations is also determined by the nature of a sur-rounding polymeric matrix. Removal of the charged groups from the main chaincan favor the formation of ionic multiplets owing to the reduction of steric hin-drances. In its turn, influence of the formed multiplets on phase behavior of amacromolecule in such systems become weaker as it was shown in the case of thefunctionalizated liquid-crystalline ionomers containing carboxyl groups of acrylicacid, 3-acryloyloxypropionic acids, etc. [37]. If induction of a smectic phase inthe copolymers with acrylic acid occurs already at low metal ion concentrations(�2mol%), then an increase in distance between ionogenic groups and main poly-meric chain is revealed in the inability of an ionomer to form SA-phase. Tg of apolymeric matrix is one more tool for the effective control of the properties ofionomers. [38]. Poly(ethyl acrylate-co-itaconate) containing two ionic groups inone unit

CH2 CH

COOC2H5

CH2 C

COO-Na+

CH2

COO-Na+

x y

shows a high degree of cluster formation in comparison with a similar ionomerbased on the polystyrene characterized by the formation of several multiplets only.It is confirmed by the values of the relaxation module and the tangent of the angle ofmechanical and dielectric losses of the copolymers given [39]. Such behavior is con-nected with the noticeably low value of Tg of the polyethylacrylate matrix againstthe polystyrene system (�125ıC) [40]. According to the model [17], with an in-crease in ions content in a system, if the cluster’s size exceeds some fixed minimumsize, then ionomeric polymer shows the second glass-transition temperature con-nected with the combined effect of relaxation of a polymeric chain in a cluster areaand transfer of ionic groups in multiplets. According to the dynamics-mechanicalthermal analysis data [41], the ionomeric copolymers of polyethylacrylate andacrylic acid [poly(ethylacrylate)-co-acrylic acid (3.6–15.2 mol%)], neutralized byvarious cations, are characterized by two glass-transition temperatures. Lower glasspoints correspond to the Tg of the polyethylacrylate matrix while temperature trans-fers revealed in the high-temperature area are caused by cluster aggregates [42–44].From the functional dependence of the glass-transition temperature upon ion con-tent (Fig. 7.4) it is seen that Tg of the matrix linearly increases relatively slowly withan increase in ion concentration, and the cation type does not influence on Tg. Atthe same time, Tg of the clusters are differed among themselves depending on thecation nature and force of the ionic interactions, in particular on the q/a parameter,where q is an ion charge, a is a distance between cation and anion.

The ionomeric polymers feature (as a consequence of the ionic aggregations)is an increase in glass transition temperature that testifies the presence of an ionic


Fig. 7.4 The glass temperatures of poly(ethylacrylate) ionomers vs. the content of ions (a) and theparameter of cq/a (b)

Table 7.3 Glass-transition temperatures .Tg/ of copolymers of styrene (St) andacrylic acid (AA) and their Na-salts [48]

Tg (K) Temperature region of Tg forNa-containing ionomers, KCopolymera Copolymer Ionomer

PS 373 – –St–AA(3.9) 381 389 11St–AA(5.2) 384 394 15St–AA(6.4) 388 400 20St–AA(11.7) 395 410 32St–AA(14.1) 399 441 42aIn bracket the content of acrylic acid or sodium acrylate (mol%) is given.

cross-links in a polymeric matrix [45–48]. It is necessary to note, that Tg of theneutralized copolymers is appreciably higher than Tg of the acidic form of ionomers(Table 7.3).

It is seen that with an increase in content of carboxylated groups temperaturetransition range extends too. The character of the ions distribution in a polymericchain and their configuration influence the glass-transition temperature of the ob-tained ionomers. It was shown, for example, that Tg of the ionomeric copolymersSt–AA synthesized by emulsion method (for these copolymers mainly block struc-ture is characteristic [49]) is lower than Tg of the products of bulk polymerization[48]. Emulsion type copolymers have more long sequences of AA units due to bettersolubility of AA in water, while carboxyl groups of the copolymers obtained in bulkare distributed quite homogeneously in a polymeric chain. It results in the same se-quence of NaC ions and, accordingly, is homogenously distributed along all chainionic interactions, that is revealed in the chain mobility reduction and Tg increase.

The important characteristic of the ionomers obtained is the degree of neutraliza-tion of acid groups of an ionomeric precursor. The neutralization degree influences


Fig. 7.5 The experimentalneutralization degree vs. thegiven neutralization degreefor K- and Zn-ionomers. Thedoted line indicates the fullneutralization

100

K ionomers

Zn ionomers75

50

25

00 25 50

DNt (%)D

Nex

p (%

)75 100

both the microstructure and the final properties of the polymer formed. Thus, potas-sium acetate can neutralize only one of two carboxyl groups in the copolymerof maleic anhydride-gr-ethylene-co-propylene (MalAn-gr-EP) that results in theappearance of the plateau on the graph of dependence of the experimental neu-tralization degree (DNexp) vs. the specified neutralization degree (DNt) at 50% level(Fig. 7.5) [50].

DNexp value was calculated from the integral intensity of the asymmetric vibra-tion of a carbonyl group of the anhydride (CDO) at 1,785 cm�1 (A1785) usingintensity of rocking vibration of methylene group of ethylene/propylene chain at723 cm�1 (A723/ as the internal standard:

DNexp D

1 �

.A1785 =A723/ionomer

.A1785 =A723/precursor

!!� 100% (7.1)

Apparently, formation of the K-carboxylated group reduces considerably the activ-ity of the second carboxyl group of maleate unit against K acetate as a weak base.At the same time, practically full neutralization is observed in case of Zn2C cation.During neutralization, microphase division in an initial ionomer system caused bya polarity distinction between anhydride groups and non-polar ethylene-propylenechains is conserved, but its level depends greatly on the counterion nature. SAXSprofile for the K-ionomer is characterized by a sharp peak of dispersion while forthe Zn-containing ionomer this peak is appeared as a shoulder (Fig. 7.6).

Probably this distinction is connected with the features of coordination behaviorof Zn2C cations against dicarboxylated ionomer units. Spectroscopic investigations[51–54] testify the presence of the specific local ionic structures in the consid-ered type polymers. Proceeding from the known coordination tendencies for variouscations and from the analysis of symmetry of probable structures, various types of


50a b

40

30

Abs

olut

e in

tens

ity (

Å–3

)

Abs

olut

e in

tens

ity (

Å–3

)

20

K-100

Zn-25

Zn-100

Zn-50

K-50

K-25

MAn-g-EPM

MAn-g-EPM

10

00.00 0.05 0.10 0.15

q (Å–1) q (Å–1)

0.20 0.25

60

50

40

30

20

10

00.00 0.05 0.10 0.15 0.20 0.25

Fig. 7.6 SAXS profiles for maleic anhydride-gr-copolymer of ethylene/propylene and correspond-ing K- (a) and Zn-ionomers (b) with different neutralization degree

the local structures for alkaline, alkaline earth and zinc salts of copolymer of ethy-lene with methacrylic acid (4 mol%) were suggested [51]:

C

O

O

C

O

O

C

O

O

CO

O

CO

O

CO

OO

O

C

C

CO O

O OC

OO

OOC

(1) (2)

(3) (4)

In particular, multiplets of Li-and Na-ionomers of EMAA form octahedral struc-tures (3) and asymmetric stretching vibrations of COO� appears as a doublet1,568/1,547cm�1 (Na-ionomer) and 1,573/1,548cm�1 (Li-ionomer) in the IR-spectra according to the D3 symmetry group. On the contrary, analysis of the K- andCs-salts symmetry supposes the coordination numbers 8 (structures (4)) and onlyone IR-active frequency of asymmetric vibrations observed in the experimentalspectra (1,550 and 1;548 cm�1 for K- and Cs-ionomers, respectively). Change of amicrostructure was observed even at the obtaining of binary mixtures of ionomers,for example, on the basis of Na and Zn salts of EMAA of copolymer [55]. Ap-pearance of the new band of asymmetric vibration of COO� group at 1;569 cm�1

was observed in the IR-spectrum of the polymeric mixture (Fig. 7.7). This band was


EMAA-0.3Na

1540

cm

–1

1569

cm

–1

1585

cm

–1

EMAA-0.6Zn

1650 1600 1550

n /cm–1

1500

EMAA-0.3Na /EMAA-0.6Zn(75 / 25 w/w)

EMAA-0.3Na /EMAA-0.6Zn(50/50 w/w)

Fig. 7.7 IR spectra of binary mixture of the EMAA-0.3 Na and EMAA-0.6 Zn

referred to the bridging carboxylated group between sodium and zinc cations. Con-tribution of this bridging structure is especially observable at temperature increaseup to the area corresponding to the order–disorder transition in the ionic aggrega-tions. This transition yields the peak on the DSC curve in the field of 325 K, whilemelting of the crystal phase of PE occurs at 360 K. It is necessary to note, thatthe nature of the cluster transition is, as a whole, an important problem. It is a sub-ject of much research [56–59], as such properties of ionomers as viscoelasticity andrigidity undergo changes in this temperature area. It was shown that this transitionincludes two relaxation processes – the fast process (reversible) and the more slowprocess (irreversible) [60–62]. The more slow process means that formation of theionic crystallites during cooling of a melt occurs not at the melting point of a cluster,but it occurs gradually in time by keeping them at room temperature. As it was notedabove, increase of Tg of a polymeric matrix in ionomeric systems can be caused bythe aggregation of ions into small dense multiplets [63]. Tg is the linear function ofthe ion content in this area.

However, when Tg value is higher than some Tg value, fast increase of Tg isobserved which is connected with the beginning of cluster formation in ionomers[64]. Formation of the ionic clusters or domains in the Zn-containing ionomerPE-c-AA was observed atC50ıC [65] similar to the E-MAA copolymer [66]. Such


a transition was interpreted as “an ionic transition”, accompanying with the watermolecules elimination from the ionic clusters [67]. It results in loss of crystallinityof a polymeric matrix and in amorphization of the matrix, and it was confirmed byDSC-thermograms. At the same time, a new peak appears in this temperature area.This peak is connected with the vibrations of the ionic clusters and multiplets hav-ing various coordination structures [68] and testifying formation of a separate ionicphase.

Sizes of the forming domains can vary in a wide range depending on many fac-tors, including neutralization degree of carboxyl groups, coordination of a metal, alevel of microphase division and also nature and molecular weight of an ionomericmolecule. So, radii of domains for the maleate-modified copolymers of ethy-lene/propylene (Table 7.2) exceed considerably corresponding sizes for the othertypes of ionomers, for example, for the sodium or zinc neutralized copolymers ofethylene/methacrylic acid [34, 69]; or for the copolymers of acrylate of zinc andstyrene [22] (see Table 7.1). It is necessary to note, that SAXS parameters for thesystems under consideration (Table 7.4) are in good agreement with the modifiedYarusso-Cooper model [19]. According to this specified model, there are smalldispersive structures in a matrix along with the large domains in the MAn-g-EPionomers. It can be connected with the big distances between domains becauseof higher molecular weights, that increases probability of the fact that functionalgroups remain isolated in a matrix.

In some cases, such ion-containing polymers can be considered as nanocom-posites on a molecular level. For example, according to the transmission elec-tron microscopy data for the K-maleate ionomeric three block-copolymer styrene–butadiene–styrene, diameter of ionic domains is 3–8 nm (Fig. 7.8) [70].

Thus, the analysis shows that the dominating effect in the ionomers is the mi-crophase division into polar and non-polar domains due to the presence of ions. Itis revealed not only in bulk or in the swelling state of the ion-containing polymers,but also in a solution. Formation of the ion pairs and multiplets was founded ingels of sodium polymethacrylate in methanol [71]. Collapse of PAA neutralized bythe monovalent cations in methanol was detected by various methods [72]. Accord-

Table 7.4 SAXSa data for maleate-modified ethylene/propylenecopolymers [50]

The sample R (A) R1 (A) Vp (A3)

MAn-g-EP 17.3 44.9 3:9 � 106

K-ionomer (25) 26.1 63.3 5:3 � 106

K-ionomer (50) 23.4 56.1 3:3 � 106

K-ionomer (100) 24.8 58.2 3:4 � 106

Zn-ionomer (25) 18.0 47.9 2:7 � 106

Zn-ionomer (50) 18.8 50.3 3:8 � 106

Zn-ionomer (100) 16.9 49.6 3:3 � 106

a R is the radius of domains; R1 is the radius of the polymer layer with arestricted mobility; Vp is the average volume containing one scatteringparticle; in brackets the neutralization degrees are given.

7.2 Morphology and Topological Structure of Metal-Containing Polymers 191

Fig. 7.8 TEMmicrophotograph oflead-containing maleateionomers ofstyrene/butadiene/styrenetriblock copolymer

20nm

ing to the model [73, 74], ion pairs suffer collapse in a polymeric chain in solventswith low permittivity and associate then into multiplets, passing in “supercollapsedstate” or in an ionic mode. Ion pairs dissociate in polar solvents, and polyelectroliticmode predominates. The character of the interactions responsible for the particu-lar state, depends not only on the solvent, but also on the nature of counterions, onthe type of ionic groups in a polymer, and on the pH of medium. So, for exam-ple, in case of such divalent complexing cations as Cu2C or VO2C, counterions canbe associated into ionic groups in a polymeric chain even in such polar mediumsas water [75]. Investigations of the “metal cation-polymeric molecule” interactionsby the methods of molecular dynamics modeling [76, 77], show an essential roleof the entropic factors in such systems. Linkage of the short chains of polyacrylicacid with Ca2C-ions in an aqueous solution results in the formation of the stableconformation of a coil with a free surface energy equal to 18 kcal/mole at low con-centration of a polymer. At the same time local structures arise, in which Ca2C ionsform clusters with Ca2C � Ca2C distance equal to 4 A, and the most part of oxygenatoms are shared between calcium ions (Fig. 7.9). On the contrary, probability of acoil formation at high concentrations of PAA and Ca2C-ions is low because of thelocal rigidity caused by coordination of plenty of Ca2C by initially extended shortpolymeric chains, and interchain interactions became more preferable.

Various kinds of the “clusters of clusters” type aggregations are revealed also forthe organo-inorganic hybrid polymers containing true oxometallic cluster units (seeChap. 3), though the nature of their formation has not been understood yet [78].

7.2 Morphology and Topological Structure of Metal-ContainingPolymers

The structural organization of the considered type metal-containing (co)polymersis determined by a unique combination of properties of a metal-containing coor-dination polyhedron, by polyfunctional character of an initial monomeric salt and


Fig. 7.9 Model of PAA chain conformation in the presence of Ca2C ions

by a variety of the nature of inter- and intramolecular bonds of polymeric chains.A majority of the forming metal-containing copolymers has amorphous structurein spite of the regular, as it was discussed above, mainly syndiotactic structure anda developed system of intermolecular interactions, that, in the aggregate, createsfavorable conditions for the chains stacking and crystallizations of polymers. It isconnected, probably, with the large number of cross-linking bonds and ionic groups,that increases rigidity of the polymer’s chains and, consequently, complicates theirpacking.

7.2.1 Three-Dimensional Network Polymers

Even a minor change of the chemical composition or nature of the coordina-tion bonds of an initial monomeric salt can result in a change of a structure andproperties of the polymeric products. Visually it can be shown by the exampleof methacrylate derivatives of Ti(IV) alkoxides [79, 80]. As it was shown ear-lier, Ti.OR/3.OOCC.CH3/DCH2/ structure can be described by the equilibriumstructures I and II (RD i -Pro, 2-ethylhexyl), I, II, and III (t-Bu, t-Am), and IV(RDBu) [79]. The presence of a bidentate carboxylated bridge in a monomermolecule results in the formation of three-dimensional network polymer during its(co)polymerization:


Ti

RO

RO

RO

C

O O

Ti

C

O O

OR

OR

OR

Ti

RO

RO

RO

C

C

CH2H3C

CH2H3C

O O

Ti

C

C

O O

OR

OR

OR

Special research of the etherification reaction of titanium alkoxides with tetra-(copolymer of methacrylic acid, MAA, ethyl acrylate and ethyl methacrylate) andter-(copolymer of methacrylic acid, MAA, and butyl methacrylate)polymers hav-ing acidic functions were conducted [80]. It was shown that it is possible to controleffectively the formation of the cross-linked structures by such factors as molarTi/COOH ratio, nature of alkoxide groups, concentration, and composition of aninitial polymer. Instantaneous formation of a three-dimensional gel was observed atthe stoichiometric molar ratio of tetraalkoxide and acid function (Ti/COOHD 1) orat the molar deficiency of titanium alkoxide (Ti/COOH < 1). However, the charac-ter of a mixture changed at gradual increase in a molar fraction of titanium alkoxide(Ti/COOH > 1) – the gel became less dense and transformed into a stable solu-tion at fixed Ti/COOH value, which was accepted as threshold value. IR-spectraof the polymeric film obtained from this solution revealed bands �as(COO) and�s(COO) at 1,550 and 1;450 cm�1, that indicated a bidentate-chelate coordinationof carboxylated group with titanium atom (��D 100 SM�1). The role of the lig-and environment of the metal atom in the interchain space is also important. So, themore lengthy Ris in an alkyl chain, the below threshold value of Ti/COOH ratio is(Table 7.5) and the more easy the formation of chelated structures is.

A similar approach was successfully used for the prevention of a three-dimensional network formation during copolymerization of alkoxides of Ti(IV)methacrylate with MMA:

Ti

RO

RO

RO

C

C

CH2

O O

Ti

C

C

O O

OR

OR

OR

ROOR

OR

C

C

O O

Ti

ROOR

OR

C

C

O O

Ti

Ti(OR)4

Ti/COOH >–1

MMA

Initiator

ROOR

OR

CO O

Ti

ROOR

OR

CO O

Ti

H3C

CH2H3C

CH2H3C

CH2H3C


Table 7.5 Changeof Ti/COOH threshold valuein dependence on the natureof the alkoxide ligandTi(OR)4 [80]

Ti(OR)4 Threshold Ti/COOH

Ti(OEt)4 13/1Ti(OPr)4 12/1Ti.OiPr/4 17/1Ti(OBu)4 7/1Ti(OEH)4 3/1

Fig. 7.10 The temperaturedependencies of ©0 forcross-linked sodiumpolymethacrylate for aninitial concentration ofmethacrylic acid of 20 (1), 30(2) and 40% (3) (f D 1 kHz)

600

400

20 30 40T, °C

1

2

3

5040

60

80ε′ε′

Efficiency of cross-linking of the forming gel increased at rising of the ini-tial sodium methacrylate concentration in the presence of the cross-linking agent,N ,N -methylenebisacrylamide [81]. Dielectric properties of the polymeric systemare especially sensitive to the rearrangements of the mutual chains order. It wasconfirmed by a sharp increase of the real part of the dielectric constant ("0) ofdry cross-linked metal-containing polymers with an increase in an initial saltconcentration at the obtaining of the corresponding hydrogels (Fig. 7.10). Suchchange of "0 occurs because of the residual water; concentration and state of thewater are determined by the structure of a polymer network.

7.2.2 Interpenetrating Polymer Networks

The ability of the analyzed metal-containing copolymers to form spatially cross-linked structures is of crucial importance in the obtaining of the polymeric mixturesand alloys on their basis and gives vide opportunities for the modification of theproperties of polymers. As it is known, interpenetrating polymer networks (IPPN)are the combination of two cross-linked polymers, and synthesis and cross-linking,


at least, one of them is carried out in the presence of the second polymer. Metalpolyacrylates (for example, Zn [82, 83], Cr and Cu [83] or their monomeric salts)on the one hand, and vinyl monomers and (co)polymers on the other hand can bethe basic components of such systems. As a rule, an additional cross-linking agentas divinyl benzene (till 20–25 mol%) is used. Interpenetrating polymer networkscan be obtained on the basis of metal polyacrylates only, certainly, differed by thenature [84–87]. It is worth noting the following fact. If metal polyacrylates are usedas initial precursors in the polymer network formation, then in most cases they areconsidered as linear polymers soluble in benzene, DMFA, DMSO, dioxane [82, 83,85, 86]:

O O

Cr

OO

n

2

O O

Cu

OO

n

O O

Zn

OO

n

But there are no evidences of the proposed structures in the analyzed works ex-cept the fact of the polymers solubility, as it was discussed earlier, not all doublebonds can be involved in the polymerization process. The number of the residualunsaturated bonds depends on the monomeric salt nature, type, and conversion of thereaction and it is equal to 4–49% for the bifunctional carboxylates according to thedifferent estimations [88–90]. It is seen that the degree of unsaturation practicallyin all cases is less than 0.5. On the other hand, decrease in the residual unsaturatedbonds quantity can be explained, for example, by a formation of the intramolecularcycle structures of the following type:

CH CH2 CH~~CH2

Mn+

However, it is also impossible to exclude acts of interchain cyclization which willinevitably result in the cross-linked chains. So, in case of Co2C polyacrylate heatedduring 0.5 h at 100, 150, 200, and 250ıC significant decrease in intensity of thebands of the residual unsaturated bonds �.CDC/ (1,640 cm�1) in the IR-spectrumis observed, and this band practically disappears at 250ıC (Fig. 7.11) [91]. Suchprocesses can take place in the analyzed systems but their role during cross-linking,seemingly, is insignificant. It seems, for example, surprising that the swelling degree


Fig. 7.11 The fragments ofIR spectra of Co2C acrylate(1), its polymer (2), andpolymers after heattreatments during 0.5 h at 100(3), 150 (4), 200 (5) and250ıC (6)

1400 1600 1800

1

2

3

4

56

I

n, cm–1

Table 7.6 The effect of concentration of Zn(II) polyacrylate on theproperties of the IPPN [82]

[ZnPAA] �102 (mol/L) Yield (%) Swelling (%) NMc(g/mol)

14.49 6.3 41.4 3229.66 16.7 39.3 2944.78 20.8 37.0 2412.42 24.0 36.1 198

[Initiator] D 5:19 � 10�3 mol/L, [Styrene] D 1.38 mol/L, [MMA]D 1.44 mol/L, [DVB] D 0.83 mol/L

of a polymer network in DMFA and the average molecular weight of chains betweencross-links ( NMc) (Table 7.6) increase with an increase in concentration of Zn2Cpolyacrylate at the obtaining of IPPN on the basis of Zn2C polyacrylate [82].

At the same time, converse effects are observed when a monomeric salt is usedas an initial basic component of the IPPN. The cross-linking degree increases and,accordingly, NMc decreases with an increase in the monomeric salt concentration[92, 93].

A wide spectrum of physicochemical properties of polymeric mixtures is de-termined, first of all, by a compatibility of their components. It is possible toevaluate a degree of compatibility of two polymers by the glass-transition temper-atures (Tg/. Thus, as polyacrylate/polyacrylonitrile system (1:1) [85] has two closeTg (146 and 152ıC), that confirms sufficiently homogeneous distribution of twophases, each of which is enriched, seemingly, with one of the polymers – PAC-Asor PAN, accordingly. DSC-investigations confirm formation of a polymeric alloyfor the Bi polyacrylate/PAN mixture, which shows one, and higher, glass-transition


temperatures (281ıC). Intermolecular Van der Waals interactions and formation ofcomplexes at participation of CN-groups of PAN and metal atoms of polyacrylatespromote, probably, effective compatibility of the polymeric components. It is con-firmed by a shift of valence vibrations �.�C�N/ into the long-wave region in theIR-spectra of polymeric alloys (from 2,260 till 2,241 and 2;243 cm�1 for Bi poly-acrylate/PAN and As polyacrylate/PAN, accordingly). Degree of bond strength ofthe polymeric complexes can be estimated by the viscosity parameter kAB [94]:

.�A/B D.�A/

.�r/BŒ1C 2kAB .�B/ CB C � � � � (7.2)

where .�r/B is relative viscosity of the polymer B at concentration CB, .�A/, and(�B/ are internal viscosities of polymers A and B.

Similarly to the Huggins constants kA and kB, the kAB parameter depends onseveral types of the interactions, and hydrodynamical and thermodynamic interac-tions are determining. Thermodynamic contribution includes effects of the excludedvolume both intramolecular, resulting in an increase of a coil, and intermolecular,resulting in the compression of a coil. Thus, for the As polyacrylate (A) – Sb poly-acrylate (B) system, kAB values in such solvents as DMSO, DMFA, and dioxaneare 0.60, 0.42, and 0.26 accordingly, i.e., the strongest complex is formed in DMSOand the least strong complex is formed in dioxane in dependence on a permittivityof a solvent [93]. And, as a whole, these values indicate that interaction of As andSb polyacrylates between themselves is weak and has Van der Waals character.

It is known that salts of unsaturated carboxylic acids are frequently used as ac-tivating and reinforcing agents at vulcanization of rubbers. Cross-linking processesarising in such systems, result in the formation of the interpenetrating polymericnetworks with the improved physical-mechanical properties [95–97]. An especiallyeffective method is the method in which synthesis of a metal carboxylate and itspolymerization are carried out during formation of the IPPN in situ. One of theobtaining methods of the IPPN on the basis of nitrile-butadiene rubber (NBR) andZn(II), Al(III), Zr(IV) methacrylates [98] is the following. NBR and metal oxide aremixed in a Brabender mixer, then methacrylic acid and dicumyl peroxide are addedand the obtained composition is consolidated at 150ıC and 12 MPa during 30 min.According to another method, cross-linkage of NBR in the presence of metal oxideand peroxide (150ıC, 12 MPa, 30 min) is conducted at first. Then, obtained vulcan-izate was swelled in the MAA solution containing 0.5 mass% of AIBN with the sub-sequent heat treatment in a furnace at 150ıC during 8–10 h. Noticeable increase intensile strength (up to 17–19 MPa in comparison with NBR filled by metals oxides)and decrease of elongation (%) indicate formation of the IPPN in these systems.

The typical morphologic pattern of the analyzed polymer networks looks as acontinuous phase of the one component with characteristic inclusions of the secondcomponent (Fig. 7.12) of spheric [85], cellular [92] and other forms.


Fig. 7.12 Electron microscopy image of the polymer network on the base of Zn polyacrylate andcopolymer of styrene with MMA (magnification 790)

7.2.3 Hybrid Supramolecular Structures

It is known that binuclear metal carboxylates of the general formula M2.O2CR/4L2

have a characteristic structure of the lantern type (Fig. 7.13a). Formation of thehigh-symmetric two-dimensional structures (Fig. 7.13b) is observed in case of lin-ear dicarboxylated bridges, and an indefinite chain of homogeneous micropores(Fig. 7.13c) is created due to the interplane interactions in such systems.

Typical representatives of this class of compounds among unsaturated carboxy-lates are fumarates, trans–trans-muconates containing binuclear Mo2

4C [99–101],Rh2

4C [102] and Ru22C;3C [103] units. Synthesis of the considered type metals di-

carboxylates in the presence of polymers with one-dimensional chains results in aformation of supramolecular inclusion complexes [99, 100]:

Mo2(O2CCH3)4 Mo2(O2C-X-CO2)2 polymerCH3OH, Ar

X=CH=CH; CH=CH–CH=CH

polymer = HO CH2–CH2–O H; HO CH2–CH–O H

CH3

dicarboxylic acid,polymer

n n

The formed products are the noncovalently interacting ensembles of the guest–host type supramolecules (Fig. 7.14). In the complexes of Mo(II) fumarate withpolyesters [99], number of the included molecules of the polymer-guest depends onits molecular weight and reaches the saturation at the molecular weight more than


R

a b

c

8

R

R

R

Mo

Mo

Mo

Mo

Mo

Mo

MoMo

Mo

MoMo

Mo

Mo

Mo

Mo

Mo

Mo

Mo

Mo

Mo

Mo

Mo

MoMo

MoMo

LL MM

CC

C

C

Fig. 7.13 Microporous structure of coordination polymers of metal dicarboxylates: (a) lanternstructure; (b) two-dimensional infinite chain; (c) the formation of linear pores

Fig. 7.14 A schematic viewof the structure of Mo(II)dicarboxylate containingof poly (ethyleneglycole)in micropores

Polymer


M

N

M

M M

M

N

N N

N

N

N

N

N

N

M

N

N

self assembly

π – π stacking

= dicarboxylic ligand

linear chain complextwo-dimensional

layer and micropores

three-dimensional network [Zn

[Ni

(O2C

(O2C

CO2)(

CO2)(

N

N

3]

3]

·

·

N·(H2O)0·5

N·(H2O)2

)

)

Fig. 7.15 A scheme of the formation of a microporous structure for mononuclear metal dicar-boxylates

3,000, and it is equal to 4 ethylene glycol units per Mo2 unit in case of polyethyleneglycol. This value is twice less for polypropylene glycol, apparently, because of thegreater size of a monomer unit.

Mononuclear metal dicarboxylates show similar tendency in the formation ofmicroporous systems. In particular, peculiar stacks are formed because of – -interactions in the molecule of fumarate-pyridine complexes of Cu(II), Zn(II), Ni(II)due to the processes of self-assembly from one-dimensional regular linear chainsincluding metal atoms, connected by dicarboxylated ligands. It results in succes-sion in two- and three-dimensional structures with the great number of micropores(Fig. 7.15) [104].

This type of complexes are capable of absorbing significant amounts of reversibleabsorbing gases, for example, N2, Ar, O2, CH4, X. Thus, Zn(II) complex absorbsup to 10.6 moles of N2 per mole of a metal atom.

Intercalation of acrylate ions with the subsequent polymerization in situ inmolecules of layered double hydroxides (LDHs) as an inorganic host can be alsonoted among perspective synthetic strategies [105, 106]. Acrylate and polyacrylatenanocomposites on the basis of the replaced nickel hydroxide LDH(Ni0:7L0:3-(poly)acrylate) (LDFe, Co, Mn) were obtained according to this scheme [107,108].Monomeric and polymeric systems can be isolated in consistent stages of thesynthesis in case of Fe-containing intercalites, while for Co- and Mn-containingnanocomposites intercalation and polymerizations occur in one stage with the for-mation of polyacrylate composites immediately. Interlayer distances are equal to7.8–12.5 A (Fig. 7.16) in dependence on the synthesis conditions.

Liquid and organic crystals, micelles, two-layer lipids, etc. are often used ashighly organized mediums along with micro- and mesoporous compounds for


–O –O –O

O–

COO–

COO–

COO– COO–

COO– COO– COO–

COO– COO–

–OOC –OOC –OOC

COO– COO– COO– COO–

COO– COO– COO– COO–

O–O–

O O O

OOO

~13.4 Å

a b

c d

~12 Å ~7.8 Å

~12–12.5 Å

Fig. 7.16 Schematic view of intercalated nanocomposites: LDH(Ni0:7Fe0:3-acrylate) (a), twolayer LDH(Ni0:7M0:3-polyacrylate) (M D Fe, Co (b)), monolayer LDH(Ni0:7M0:3-polyacrylates)(M D Fe or Co (c) and Mn or Co (d)), The layered double hydroxides were obtained by solid-phase synthesis (b, c) and coprecipitation (d)

obtaining the supramolecular systems [109]. Thus, at mixture of the water-solublepoly(p-phenylenevinylene)dimethyl sulfide (PPPV) with amphiphilic acrylatemonomers [110, 111] of the following type

Na+ –OOC

O(CH2)11OOCCH=CH2

O(CH2)11OOCCH=CH2

O(CH2)11OOCCH=CH2

the inverted lyotropic liquid-crystal phase, in which PPPV pierces a hexagonal col-umn and orients parallel with its c-axis (Fig. 7.17), is formed.

Photopolymerization of an acrylate salt and subsequent heating of a cross-linkedmatrix results in the formation of hybrid PPPV with more intensive fluorescentproperties in comparison with the volumetric poly(p-phenylenevinylene). More-over, a new intensive band in the emission spectrum at 670 nm appears in case ofEu(III) [111] salt. It testifies interaction of metal cation with PPPV chains withpossible energy transport between components. Sizes of the inverted hexagonalphase depend on the metal nature and type of the metal–caroboxylate interaction[111, 112] and are also determined by length and structure of the aliphatic partof the amphiphilic mesogenic metal-containing monomer [113] p-styryl-(LC-1) orp-styryloxy-(LC-2) octadecanoates:


SMe2

H n

+ Cl–

hν

Δ

Δ

-nSMe2

-nHCln

Fig. 7.17 Scheme of stabilization of lyothropic liquid-crystalline phase by polymerization of anacrylate monomer

CO2– Na+ O

or

m + n + 3 = 18

CO2– Na+( )m ( )n ( )m ( )n

LC-1 LC-2

Interplanar distances of the hexagonal mesophase are the function of charge andsize of the metal ion (Table 7.7). Salts on the basis of trivalent lanthanide ions haveminimal sizes of unit cells in comparison with corresponding analogues of divalentions of transition metals that agrees also with IR-spectroscopy data on the nature ofthe carboxylated ion coordination. Stronger chelate coordination “carboxyl group-lanthanide ion” (�� D 96–97 cm�1) results in a decrease in general size of a headgroup of an amphiphilic molecule and provides more dense packing.

Metal ions of the greater size at identical charge value are more inclined to formlamellar or regular hexagonal structure. For example, potassium salts form a lamel-lae with interchannel distance (ICD) 38.9 A, while a well-defined inverted hexago-nal phase with ICD 41.9 A [112] is characteristic for Na-p-styryloctadecanoate. Incontrast to other salts, size of the mesophase formed by Cu-p-styryloctadecanoateis much less (Table 7.7) and X-ray diffraction data indicate formation of the ther-motropic columnar-hexagonal phase. It is probably connected with the peculiaritiesof binuclear structure which is characteristic, as it is known, for copper carboxy-lates. It is important to note that microstructure of the liquid-crystalline phase doesnot undergo essential changes during polymerization and cross-linking of the chains(Table 7.7).

A similar approach to the synthesis of highly organized systems was realized atthe obtaining of polymeric micelles. The rod-like form of the surphactante vinylbenzoate monomer


Table 7.7 Powder X-ray diffraction data for nanostructured polymers based on liquid-crystallinesalts of mesogenic metallomonomers [111, 112]

Compound LC-1a

After polymerizationCompound LC-2b

Monomer mixture After polymerization

d100 d110 d200 d100 d110 d200 ICDc d100 d110 d200 ICD

Metal ion (A) (A) Phased (A) Phase

NaC 34.5 20.2 17.5 36.7 21.1 18.3 42.1 RH 35.7 20.5 17.7 41.0 RHKC 38.2 19.5 13.0 38.8 L 38.2 19.2 13.0 38.6 LCa2C 30.9 18.1 15.7 36.1 RH 30.4 17.7 15.4 35.4 RHMg2C 28.9 16.9 14.6 33.6 RH 28.1 16.5 14.2 32.9 RHNi2C 35.8 20.8 18.2Co2C 35.6 20.3 17.7 27.7 15.9 13.8 31.9 RH 28.2 15.6 13.6 31.5 RHCd2C 35.0 20.6 18.0 30.0 17.4 15.3 34.9 RH 29.5 17.2 15.1 34.5 RHCu2C 23.0 13.3 11.5 26.7 CH 22.6 13.1 11.4 26.2 CHEu3C 30.2 17.6 15.7Ce3C 30.9 17.8 15.5aMonomer LC-1: H2O: 2-hydroxy-2-methylpropiophenone (20 wt% in xylene) – 85:10:5 (wt%)bMonomer LC-2: DVB: H2O: 2-hydroxy-2-methylpropiophenone (20 wt% in xylene) – 87:7:5:1(wt%)cICD is interchanell distancedPhase designations: RH is reverse hexagonal, L is lamellar, CH is columnar hexagonal

(CH2)11CH3NH3C

CH3

CH3+

COO

is stabilized during its radical polymerization, and the formed product has highthermal stability and does not show long dissociates in diluted solutions [114]. Pres-ence of the hydrophobic aliphatic groups in the copolymers of acrylic acid withN -dodecylacrylamide [115] or in the alternate copolymers of sodium maleate withalkylvinyl esters [116–121] of the following chemical constitution

CH2 CH

O

C12H25

CH

C CO O

ONa

CH

ONa n

promotes the formation of micelle-like aggregates from macromolecules of copoly-mers in aqueous mediums at critical concentration of micelle formation �2 �10�3 g=L. Quantities of the polymeric chains .m/ participating in the formationof micelle-like aggregates were estimated from average molecular weights (Mw) ofcopolymers of dodecylvinyl ester and sodium maleate (pC12M) differed in molec-ular weights and from average molecular weights (Mwm/ of micelle-like aggregateswhich were determined according to the data of sedimentation equilibrium measure-ment) [122]. The number of such polymeric chains is 16, 8, 2, and 1 as molecular


Table 7.8 Molecular-weight characteristics of copolymers of sodiummaleate with dodecylvinyl ether [122]

Polymer Mn � 10�3 Mw=Mn Mwm � 10�4 m

pC12M-1 3.3 1.4 7.6 16pC12M-2 6.0 1.5 8.0 8pC12M-3 18 1.9 6.7 2pC12M-4 89 3.0 19 0.7

masses of polymeric products increase that testifies significant tendency of pC12Mcopolymers to the intramolecular association (Table 7.8).

The ability of ion-containing polymers to self-organization increases in caseof their complexes, for example, with various types of surphactantes and aminesthat can result in the formation of complex types of hierarchical structures. Itwas established that interaction of diblock-copolymer of poly(ethyleneoxide)-poly(methacrylate of sodium) (PEO176-b-PMANa186) with surphactantes isattended by the formation of micelle-like aggregates – vesicles, in which insol-uble polyion–surphactante fragments are stabilized by polyethylene glycol chains(PEG) in an aqueous medium [123]. The diameter of the particles of such stoi-chiometric complexes changes within the limits from 85 up to 120 nm. In caseof inclusion complexes of, for example, ’-cyclodextrin (’-CD) with the abovementioned pC12M copolymers, reaction of cooperative linkage induces dissocia-tion of self-organizing micelle aggregates [121, 122]. Just competitive processes ofself-association in the considered type ion-containing polymers explain, seemingly,selective linkage of ’-CD since any interaction, for example, with ”- or “-CD forpC12M copolymers were not observed [122]. Self-organizing template complexesof “polyacrylic acid-cetyl trimethyl ammonium bromide” play a key role in mor-phogenesis of mesoporous silica gel surface in the presence of ions of alkali-earthmetals [124, 125]. Complexation of metal ions with carboxyl groups of a polyelec-trolitic chain causes, probably, bending of the polymeric chain and, finally, resultsin the formation of the curved micelle and generation of discoid or gyroid particlesin dependence on pH (Fig. 7.18).

The orienting influence of a “parent” polymeric chain and nonvalent interactionspromote the ordered polyelectrolitic complexes formation during matrix polymer-ization of Na methacrylate [126] or acrylate [127] in the presence of poly(allylamine) of hydrochloride as a template polymeric molecule. Kinetic effects of thereaction (high initial rate of polymerization and its dependence on a molar ratioof template units to a monomer) are in agreement with the growth of “daughter”chains on the so-called zip-mechanism. According to this mechanism, moleculesof the monomer are initially adsorbed on a template macromolecule and then theirpropagation occurs. In its turn, deviations from the ideal zip-mechanism can resultin the formation of a network-type structure (Fig. 7.19), for example, if the growingradical reacts with a monomer of another template chain, or chain growth occurswith involving of not adsorbed monomer molecules with the subsequent addition ofanother template chain. Reaction at this becomes diffusion- controlled and its rateaccordingly decreases.

7.3 Basic Types of Units Variability in Metal-Containing (Co)Polymers 205

Fig. 7.18 Scheme of the formation of micelle (a) and microphotographs of the hyroid particles oftemplate complexes PAA-STAB-Mg (b) and PAA-STAB-Sr (c) Scale bar at 1 �m

Thus, morphology and topological structure of the metal-containing polymersare much more complex than structures of traditional polymers, the structure is en-riched by the presence of metal ions in chains, their clusters and associates of higherorganization. Now the structure is more or less studied for alkaline, alkaline-earth,and transition metals, and its study has only been started for polyvalent metals.

7.3 Basic Types of Units Variability in Metal-Containing(Co)Polymers

Analyzing polymerization of the considered type metal-containing monomers, it isreasonable to start with the prerequisite that composition of the forming polymercorresponds to the composition of the initial monomer, and many experimental data


Adsorbed monomer unit

Growingradical

a

b

Templatechain

1

2

3

Fig. 7.19 Mechanism of template polymerization of sodium methacrylate in the presence ofpoly(allylamine hydrochloride) (a) and schematic view of the network structure of the resultingpolymer (b). (1) Formation of network nodes, (2) attachment of non-adsorbed monomer, (3) linearchain formation

confirm the given thesis as it is followed from the foregoing examples. However,units in which structure and geometry differ from the basic type units are alsoformed during formation of such polymers. It can result in breaking of chemi-cal and structural homogeneity (“defectiveness”) of a macromolecular chain, andreal macromolecules, in principle, cannot be represented as monotonously repeat-ing identical units, i.e., every possible type of anomalous additions (units variability)in them should be taken into account. These problems are very important for the de-termination of a connection between composition, structure, and properties of theproducts received by (co)polymerization of unsaturated metal carboxylates, and alsofrequently cause or limit various areas of products application.


Metal-containing polymers have two types of units variability. The first is charac-teristic for traditional high-molecular compounds (stereoregularity, presence of theresidual multiple bonds, structuring, and cyclization during polymerization, etc.)and the second – for metal-containing polymers [128, 129]. Types of units vari-ability of metal-containing polymers have principal importance for many areas oftheir use. They are partial elimination of metallogrouping and breaking of electronicstructure in the units (changes of the valence of a metal ion, its nuclearity and lig-and environment, extracoordination and changes of the form of the polyhedron ofmetal-containing complexes especially in case of polyvalent d -elements, characterof distribution of metallogrouping in a polymeric chain, etc. during formation ofmetal-containing polymers). We shall analyze some of them.

7.3.1 Units Variability, Caused by Elimination of MetallogroupingDuring Polymerization

It is one of the most important types of structural defectiveness in metallopolymericchains: unsuccessful attempts of polymerization of many MCM are connected withelimination [130] of a metal hydride and formation of “free-metal” polymers.

(y +z ) CH2 CH CH2 CHinitiation

COO

COO

CH CH + z MHXn –1 + zCO2

MXn / 2 MXn / 2

y z

Chemical transformations of unsaturated metal carboxylates proceeding inaqueous and polar solvents are accompanied by ionization and dissociation ofcarboxylates, that also can result in the formation of “free-metal” products. Es-pecially it concerns carboxylates of d -metals, which are strong electrolytes inwater. Salts of unsaturated carboxylic acids are practically completely dissoci-ated in aqueous or aqueous-organic mediums at pH > 7 (value of molar electricconductivity at infinite dilution is 0D 146 154 cm2Ohm�1mol�1) and otherparticles already act as monomers – acrylate- and methacrylate-ions in caseof salts of acrylic and methacrylic acids [131]. Aqueous solutions of Cu(II),Co(II), and Ni(II) acrylates are also average force electrolytes (dissociation de-gree is 0.52–0.53), concentration dependence of molar electric conductivity isdescribed well by the Kohlrausch equation [132]. Therefore, as it was shownin Sect. 5.2.2, polymerization of the investigated metal-containing monomers, iscarried out, as a rule, in the conditions excluding their dissociation, and metalcontent in the formed metallopolymers corresponds to the calculated value.Thermal polymerization of unsaturated metal carboxylates is also frequently ac-companied by elimination of metallogrouping. So, in case of copper(II) acrylate[133], relatively weak bond Cu–O breaks with the formation of CH2DCHCOO�radical which, interacting with a matrix, can be the channel, resulting in the


formation of “free-metal” units. Combination of thermal decomposition pro-cess with polymerization in solid phase occurs by a lot of transformations(190�240ıC). The final empirical composition of the polymers containing metallicfragments both carboxylated and not carboxylated (products of the elimina-tion of CO2, Cu(COO)2 groups with the formation of �CHDCH�CHDCH�,�CH2�CHDCH�CH2�, and others fragments) types can be expressed asŒCu.C6H4O4/p�x.C4H4/x.CuC6H6O4/q�y.C4H6/y.C6H8O4/j �z.C4H8/z�n.

7.3.2 Units Variability, Caused by Various Oxidation Rateof d-Metals

It is also one of the most widespread types of units variability. By analogy withmacromolecular complexes, it was possible to expect that homo- and copolymer-ization of metal-containing monomers will prevent or will slow down oxidativeor reducing processes with participation of metal ions. There are numerous ex-perimental data confirming that a polymeric matrix stabilizes low-valent metalscomplexes (for example [134], Pd(I)). Moreover, stability of Cu(I) condition dur-ing polymerization of copper(I) acrylate (including thermal polymerization) allowsto use [135] this method for the obtaining of coordination Cu(I) compounds. How-ever during polymerization of the monomers including ions of high-valent metals,reduction of the ions frequently occurs, for example: V5C ! V4C ! V3C,Fe3C ! Fe2C, Mo5C ! Mo4C, etc. The reasons for it can be very different.So, polymerization of Cu(II) acrylate as it was discussed earlier, is accompaniedby the reactions of intramolecular chain termination [136], it is promoted, proba-bly, by the relatively low values of standard potentials of reduction of copper ions(E0Cu.II/!Cu.I/ D 0:15 V).

Electron transport in such systems is realized by a complex way and accompa-nied by reduction of Cu2C up to CuC. Character of the electronic spectrum of thepolymeric product testifies that the electronic structure of copper ions has essentiallychanged during polymerization. The absorption band corresponding to the excita-tion of d–d-transfer in electron shell of Cu2C ion is observed at 14;800 cm�1 inthe electronic spectrum of the initial monomer of Cu(II) acrylate (Fig. 7.20). In thespectrum of the polymerization product, this band completely disappears but bandat 28;000 cm�1 instead appears. At least, for those ions which have kept the va-lence, such change of a spectrum (hypsochromic shift) can be described (see [137])as change of the symmetry in the structure of their nearest environment which is asquare pyramid from oxygen atoms in an initial complex.

Oxygen atoms of carboxyl groups are at the base of the pyramid, and oxygenatom of the coordinated alcohol molecule are at the top of the pyramid. Set of thereceived data including IR spectroscopy ones (Fig. 7.21) allows to assume that unitsof the polymeric chain are dimers of one- and divalent copper with the preservationof the bridge structure:


1.6

900700500400350300250

1

2

200

1.2

0.8

0.4

050 42 34 26 18

ν . 103, cm–1

ν, nmD 2.0

Fig. 7.20 Absorption electron spectra of copper(II) acrylate (1) and the product of its polymeri-zation (2)

H2C H2CHC HC

COO

CH2CHCH2CH

COO

CH=CH2

CO O

CO O

CH2CH

CO O

CH2CH

OOC

CH2=CH

Cu1+ Cu1+

Cu2+ Cu2+

7.3.3 Anomalies in Metal-Containing Polymers ChainsCaused by a Variety of Chemical Linkageof a Metal with a Polymerized Ligand

This type of units variability can be most visually shown by the example of met-als salts with unsaturated carboxylic acids. As was discussed in Chap. 4, structuralfunctions of a carboxylated group RCOO� are very varied. It can act as mono-(I),


100

1

2

80

60

Tra

nsm

issi

on, %

40

20

020 18 16 14 12 10 8 6

ν . 10–2, cm–14

Fig. 7.21 IR spectra of copper(II) acrylate (1) and of the polymer product (2)

bi-(II, III), three- (IV) or tetradentate (V) ligand at interaction with a metal ion evenon the condition that the multiple bond does not participate in complexing.

The spectroscopic data of metals acrylates testify mainly ionic character of aM–O bond with a degree of covalence 0.13 0.16, and, as it was noted above,some reduction of the orbital contribution to the metal–ligand ¢-bond in the macro-molecule composition were observed. It is interesting, that an increase in the lengthof metal–ligand bonds and reduction of the degree of their covalence [138] occur attransferring from acrylate complexes to their saturated analogues (acetates).

It was shown by IR- and dielectric spectroscopy [139–142] that distortion ofbridge groups geometry occurs during polymerization of metal acrylates under theaction of internal stresses in the structure of the forming network. Sometimes it canresultin destruction of the bridge bonds. For example, the new absorption band at�1;700 cm�1 appears in the IR-spectrum of the polymeric product at polymeriza-tion of polynuclear Cr(III) oxoacrylate [143]. It is connected, most likely, with theformation of monodentate carboxylated groups (Fig. 7.22). Overlapping of the fre-quencies corresponded to the bridge and nonbridge bidentate carboxylated groups,as it is typical for the polymeric Fe(III) oxoacrylate, were not observed [144].

7.3.4 Extracoordination as One of the Types of Anomalies(Spatial and Electronic Structure of a Polyhedron)

Coordination unsaturation of the central atom, promoting comparatively easy pass-ing of a lot of the side processes, is one of the reasons of relatively low stabilityof some metal-containing monomers and polymers on their basis. Both speciallyentered substances and molecules of a solvent, most often – water, can act as an addi-tional ligand. Not all chemically bonded with a metal atom ligands are removed from


100

80

60

1

2

40

Tra

nsm

issi

on, %

20

022 18 14 10 ν.10–2, cm–1

Fig. 7.22 IR spectra of chromium(III) acrylate (1) and of the polymer product (2)

the product after polymerization, it also is a source of units variability in polymers.As a whole, as it was discussed above, geometry of the metal atom does not un-dergo essential changes during polymerization, but reorganizations in the structureof the nearest environment of a metal atom can sometimes take place. For example,at thermal solid-phase polymerization in the Fe3C maleate molecule with the lo-cal symmetry of Fe–O bonds close to cubic, reorganization of the structure towardsmore asymmetric one occurs [145]. Higher asymmetry of the nearest environmentand spin–lattice relaxation are characteristic also for Fe(III) ions in the polymericoxoacrylate [144]. Bathochromic shift of one of the bands (up to 21;500 cm�1) inthe electronic spectrum of the Fe(III) polyacrylate corresponding to the forbiddend–d -transitions in the electronic shell of Fe(III) (Fig. 7.23) is observed.

7.3.5 Unsaturation of Metal-Containing Polymersand Their Structurization

These phenomena can be caused by various reasons: involving not all multiplebonds into polymerization, peculiarities of the restriction reactions and chain trans-fer reactions, etc. Ability of the metal-containing copolymers [146] based on Co orNi acrylates with styrene to dissolve in polar solvents up to the fixed contents ofacrylate units testifies passing of the process mainly by one of the multiple bonds; itrelates also to their graft polymerization [147]. Part of the unreacted double bondsin (co)polymers of transition metal diacrylates [88, 90, 146] with traditional vinylmonomers increases in the series Zn2C .35%/ < Co2C (39%) < Ni2C (49%), whichcorrelates with the ability of these acrylates to homopolymerization (unsaturation isequal to 50% in those hypothetical cases when only one acrylate group reacts). Itis necessary to note that presence of the residual double bonds and opportunity oftheir add-polymerization can be used for the obtaining of the network polymers with


250

3600

0

2800

0

2400

021

500

200

1.5

1.0

0.5

50 40 30 20ν.10–3, cm–1

D

2

1

300 350 500 λ, nm

Fig. 7.23 Absorption electron spectra of iron(III) oxoacrylate (1) and of the polymer product (2)

high strength and plasticity at high softening points. Such properties of the metal-containing polymers obtained will be analyzed in the subsequent chapters.

Thus, various types of units variability in metal-containing polymers chains canarise during polymerization of MCM. Some of them make the essential contribu-tion to their structure and serve as specific levers of control of composition andproperties of the metal-containing polymers formed, others have only hypotheticalcharacter. The analysis of units variability carried out in metal-containing polymerchains can cause the impression of multiplicity of the side processes concomitantpolymerization of MCM. It can seemproblematic to achieve uniqueness of the poly-merization products of such monomers connected just with structural homogeneityof the macrocomplexes formed, which were noted in the introduction. Actually it isnot so. Many of the considered side reactions can be prevented or their role can beessentially reduced. There are many approaches for this purpose, most convenientof them – low-temperature polymerization processes including polymerization withuse of the irradiation. This approach allows to carry out polymerization in a widetemperature range (including and post-radiation variant) and at any phase states ofa monomer. Even if it is impossible to exclude units variability, it is almost alwayspossible to take it into account (sometimes quantitatively).

According to the IUPAC [148] nomenclature, metal-containing polymeric chainscan be referred to the regular macromolecules at low contents of the units withanomalous structure. Structures of these macromolecules include mainly recurrenceof the identical constituent units connected with each other in the same way. Irregu-lar macromolecules are formed at the considerable contribution of units variability.Structure of the irregular macromolecules included the constituent units connectedwith each other along the chain not in the same way.

References 213

Thus, the given data testify that the range of the molecular organization of theconsidered type metal-containing polymers is rather wide: from linear polymers upto di- and three-dimensional network and supramolecular structures. The structure-chemical control at all levels of the metal-containing copolymers organizations(molecular, topological, and the supramolecular) allows to obtain polymers witha complex of valuable properties, that is especially important from the standpoint ofthe modern tendencies of creation of the new generation materials.

References

1. A. Eisenberg, M. King, Ion Containing Polymers. Physical properties and structure.(Academic press, New York, 1977)

2. A. Eisenberg (ed.), Ions in polymers (American Chemical Society, Washington, DC, 1980)3. M.R. Tant, K.A. Mauritz, G.L. Wilkes (eds.), Ionomers: Synthesis, Structure, Properties and

Applications (Chapman & Hall, London, 19974. R.D. Landberg, H.S. Makowski, in Ions in Polymers, ed. by A. Eisenberg (American Chemical

Society, Washington, DC, 1980)5. S. Bargoda, G.L. Wilkes, J.P. Kennedy, Polym. Eng. Sci. 26, 662 (1986)6. S. Datta, S.K. De, E.G. Kontos, J.M. Wefer, J. Appl. Polym. Sci. 61, 177 (1996)7. T. Kurian, D. Khastgir, P.P. De, D.K. Tripathy, S.K. De, Rubber World, 41 (1995)8. M.E.L. Wouters, J.G.P. Goossens, F.L. Binsbergen, Macromolecules 35, 208 (2002)9. M.E.L. Wouters, V.M. Litvinov, F.L. Binsbergen, J.G.P. Goossens, Macromolecules 36, 1147

(2003)10. S. Datta, S.K. De, E.G. Kontos, J.M. Weper, J. Appl. Polym. Sci. 61, 177 (1996)11. S.K. Ghosh, P.P. De, D. Khastgir, S.K. De, Macromol. Rapid Commun. 20, 205 (1999)12. S.K. Ghosh, P.P. De, D. Khastgir, S.K. De, J. Appl. Polym. Sci. 77, 816 (2000)13. H.-Q. Xie, W.-G. Yu, D. Xie, D.-T. Tian, J. Macromol. Sci. Part A. Pure Appl. Chem. 44, 849

(2007)14. Y.M. Wang, Y. Cao, H.Q. Xie, J.S. Guo, Polym. Emul. Commun. 15, 15 (1995)15. Y. Wang, H. Xie, Y. Cao, J. Guo, Polymer J. 29, 875 (1997)16. A. Eisenberg, Macromolecules 3, 147 (1970)17. A. Eisenberg, B. Hird, R.B. Moore, Macromolecules 23, 4098 (1990)18. W.J. MacKnight, W.P. Taggart, R.S. Stein, J. Polym. Sci. Polym. Symp. 45, 113 (1974)19. D.J. Yarusso, S.L. Cooper, Macromolecules 16, 1871 (1983)20. S. Kumar, M. Pineri, J. Polym. Sci. Polym. Phys. Ed. 24, 1767 (1986)21. D.J. Yarusso, S.L. Cooper, Polymer 26, 371 (1985)22. C. Slusarczyk, A. Wlochowicz, A. Gronowski, Z. Wojtczak, Polymer 29, 1581 (1988)23. K. Suchocka-Galas, C. Slusarczyk, A. Wlochowicz, Eur. Polym. J. 36, 2167, 2175 (2000)24. D.J. Yarusso, Y.S. Ding, H.K. Pan, S.L. Cooper, J. Polym. Sci.: Polym. Phys. Ed. 22, 2073

(1984)25. K.V. Farrell, B.P. Grady, Macromolecules 33, 7122 (2000)26. Y. Okamoto, Y. Ueba, N.F. Dzhanobekov, E. Banks, Macromolecules 14, 17 (1981)27. V.A. Smirnov, G.A. Sukhodolskii, O.E. Filipova, A.P. Khokhlov, Zh. Fiz. Khim. 72, 710

(1998)28. J. Yamauchi, S. Yano, E. Hirasawa, Makromol. Chem. Rapid Commun. 10, 109 (1989)29. A. Neppel, J.C. Butler, A. J. Eisenberg, Polym. Sci.: Polym. Phys. Ed. 17, 2145 (1979)30. K. Suchocka-Galas, Eur. Polym. J. 34, 127 (1998)31. S. Bagrodia, R. Pisipati, G.L. Wilkes, J. Appl. Polym. Sci. 29, 3065 (1984)32. G.I. Dzhardimalieva, V.A. Zhorin, I.N. Ivleva, A.D. Pomogailo, N.S. Enikolopyan, Dokl.

Akad. Nauk SSSR 287, 654 (1986)


33. G.I. Dzhardimalieva, Metal-Containing Monomers of -type Based on Elements of the FirstTransition Series And Their Polymerization Transformations. (PhD Thesis, Moscow 1987)

34. Y. Tsujita, M. Yasuda, M. Takei, T. Kinoshita, A. Takizawa, H. Yoshimizu, Macromolecules34, 222 (2001)

35. N.M. Benetatos, K.I. Winey, J. Polym. Sci. Part B. Polym. Phys. 43, 3549 (2005)36. K. Suchocka-Galas, Eur. Polym. J. 25, 1291 (1989)37. E.B. Barmatov, D.A. Pebalk, M.B. Barmatova, V.P. Shibaev, Vysokomol. Soedin. A 43, 53

(2001)38. D. Duchesne, A. Eisenberg, Can. J. Chem. 68, 1228 (1990)39. S.-H. Kim, J.-S. Kim, Macromolecules 36, 1870 (2003)40. J.-S. Kim, Y.H. Nah, S.-S. Jarng, Polymer 42, 5567 (2001)41. S.-H. Kim, J.-S. Kim, Macromolecules 36, 2382 (2003)42. J.-S. Kim, G. Wu, A. Eisenberg, Macromolecules 27, 814 (1994)43. T. Kanamoto, I. Hatsua, S. Shirai, K. Tanaka, Rept. Prog. Polym. Phys. Jap. 16, 245 (1973)44. K. Suchocka-Galas, J. Appl. Polym. Sci. 96, 268 (2005)45. A. Eisenberg, M. Navratil, Macromolecules 7, 90 (1974)46. H. Matsumura, A. Eisenberg, J. Polym. Sci. Polym. Phys. Ed. 14, 773 (1976)47. W.J. MacKnight, T.R. Earnest, J. Polym. Sci. Macromol. Rev. 16, 41 (1981)48. K. Suchocka-Galas, J. Appl. Polym. Sci. 89, 55 (2003)49. C.W. Brown, G.A. Taylor, J. Appl. Polym. Sci. 13, 629 (1969)50. M.A.J. van der Mee, R.M.A. I’Abee, G. Portale, J.G.P. Goosens, M. Van Duin, Macro-

molecules 41, 5493 (2008)51. B.A. Brozoski, M.M. Coleman, P.C. Painter, Macromolecules 17, 230 (1984)52. M.M. Coleman, J.Y. Lee, P.C. Painter, Macromolecules 23, 2339 (1990)53. P.C. Painter, B.A. Brozoski, M.M. Coleman, J. Polym. Sci. Polym. Phys. Ed. 20, 1069 (1982)54. A. Brozoski, M.M. Coleman, P.C. Painter, Polym. Sci. Polym. Phys. Ed. 21, 301 (1983)55. S. Kutsumizu, H. Hara, H. Tachino, K. Shimabayashi, S. Yano, Macromolecules 32, 6340

(1999)56. R.J. Goddard, B.P. Grady, S.L. Cooper, Macromolecules 27, 1710 (1994)57. K. Tadano, E. Hirasawa, S. Yano, Macromolecules 22, 226 (1989)58. E. Hirasawa, Y. Yamamoto, K. Tadano, S. Yano, Macromolecules 22, 2776 (1989)59. S. Kutsumizu, N. Nagano, H. Tachino, E. Hirasawa, S. Yano, Macromolecules 25, 6929

(1992)60. S. Kutsumizu, H. Hara, H. Tachino, K. Shimabayashi, S. Yano, Macrmolecules 32, 6340

(1999)61. A.K. Ray, J. Therm. Anal. 46, 1527 (1996)62. Y. Gao, N.R. Choudhury, N. Dutta, R. Shanks, R. Weiss, J. Therm. Anal. Calorim. 73, 361

(2003)63. A. Eisenberg, Contemp. Top Polym. Sci. 3, 231 (1979)64. A. Eisenberg, J.-S. Kim, Introduction to Ionomers (Wiley-Interscience Publication,

New York, 1999)65. S. Mohanty, K. Vijavan, N.R. Neelkantan, G. B. Mando, Polym. Eng. Sci. 37, 1395 (1997)66. W. MacKnight, L.W. McKenna, B.E. Read, J. Appl. Phys. 38, 4208 (1967)67. R.J. Goddard, B.P. Grady, S.L. Cooper, Macromolecules 27, 1710 (1994)68. S. Kutsumizu, N. Nagoa, H. Tadano, E. Hirasawa, S. Yano, Macromolecules 25, 6829 (1992)69. S. Kutsumizu, H. Tagawa, Y. Muroga, S. Yano, Macromolecules 33, 3818 (2000)70. H.-Q. Xie, W.-G. Yu, D. Xie, D.-T. Tian, J. Macromol. Sci. Part A Pure Appl. Chem. 44, 849

(2007)71. O.E. Philipova, N.L. Sitnikova, G.B. Demidovich, A.R. Khokhlov, Macromolecules 29, 4642

(1996)72. N.Th. Klooster, M. van der Touw, F., M. Mandel, Macromolecules 17, 2070, 2078, 2087

(1984)73. A.R. Khokhlov, E. Yu Ktamarenko, Macromolecules 29, 681 (1996)74. O.E. Philipova, D. Hourdet, R. Audebert, A.R. Khokhlov, Macromolecules 30, 8278 (1997)75. K. Kruczala, S. Schlick, J. Phys. Chem. B 103, 1934 (1999)

References 215

76. F. Molnar, J. Rieger, Langmuir 21, 786 (2005)77. R.E. Bulo, D. Donadio, A. Laio, F. Molnar, J. Rieger, M. Parrinello, Macromolecules 40,

3437 (2007)78. V. Torma, N. Husing, H. Peterlik, U. Schubert, C.R. Chimie 7, 495 (2004)79. M. Camail, M. Humbert, A. Margaillan, A. Riondel, J.L. Vernet, Polymer 39, 6525 (1998)80. M. Camail, M. Humbert, A. Margaillan, J.L. Vernet. Polymer 39, 6533 (1998)81. I.A. Malyshkina, N.D. Gavrilova, E.E. Makhaeva, Vysokomol. Soedin. B 41, 368 (1999)82. G.S. Mishra, A.K. Srivastava, Polymer Int. 42, 281 (1997)83. N. Gupta, A.K. Srivastava, Macromolecules 28, 827 (1995)84. N. Gupta, A.K. Srivastava, Acta Polymerica 47(5), 224 (1996)85. P. Moham, A.K. Srivastava, Indian J. Chem. Technol. 6, 219 (1999)86. M. Kamal, A.K. Srivastava, J. Macromol. Sci. Pure Appl. Chem. 37, 1627 (2000)87. M. Kamal, A.K. Srivastava, Polym.Plast. Technol. Eng. 40, 293 (2001)88. A. Gronowski, Z. Wojtczak, Acta Polymerica 36, 59 (1985)89. G.I. Dzhardimalieva, A.D. Pomogailo, Izv. Akad. Nauk SSSR Ser. Khim., 352 (1991)90. T.A. Bykova, B.V. Lebedev, V.N. Larina, L. Ya. Tsvetkova, G.I. Dzhardimalieva,

A.S. Rozenberg, A.D. Pomogailo, Vysokomol. Soedin. A. 45, 921 (2003)91. G.I. Dzhardimalieva, A.D. Pomogailo, S.P. Davtyan, V.I. Ponomarev, Izv. Akad. Nauk SSSR

Ser. Khim., 1531 (1988)92. M. Kamal, A.K. Srivastava, React. Funct. Polym. 49, 55 (2001)93. M. Kamal, A. Dwivedi, J. Macromol. Sci. Part A Pure Appl. Chem. 45, 548 (2008)94. N. Tewari, A.K. Sriwastava, Angew. Makromol. Chem. 170, 127 (1985)95. Z. Peng, X. Liang, Y. Zhang, Y. Zhang, J. Appl. Polym. Sci. 84, 1339 (2002)96. X. Yuan, Y. Zhang, Z. Peng, Y. Zhang, J. Appl. Polym. Sci. 84, 1403 (2002)97. M. Ronald, US Pat. 4,720,526 (1988)98. A.B. Samui, V.G. Dalvi, L. Chandrasekhar, M. Patri, B.C. Chakraborty, J. Appl. Polym. Sci.

99, 2542 (2006)99. S. Takamaizawa, M. Furihata, S. Takeda, K. Yamaguchi, W. Mori, Macromolecules 33, 6222

(2000)100. S. Takamaizawa, M. Furihata, S. Takeda, K. Yamaguchi, W. Mori, Polym. Adv. Technol. 11,

840 (2000)101. S. Takamaizawa, W. Mori, M. Furihata, S. Takeda, K. Yamaguchi, Inorg. Chim. Acta. 283,

268 (1998)102. F.A. Cotton, L.M. Daniels, C. Lin, C.A. Murillo, S-Y. Yu, J. Chem. Soc. Dalton Trans. 502

(2001)103. S. Takamaizawa, T. Ohmura, K. Yamaguchi, W. Mori, Mol. Cryst. Liq. Cryst. 342, 199 (2000)104. T. Ohmura, W. Mori, M. Hasegawa, T. Takei, T. Ikeda, E. Hasegawa, Bull. Chem. Soc. Jpn.

76, 1387 (2003)105. M. Tanaka, I.Y. Park, K. Kuroda, C. Kato, Bull. Chem. Soc. Jpn: 62, 3442 (1989)106. S. Rey, J. Merida-Robles, K.S. Han, L. Guerlou-Demourgues, C. Delmas, E. Duguet, Polym.

Int. 48, 277 (1999)107. C. Vaysse, L. Guerlou-Demourgues, E. Duguet, C. Delmas, Inorg. Chem. 42, 4559 (2003)108. C. Vaysse, L. Guerlou-Demourgues, C. Delmas, E. Duguet, Macromolecules 37, 45 (2004)109. K. Tajima, T. Aida, Chem. Commun 2399 (2000)110. R.C. Smith, W.M. Fischer, D.L. Gin, J. Am. Chem. Soc. 119, 4092 (1997)111. H. Deng, D.L. Gin, R.C. Smith, J. Am. Chem. Soc. 120, 3522 (1998)112. D.H. Gray, D.L. Gin, Chem. Mater. 10, 1827 (1998)113. M.A. Reppy, D.H. Gray, B.A. Pindzola, J.L. Smithers, D.L. Gin, J. Am. Chem. Soc. 123, 363

(2001)114. S.R. Kline, Langmuir 15, 2726 (1999)115. I. Tomatsu, A. Hashidzume, A. Harada, Macromolecules 38, 5223 (2005)116. U.P. Strauss, B.W. Barbieri, Macromolecules 15, 1347 (1982)117. B.W. Barbieri, U.P. Strauss, Macromolecules 18, 411 (1985)118. J. L. Hsu, U.P. Strauss, J. Phys. Chem. 91, 6238 (1987)119. W. Binana-Limbele, R. Zana, Macromolecules 20, 1331 (1987)


120. W. Binana-Limbele, R. Zana, Macromolecules 23, 2731 (1990)121. D. Taura, A. Hashidzume, A. Harada, Macromol. Rapid Commun. 28, 2306 (2007)122. D. Taura, A. Hashidzume, Y. Okumura, A. Harada, Macromolecules 41, 3640 (2008)123. A.V. Kabanov, T.K. Bronich, V.A. Kabanov, K. Yu, A. Eisenberg, J. Am. Chem. Soc. 120,

9941 (1998)124. C.C. Pantazis, A.P. Katsoulidis, P.J. Pomonis, Chem. Mater. 18, 149 (2006)125. C.C. Pantazin, P.N. Trikalitis, P.J. Pomonis, M.J. Hudson, J. Microporous Mesoporous Mater.

66, 37 (2003)126. G. Polacco, M.G. Cascone, L. Petarca, G. Maltinti, C. Cristallini, N. Barbani, L. Lazzeri,

Polymer Int. 41, 443 (1996)127. P. Cerrai, G.D. Guerra, S. Maltinti, M. Tricoli, P. Giusti, L. Petarca, G. Polacco, Macromol.

Rapid Commun. 15, 983 (1994)128. G.I. Dzhardimalieva, A.D. Pomogailo, Variability of Mixed-Unit Chains in Metal-Containing

Polymers. Chapter in Book: Metal-Containing Polymeric Materials, ed. by C.U. Pittman Jr.,et al. (Plenum Press, New York, 1996), pp. 63–79

129. A.D. Pomogailo, G.I. Dzhardimalieva, Izv. Akad. Nauk. SSSR Ser. Khim., 2403 (1998)130. C.U. Pittman Jr., in Organometallic Reactions, vol. 6, ed. by E.I. Becker, M. Tsutsui

(New York, 1977), p. 1131. V.A. Kabanov, D.A. Topchiev, Polymerization of Ionizing Monomers (Nauka, Moscow, 1975)132. B.S. Selenova, G.I. Dzhardimalieva, E..B. Baishiganov, O.N. Efimov, A.D. Pomogailo, Izv.

Akad. Nauk. SSSR Ser. Khim., 1025 (1989)133. E.I. Aleksandrova, G.I. Dzhardimalieva, A.S. Rozenberg, A.D. Pomogailo, Izv. Akad. Nauk.

SSSR Ser. Khim., 308 (1993)134. L.B. Krentsel, A.D. Litmanovich, N.A. Plate, E.I. Karpeiskaya, L.F. Godunova, E.I.

Klabunovskii, Vysokomol. Soedin. A. 34, 10 (1992)135. G.I. Dzhardimalieva, I.N. Ivleva, E.N. Frolov, A.D. Pomogailo, Izv. Akad. Nauk. SSSR Ser.

Khim., 1145 (1998)136. G.I. Dzhardimalieva, A.D. Pomogailo, S.P. Davtyan, V.I. Ponomarev, Izv. Akad. Nauk. SSSR

Ser. Khim., 1531 (1988)137. F. Cotton, J. Wilkinson, Modern Inorganic Chemistry (Mir, Moscow, 1969)138. R.C. Mehrotra, R. Bohra, Metal Carboxylates (Academic Press, London, New York, 1983)139. B.S. Selenova, G.I. Dzhardimalieva, M.V. Tsykalova, S.V. Kurmaz, V.P. Roshchupkin, I. Ya.

Levitin, A.D. Pomogailo, M.E. Vol’pin, Izv. Akad. Nauk. SSSR Ser. Khim., 500 (1993)140. I.A. Chernov, G.I. Dzhardimalieva, G.F. Novikov, A.S. Rozenberg, A.D. Pomogailo, in Struc-

ture and Dynamics of Molecular Systems, vol. 2 (Yalchik, 2002), pp. 258–261141. G.F. Novikov, I.A. Chernov, G.I. Dzhardimalieva, A.D. Pomogailo, Condensation Medium

and Interphases 7, 239 (2005)142. I.A. Chernov, G.F. Novikov, G.I. Dzhardimalieva, A.D. Pomogailo, Vysokomol. Soedin.

A 49, 428 (2007)143. M. Shulga, I.V. Chernushevich, G.I. Dzhardimalieva, O.S. Roshchupkin, A.F. Dodonov, A.D.

Pomogaylo, Math. AN. Ser. Chem 6, 1047–1051 (1994)144. Yu.M. Shulga, O.S. Roshchupkina, G.I. Dzhardimalieva, I.V. Chernushevich, A.F. Dodonov,

Y.V. Baldokhin, P.Ya. Kolotyrkin, A.S. Rozenberg, A.D. Pomogailo, Izv. Akad. Nauk SSSR,Ser. Khim., 1739 (1993)

145. A.T. Shuvaev, A.S. Rozenberg, G.I. Dzhardimalieva, N.P. Ivleva, V.G. Vlasenko,T.I. Nedoseikina, T.A. Lubeznova, I.E. Uflyand, A.D. Pomogailo, Izv. Akad. Nauk SSSR,Ser. Khim., 1505 (1998)

146. G.I. Dzhardimalieva, A.D. Pomogailo, Izv. Akad. Nauk SSSR, Ser. Khim., 352 (1991)147. V.S. Savostyanov, A.D. Pomogailo, D.A. Krytskaya, A.N. Ponomarev, Izv. Akad. Nauk SSSR,

Ser. Khim. 45; 353 (1986)148. A.D. Jenkins, P. Kratochvil, R.F.T. Stepo, U.W. Suter, Pure Appl. Chem. 68, 2287 (1996)

Chapter 8Properties and Basic Fields of Applicationof Metal-Containing Polymers

The properties of metal-containing (co)polymers and also of traditional polymersmodified by them are determined in many respects by the potential ability of metalions to form ionic and coordination cross-links, to realize electron transitions inmetal atoms under both electric field effect and high-energy radiations, to showcohesive and adhesion interactions.

8.1 Improvement of the Polymeric Materials Properties Basedon Cross-Linking Action of Monomeric and Polymeric Salts

As was shown above, various cross-linking mechanisms with participation of theconsidered compounds are possible: (co)polymerization of monomeric salts; addi-tional interchain coordination interaction of a metal ion with an electron-saturatedheteroatom; add-polymerization of residual double bonds, and, lastly, by means ofthe formation of aggregates and multiplets in ionomers molecules as nodes of aphysical network. Cross-linking at photopolymerization of metal acrylates in a gela-tine matrix (R, R0 – gelatine macromolecules) occurs by the addition mechanism toa double bond [1, 2]:

~R–NH–CH2–CH2–CO–O–M–O–CO–CH2–CH2–NH–R ~

~R'–OH + CH2=CH–CO–O–M–O–CO–CH=CH2 +HO–R'~

~R'–O–CH2–CH2–CO–O–M–O–CO–CH2–CH2–O–R' ~

~R–NH2 + CH2=CH–CO–O–M–O–CO–CH=CH2 + H2N–R~

Substantial increase in thermo- and heat-resistance of metal-containing carboxy-lated (co)polymers is observed at their cross-linking in comparison with “free-metal” analogues. The value of the destruction temperature .Td/ of metal-containingmacromolecules frequently is 300–400ıC and higher. So, Td for Li and Na [3] poly-methacrylates are equal to 457 and 491ıC accordingly. Decomposition of Co(II),Ni(II) and Zn(II) polyacrylates occurs at the same high temperatures (Table 8.1) [4].

Mass losses up to 210ıC are caused by the liberation of methanol (solvent atpolymerization), occluded in polymers. The second endothermic peak refers already


217

218 8 Properties and Basic Fields of Application of Metal-Containing Polymers

Tab

le8.

1T

heth

erm

alde

com

posi

tion

ofm

etal

poly

acry

late

sin

nitr

ogen

atm

osph

ere

[4]

Poly

mer

Proc

ess

DT

Ga

TG

AD

TA

Peak

ofte

mpe

ratu

re.ı

C/

Tem

pera

ture

regi

on(ı

C)

Mas

slo

ss(%

)

The

tota

lm

ass

loss

inth

ere

gion

25–5

00

ıC

Peak

ofte

mpe

ratu

re.ı

C)

Tem

pera

ture

regi

on(ı

C)

Zn(

II)

poly

acry

late

Res

idue

ofso

lven

t(M

eOH

)re

leas

e84

<210

14.5

51.5

90<

210

Dec

ompo

siti

on418

360–

460

35.0

416

397–

440

Co(

II)

poly

acry

late

Res

idue

ofso

lven

t(M

eOH

)re

leas

e96

<210

18.0

60.5

110

<210

Dec

ompo

siti

on410

370–

480

39.4

413

403–

450

Ni(

II)

poly

acry

late

Res

idue

ofso

lven

t(M

eOH

)re

leas

e93

<210

22.0

65.5

102

<210

Dec

ompo

siti

on368

300–

415

40.0

374

360–

415

a The

diff

eren

tial

ther

mal

anal

ysis

8.1 Improvement of the Polymeric Materials Properties 219

to more significant decomposition of polymeric salts. As a whole, thermo-resistanceof polyacrylates changes in a series Zn2C > Co2C > Ni2C > Cu2Cdepending uponthe metal’s nature. Cross-linking action of metal carboxylates as di- and polyvinylmonomers is revealed distinctly also at the obtaining of copolymers on their ba-sis. So, the initial temperature of terpolymers [5] destruction, corresponding to the5% mass loss in the nitrogen atmosphere, increased from 350 up to 380ıC withan increase in the content of lead methacrylate from 5 up to 25 mass% in ter-polymers composition, and the glass transition temperature is essentially changedtoo (from 126 up to 148ıC). Addition of only 0.5 mol% of the cluster monomerZr6O4.OH/4.CH2DCHC.CH3/OCO/12 to the copolymerized system resulted inthe 50ıC increase in the polystyrene Td, and in the 110ıC increase in the PMMATd [6, 7]. Cross-linking effects in the cluster-containing copolymers of this typeare even more intensified under add-polymerization of their residual double bondsas it took place at post-heat treatment of the copolymers of the cluster methacry-late [Mn12O12.CH2DC.CH3/COO/16.H2O/4] with MMA [8]. It is typical thatobtained copolymers are differed by composition homogeneity; it is confirmed bythe only Tg temperature according to the DSC data. The Tg temperature is a functionof the cluster units content in the copolymer.

As was discussed earlier, the role of ionic cross-links is rather essential for theion-containing copolymers obtained at low degrees of conversion, when the cross-linking processes caused by covalent bonds can be neglected. It is confirmed by anincrease in the copolymers Tg with an increase in concentration of an ion-containingcomponent (Table 8.2) [9, 10].

Table 8.2 The glass temperatures of copolymers of metal acrylates with styrene [9]

Metal acrylate

The content of metalacrylate in copolymer(wt%) Tg .ıC/

Tg .ıC/

(calculated)Tg of metalpolyacrylate (ıC)

– 0 87Zn 7:05 103 102

10:41 107 10913:07 114 11422:77 134 13329:84 146 146

100 423Co 1:76 94 91

4:20 97 958:53 103 104

11:26 109 10917:06 115 119

100 368Ni 2:04 95 92

3:80 98 966:01 102 100

11:29 109 11113:74 114 116

100 410


As can be seen, a good agreement between experimental and theoreticallycalculated by the (8.1) Tg values was established [11]:

Tg D�.wATgA CKwBTgB/=.wA CKwB/

�C qwAwB; (8.1)

where TgA and TgB are glass transitions temperatures of homopolymers A and B,wA and wB are mass fractions of A and B components of a copolymer accordingly,K is the ratio of glass transitions temperatures of the copolymer components (K DTgA=TgB), the q constant takes into account specific interactions in a system and,probablycan be used for the estimation of cross-links efficiency in a system. Glasstransitions temperatures of the Zn, Co, Ni polyacrylates (see Table 8.2), determinedby extrapolation of the glass transitions temperatures of the copolymers to the zerostyrene content, are close to Tg of the others metal poly(met)acrylates, for example,NaPMA (363ıC) [3] and LiPMA (359ıC) [3]. At the same time, Tg is lower for Crpolyacrylate (254ıC) [12].

An opportunity of processing of the ion-containing polymers from a melt is con-nected, first of all, with an increase in mobility of the ion pairs in the aggregatestructures at elevated temperatures. Thereupon, ionomers on the basis of noncrys-talline polymers with low Tg can be used as thermoplastic elastomers, i.e., they showproperties of the cross-linked elastomers at usual temperatures and their behavior issimilar to thermoplastics at elevated temperatures. It is typical especially for themaleate-modified ionomers, for example, KC or Zn2C neutralized salts of maleatecopolymers of ethylene/propylene [13] or K-maleate three block-copolymers ofstyrene- butadiene-styrene [14]. The features of these ionomers structures have beenanalyzed in Sect. 7.1. An increase in content of ionic groups and in neutralizationdegree results in the improvement of strength characteristics, and, as a whole, ofmechanical properties of the ion-containing polymers. It is seen from Fig. 8.1 that

100 200 3000–100Temperature (°C)

1.E–02

1.E–01

1.E+00

1.E+01

1.E+02

1.E+03

1.E+04

Sto

rage

mod

ulus

(M

Pa)

1 2 3

45

Fig. 8.1 Storage modulus as a function of temperature for starting non-modified (1) and modifiedwith maleic anhydride (2) ethylen/propylene copolymers and for potassium salts of maleate-gr-ethylene/propylene copolymers with neutralization degree of 25 (3), 50 (4) and 100% (5)


the module of elasticity and Tg (� �50ıC) for the maleate-modified copolymer ofethylene/propylene increases in comparison with the unmodified copolymer [13].

It testifies that ionic domains act as multifunctional physical cross-links that re-sults in an increase in the network density in case of the modified copolymer. As aresult of neutralization by metal cations, the life time of interacting groups is elon-gated due to replacement of weak polar interactions of anhydride groups by strongerionic interactions, though appreciable change of the module of elasticity does notoccur. Ionic interactions act up to higher temperatures; it is indicated by the widen-ing of the plateau of elasticity. Neutralization degree and nature of a cation are theimportant parameters influencing the mechanical properties of the ion-containingpolymers. With an increase in the content of ionic groups, tearing strength (TS)and elongation at break (EB) (Fig. 8.2) [13] increase due to the rise in the numberof ionic domains. However, inverse effects are observed at high concentrations ofionic cross-links (for example, at the ionic content >1:7 mmol=g for K-maleate threeblock-copolymer of styrene-butadiene-styrene (Table 8.3) or at decrease in molecu-lar weights of the ion-containing polymer [15]).

00

2

4

6

8

10

200 400 600 800 1000

Engineering strain (%)

15

2

6

3

4

Eng

inee

ring

stre

ss (

MP

a)

Fig. 8.2 Stress vs. strain for maleate anhydride modified ethylene/propylene copolymer (1) andits potassium (2, 3, 4) and zinc (5,6) ionomers with neutralization degree of 25 (2), 50 (3, 6) and100% (4, 6)

Table 8.3 Mechanical properties of potassium maleate styrene/butadiene/styrene triblockcopolymer [14]

The content of ionic groups TS (MPa)a EB (%)a PS (%)a

0 9.1 414 160.54 14.9 1,280 201.23 16.8 1,320 201.69 16.1 1,150 182.28 15.2 800 22aTS represents tensile strength, EB elongation at break and PSpermanent set


Carboxylated ionomers are rather effective also as compatibilization agents,especially in case of the immiscible polymers such as polyolefin and polyamide.Rheological and mechanical properties of the mixtures improved noticeably[16, 20]. For example, addition of 0.5% of a carboxylated ionomer resultsalmost in quadruple reduction of a dispersed phase size in a triple system poly-olefin/ionomer/polyamide [16]. With an increase in content or in neutralizationdegree of Li-EMAA, Na-EMAA, or Zn-EMAA as the modifying agent to the com-position “polyamide (PA6)-polyethylene of low density (LDPE)”, values of shearviscosity and elongation viscosity [17] rise. Most likely, interaction of counter-ionswith PA6 is more efficient than interaction of free carboxyl groups of EMAA.Though the cation nature (LiC, NaC, Zn2C) does not have appreciable influence,nevertheless it is noticed that Zn2C is the most effective cation for the mixtures withhigher PA6 content, while in case of LiC-EMAA the greatest viscosity is observedfor the mixtures enriched with LDPE.

At the same time, many binary polymer–polymer–ionomer mixtures frequentlyreveal full or partial incompatibility; it concerns, first of all, polyolefin–ionomermixtures. Decrease of growth rate of PP spherulites at crystallization from a melt ataddition of 5–10 mass% of an ionomer is observed in the “polypropylene/Zn-neutralized ionomer ethylene(80%)-methacrylic acid (10%)-isobutyl acrylate(10%)” system [21]. It is connected with a significant dissipation of energy ofa crystallizable front through detachment of the ionic domains that is typical forthe immiscible polymers with minimal interfacial interaction. It is accompaniedby coalescence of an ionomeric dispersed phase and by corresponding growth ofthe medium size of the domains. Similar laws are observed also for the polymericmixture HDPE/ethylene-co-methacrylic acid neutralized partly by NaC [22] despitethe fact that both polymers contain very close composition and structure olefinicunits. But it is necessary to note that such examples are not a rarity for the poly-olefin mixtures, as it was shown in case of LDPE/ethylene-co-acrylic acid [23]and LDPE/ethylene-co-methacrylic acid [24] systems, etc. DSC thermograms showtwo well expressed endothermic peaks corresponding to the melting points of theionomer (85ıC) and HDPE (125ıC) for the HDPE/ionomer composition equal to50/50 (mass%). DSC thermograms also show two peaks of crystallization at 75ıCand 112ıC with cooling at a rate of 10ıC=min that testifies the immiscibility ofthe components of such mixture. And as a whole, strength characteristics of thepolymeric mixtures of the considered type have a negative deviation from linearadditivity of the properties of the system’s components (Fig. 8.3). An increase inthe content of the ionomer in the mixture (i.e., when an inversion of phases occursand the ionomer forms a continuous phase) results in the strain hardening of thesystem expressing in a substantial increase in tearing strength. Such changes inthe properties of the polymeric mixture are caused, probably, by a network-likestructure due to the presence of physical cross-links with participation of theionomeric aggregates.

Salts of unsaturated carboxylic acids, in particular, Zn(II), Mg(II), and Na(I)methacrylates are widely used as cross-linking agents at solidification of unsatu-rated polyester resins and vulcanization of rubbers; the obtained composites are


1500

1000

500

00 20 40 60 80 100

a b

Ionomer content (wt %)

Elo

ngat

ion

at b

reak

(%

)

30

20

10

00 20 40 60 80 100

Ionomer content (wt %)T

ensi

le s

tren

gth

(MP

a)

Fig. 8.3 Elongation at break (a) and tensile strength (b) as a function of ionomer content forHDPE/EMAA-Na polymer blends

00

20

40

60

80

100a b

10 20 30 40 50

Filler content, phr

Tea

r st

reng

th, k

N/m

1

2

00

300

400

500

600

10 20 30 40 50

Filler content, phr

Elo

ngat

ion

at b

reak

, %

1

2

Fig. 8.4 Tear strength (a) and elongation at break (b) as a function of content of NaMAA (1) andcarbon (2) for ethylene/propylene rubber vulcanizate

characterized by appreciable improvement of mechanical properties and thermalstability [25–29]. For example, for the vulcanizate on the basis of magnesiumdimethacrylate and vinyl-acetate rubber, tearing strength is equal to 22.5 MPa andelongation at break remains at the level more than 300% even at the content ofmethacrylic salt up to 50 wt.part per 100 wt.part of the polymer [26]. At the sameweight fraction of Na methacrylate in the ethylene-vinyl acetate vulcanizate [27],wearing capacity of the composite reaches 102 kN/m, elongation at break exceeds400% (Fig. 8.4).

Similar properties were observed also in the systems based on ethylene-propylene-diene (EPDM) [30], styrene-butadiene [31], nitrile-butadiene [30, 32]and other rubbers. It is important that reinforcing effects of metal carboxylates


in the vulcanizates exceed appreciably in many cases the similar action of suchtraditional fillers as carbon black. Higher values not only of tensile strength, wear-ing capacity and elongation at break but also higher hardness of such compositeswere noted. There are some methods in which obtaining of a salt of unsaturatedcarboxylic acid and, accordingly, its following polymerization, are carried out ata stage of mixing and vulcanization of a rubber in situ,1 [27, 33–35]. The com-posites that are formed reveal specific cross-linked structure and morphology.Processes of homopolymerization of an unsaturated metal carboxylate and its graftpolymerization to a chain of an elastomer can occur simultaneously during vulcan-ization, thus promoting formation of ionic cross-links along with covalent ones. Thecross-linkage density in such systems is determined by the equilibrium swelling.So, in the article [34], volume fraction of EPDM in the swelling gel, Vr, (it is thecross-linkage density) was calculated by the following equation:

Vr D m0�.1� ˛/=�r

m0�.1 � ˛/=�r C .m1 �m2/=�s; (8.2)

where m0 is a mass of a sample before swelling, m1 and m2 are masses of a samplebefore and after drying, � is a mass fraction of a rubber in a vulcanizate, ˛ is amass loss of gum during swelling, �r and �s are densities of a rubber and a solvent,accordingly.

To divide contribution of covalent and ionic cross-links, a sample was subjectedto the swelling in the “solvent-hydrochloric acid” mixture, but Vrl was used insteadof Vr. Vrl characterizes the covalent cross-link density calculated by the (8.2). Thenthe difference between Vr and Vrl is, accordingly, the ionic cross-link density. Anincrease in the content of metal carboxylate in the vulcanizate, results in an increasein the gross and ionic cross-link densities as was shown by vulcanization of rubberswith the addition of Na [36] or Zn [33] methacrylates (Fig. 8.5).

Fig. 8.5 Effect of Zn MAAcontent on crosslink densityof ethylene/propylene/dienerubber. (1) gross crosslinkdensity, (2) ionic crosslinkdensity, (3) covalent crosslinkdensity

00

1

2

3

4

20 40 60 80 100ZDMA content (phr)

Cro

sslin

k de

nsity

(10

–4 m

ol/c

m3 )

1

2

3

1 We shall note that this approach is also very effective for the water-absorbing elastomers obtaining(see Sect. 8.3).


Fig. 8.6 The rate of curingof vinyl-acetate vulcanizatevs. filler content: (1)NaMAK, (2) carbon

100 20 30 40 50Filler content, phr

24

28

32

36

40

CR, (

1/m

in)

1

2

Fig. 8.7 Tensile strength vs.ionic crosslink density fornitrile/butadienerubber-magnesiummethacrylate vulcanizate

0.050.00 0.10 0.15Vr2

0

10

20

30

tens

ile s

tren

gth,

MP

a

Evidently, rise of the concentration of a metal salt promotes formation of graftmetal-carboxylated chains; it results in an increase in an ionic cross-link. Withrise of the of metal carboxylate content, solidification rate of an elastomer alsorises sharply as shown by the example of the vulcanizate methacrylate of sodium–ethylene-vinyl acetate copolymer [36] (Fig. 8.6).

Practically linear dependence of strength of the vulcanizate upon the ioniccrosslink density (Fig. 8.7) can testify the main role of the ionic cross-linksin the mechanism of improvement of the strength characteristics of elastomersin the presence of salts of unsaturated acids. Approaches for the realizationof copolymerization reactions of unsaturated metal carboxylate and the secondmonomer in situ at vulcanization of rubber were developed; it allows us to modifyproperties of elastomers at wider intervals [37–39].

Epoxy resins on the basis of bisphenol A and epichlorohydrin obtained in thepresence of Cr(III) acrylate are characterized by the increased thermal stability[26]. Moreover, modified in such a way epoxy polymers show conducting proper-ties (4:6–6:1� 10�10��1 cm�1). Earlier similar properties were revealed for blockcopolymers of Cr [40], Cu [41] and Ni [42] acrylates. Probably, improvement ofproperties of polymers and polymeric composites by means of chains cross-linkingis still far from its optimization.


8.2 Radiation Resistance, Photophysical and Optical Propertiesof Metal-Containing (Co)Polymers

Different processes take place under the influence of the ionizing radiations onan atom or a metal ion. These processes result, as a rule, in occurrence of low-energy electrons due to which various radiating effects in a polymeric matrix canbe realized. For that, content of the metal is essential. Thus, intensification of de-struction or cross-linking of a polymeric matrix occurs at the low concentration ofthe metal. At high metal content (30–50 mol%), copolymers get protective prop-erties from various kinds of radiation. Homopolymers of Mg, Zn, Sr, Cd, Cu, Hg,and Pb (met)acrylates and also their copolymers with MMA and tetraethyleneglycoldiacrylate have such properties [43]. Protective properties are efficiently combinedwith optical transparence of a material. So, transparency of the optical resins on thebasis of copolymers of Pb, Ba, Sr, Zn, Ti, Zr, Th and other salts of vinylbenzoic andmethacrylic acids and vinyl monomers exceeded 80% [44]. Relative transparencereached 88% in the case of the copolymers of Pb (met)acrylate with alkyl acrylates;this material was used for manufacturing of transparent filters of X-ray radiation[45]. Ternary copolymers St-MAA-Pb(MAA)2 [5] reveal similar optical properties,they are transparent in the region of visible light (Fig. 8.8).

The value of the refraction coefficient (nD) decreases with an increase in thecontent of a “free-metal” analogue, methacrylic acid (Fig. 8.9a) and, vice versa, risesat an increase in the content of a salt of methacrylic acid in the copolymer up to40 mass% (Fig. 8.9b).

This value of nD and the greatest calculated value of nD for the homopolymerPb.MAA/2 (1.622) in comparison with other comonomers allow to suppose thatadditives of Pb(II) methacrylate into the copolymerized system can improve consid-erably the refraction coefficient of optical resins as well as their radiation resistance.

200

0

20

40

60

80

100

300 400 500 600 700

Wave length, nm

Tra

nsm

issi

on, %

1

2 3

Fig. 8.8 UV–Vis spectra of Pb(II)-containing terpolymers at the metal methacrylate content of25 (1), 15 (2), and 5 wt% (3)

8.2 Radiation Resistance, Photophysical, Optical Properties of Metal-Containing Polymers 227

20 30 40 50 60

MAA content, wt.%

7034

35

36

37

38

39

401.580

1.570

1.560

1.550

1.540

1.530

1.520

ν Dn D

1 2

0 10 20 30

Pb methacrylate content, wt.%

34

36

38

42

40

1.570

1.565

1.560

1.555

1.550

ν Dn D

1

2

a b

Fig. 8.9 Dependence of the refraction coefficient and Abbey number on the content of methacrylicacid (a) and lead methacrylate (b) in styrene-MAA-Pb(MAA)2 terpolymer

Absorption of X-rays is quite high (97.2% for energy EXD 8:04 keV) even at lowcontent of Pb(MAA)2 (5 mass%) in a terpolymer, full absorption of X-rays is ob-served at 25 mass% of Pb.MAA/2. Copolymers of Pd monoalkyl itaconates are alsoused as the radiation-protective material [46]. Copolymers of Cd methacrylate andalkylmethacrylates in the form of a transparent lustreless material were applied forprotection against influence of neutrons [46].

Metal-containing polymers reveal interesting properties under the effect of non-ionizing radiations. Polymeric nature of a ligand causes specific luminescent andphotochemical properties of macromolecular complexes which are distinct from theproperties of low-molecular analogues. For example significant reduction of the flu-orescence intensity for Eu3C (almost by order) and Tb3C ions (by a factor of 4)[47,48] is observed at transfer from unsaturated methacrylic salt to its homopolymer.It is connected with presence of the effective concentration quenching of lumines-cence because of high metal content (up to 50 wt%) in a metal-containing polymer.Similar effects can be caused also by weak absorption by a metal ion and by absenceof effective intramolecular energy transport from the levels of a macromolecularligand to the levels of a radiating center. It is possible to choose two approaches forthe increase of fluorescence of the considered metal-containing polymers. Accord-ing to the first method, an organic ligand, capable of carrying out transport of theabsorbed energy to an ion of a rare earth element, is entered in a molecule. The al-ternative method consists in an increase in absorption capacity of the metal ion dueto change of its spatial environment. Such ligands as dibenzoylmethane [49, 50],1,10-phenantroline [51,52], salicylate [53] or naphthoate [54] anions can be used aschromophore groups in composition of the unsaturated salts of rare earth elements,rising probability of electron transport. If necessary, it is possible to enter severalsuch groups into a composition of a metal-containing polymer. So, for example, bi-functional copolymers containing two channels of energy transformation (carbazoleand phenantroline fragments which carry out transport of holes and electrons, ac-cordingly) were obtained by copolymerization of a monomeric complex on the basisof Eu(III) 4-vinyl or methacrylate [51, 52] with N-vinyl carbazole:


nyx

2

F3C

O

O

S

Eu

OO

N

N

CH CH

N

Energytransport

Emissioncenter

CH2 CH2

Appreciable improvement of the luminescent properties of the considered metal-containing copolymers is a consequence of such effective combination of varioustypes of functional groups in a macromolecular chain. First of all, it is revealed in anincrease in intensity of luminescence of metal-containing copolymers in comparisonwith monomeric salts of rare earth elements. As can be seen from Fig. 8.10, intensityof luminescence at excitation energy �D 300 nm for the copolymer of dinaphthoato-acrylate Eu(III) with methyl methacrylate (MMA) is almost eight times more thanfor the monomeric complex, though positions of an emissive spectrum are identicalin both cases [54].

Excitation spectra of luminescence are the evidence of energy transport fromchromophore groups to a lanthanide-ion. Wide diffusive bands in the 350–500 nmregion connected with electron transitions of ligands are observed in the corre-sponding spectra [49] of the metal-containing copolymer of acrylate(bisdibenzoyl

Fig. 8.10 Luminescence excitation (� D 615 nm) of Eu-dinaphtoate acrylate (1); polyMMA/Eu-dinaphtoate acrylate (2); PS/Eu-dinaphtoate acrylate (3). Luminescence spectra (� D 300 nm)of Eu-dinaphtoate acrylate (1) and PS/Eu-dinaphtoate acrylate (2) (Eu content of 2 wt%)


300 500 l, nm l, nm580 620

1

2

3

1

2

3

Intensity Intensity

a b

5 L6

←7 F

0

5 D2

←7 F

05 D

1←

7 F0

5 D0

←7 F

0

5 D0

←7 F

1 5 D0

←7 F

2

Fig. 8.11 Luminescence excitation (� D 612 nm, 77 K) (a) and luminescence (77 K) spectra ofeuropium acrylate(bisdibenzoylmethanate) (1), its copolymer with MMA (2) and europium poly-acrylate (3) (b)

methanate) Eu(III) with MMA besides the discrete lines caused by intraconfigura-tional f –f transitions of Eu3C. On the contrary, there is a set of narrow discretelines (Fig. 8.11) in the spectrum of europium polyacrylate; the most intensive bandcorresponds to the 5L6 7F 0 transition (395 nm), that increases an opportunity ofnon-radiative energy losses at the top excited levels of Eu3C.

The character of the spectrum indicates the absence of excitation energytransported from levels of a polyacid to the resonant levels of a metal that cor-relates with low luminescent ability of the given metal-containing polymer, aswas noted above. Dependence of the fluorescence intensity upon the content of ametal ion in a metal-containing copolymer has, as a rule, nonlinear character. So,copolymers of acrylate(bissalicylate) Tb with MMA and styrene [53] have maximalluminescence intensities at 3.8 and 2.8 wt% content of Tb, accordingly (Fig. 8.12).Similar dependences were also found in the work [54]. It should be noted thatpolymeric systems, in which acrylate complexes of Eu and Tb act as chemicallyfree doping agents, reveal a typical pattern of concentration quenching of emission.Special research [55] with use of the saturated carboxylate of rare earth elementsas an additive to a polymeric system have shown that entering of methacrylates


Fig. 8.12 Dependence fluorescence intensity on the content therbium ions in PMMA/therbium(III) acrylatebissalicilate (1), PS//therbium(III) acrylatebissalicilate (2), PMMA (3) andPS doped with therbium(III) acrylatebissalicilate (4)

of europium and terbium as comonomers into a macromolecular chain results inan increase in intensity of a characteristic bond of emission almost in ten times incase of Eu3C ion and in three times for Tb3C ion in comparison with the systemscontaining octanoates of these metals.

It is necessary to note, that various concepts about the mechanism of deactivationof luminescence in the considered systems exist. For many lanthanide polymers itis connected with an increase in effectiveness of cross-relaxation of excitation en-ergy with an increase in local concentration of metal ions in multiplets and ionicaggregates [56–59]. Electrostatic multipolar interactions [53, 60] and also migra-tion of excitation energy of ligands in macrocomplexes [61, 62] can introduce theconsiderable contribution to the processes of quenching of emission.

Thus, stabilization of a luminescent center due to covalent linkage of a metal-containing complex with a polymeric chain and its homogeneous distributionin a macromolecular chain during copolymerization of unsaturated salt allowto vary efficiently photophysical and fluorescent properties of metal-containingpolymers and to avoid processes of phase division and ionic aggregation incontrast to the systems obtained by physical mixture of a polymer and anadditive of complex of a rare earth element. For example, quantum yield ofphotoluminescence of the terpolymer of poly(vinylcarbazole-MMA-Eu-metha-crylate-bis-benzoylacetonate-1,10-phenantroline) is equal to 40.28%, it is severaltimes more than the corresponding value of low-molecular complexes anddoped polymeric systems [52] (and in some cases exceeds by an order). It ispossible to obtain various electroluminescent devices, for example, polymericlight-emitting diodes, on the basis of such materials combining functions of trans-port of charges and emissive layers, ability to monochromatic radiation and alsoopportunity of formation of films. The single-layer monochromatic diode was


obtained from copolymer of Eu-bis-thionylthreefluoroacetonate-4-vinylbenzoate-1,10-phenantroline with N -vinylcarbazole [51]. Its basic characteristics werethe following. Maximum brightness (126 cd m�2) and luminescence efficiency(0:56cdA�1) were reached at 22 V and 8 V with current density equal to 328 and0:2 mA cm�2 accordingly, that was comparable or even exceeded parameters ofsimilar devices on the basis of Eu3C complexes [63, 64].

The advantages of application of the considered type metal-containing polymersas fluorescent materials and laser-active mediums stimulate research of their thermaland photochemical resistance. Various factors influence the photochemical behaviorof metal-containing polymers, including composition and structure of a macrocom-plex, microstructure of a polymeric chain, coordination condition of a metal ion, etc.At UV-irradiation of polymeric complexes of Eu3C and Tb3C reduction of intensityof the basic absorption bands in the IR-spectra is observed and a band in the regionof 270–280 nm caused by carbonyl chromophore groups appears in the electronicabsorption spectra that testifies photodestruction of a macromolecular ligand [65].At the same time, intensity of luminescence of, for example, Tb3C polyacrylateduring UV-irradiation practically is not changed, while for macromolecular Eu3Cand Tb3C complexes on the basis of copolymers of acrylic acid and alkylmethacry-lates intensity of fluorescence of ions are not decreased as for their low-molecularanalogues, and, on the contrary, appreciably grows. It is the authors’ opinion thateffectiveness of phosphor building-up of metal-containing copolymers is connectedwith reduction of a degradation degree of energy of electronic initiation of a metalion on high-frequency vibrations of macroligands at photolysis, with bigger numberof coordination-unsaturated structures in copolymers and an increase in degree ofasymmetry of the nearest environment of lanthanide-ions. Electro-dipole 5D0 � 7F2

(Eu3C) transition is especially sensitive to the influence of the degree of asymmetryof the nearest environment of lanthanide-ions in comparison with 5D4 � 7F5 (Tb3C)transition having partly magnetic-dipole character. Tercopolymers of methacrylicacid, methacrylates of cobalt and copper (1 mass%) and fluoroalkylmethacrylates[66] or MMA [67] are characterized by stability of spectral characteristics to theeffect of UV-irradiation that allows to use them as strip and cutting color filter.Triple metal-containing copolymers of MMA, methacrylic acid and metal methacry-lates colored by rhodamine 6ZH showed higher photoresistance in comparison withcopolymers of MMA and methacrylic acid; the photoresistance increased in theseries Na1C < Ba2C < Pb2C < Er3C in dependence of the cation nature [68]. Pho-todestruction of the copolymers and the pigment were estimated by a relative changeof viscosity of their solutions (�=�0) and by a relative change of optical densityon the wave-length of maximum absorption (D/D0) before and after their irra-diation by full light of a mercury lamp. Changes of values of the initial rates ofphotodestruction w� and photo-decoloration wD in the considered series of metalsare represented in Table 8.4.

Along with immediate photo-stabilizing influence of salt groups, radius and po-larization coefficient of a salt cation, the tendency of appreciable reduction of w� �and wD at transition from the linear structure copolymers to the network struc-ture copolymers with various degrees of cross-link and with increase in part of


Table 8.4 Photoageing parameters of rhodamine 6G-colored terpolymersof methylmethacrylate with methacrylic acid and metal methacrylates(0.1 mol%) [68]

Metal Cation radius (A)Cation polarizationcoefficient

w� � 102 wD � 102

rel.unit/h

– – – 7.8 2.8Na 0.98 1.02 7.4 2.3Ba 1.43 1.40 7.0 2.0Pb 1.32 1.52 2.0 1.0Eb 2.04 2.88 1.8 0.5

stereoregularity of metal-containing copolymers is traced, that results in more fa-vorable conditions for dissipation and transfer of power of photo-excitation ofmacromolecules.

The important photophysical property of some metal-containing polymers is theability to selective light absorption. For example, typical metal light absorption isobserved in the 580 nm region in the copolymers of (meth)acrylate Nd with MMAor hydroxyalkyl(meth)acrylates [69, 70]. The given absorption superimposes on theemission spectra at use of these copolymers as color filters of metal-halide or mer-cury lamps; as a result, the effect of luster suppression is observed.

8.3 Water-Absorbing and Sorption Propertiesof Metal-Containing (co)Polymers

Metal-containing (co)polymers on the basis of (meth)acrylates of alkali metals havethe ability to swell in the corresponding conditions and reveal properties of hyper-absorbent materials due to significant number of ionogenic groups. Monitoring ofwater absorption is carried out, most often, by gravimetric analysis, methods ofcalorimetry and video- and telerecords are used for studying of swelling kinetics[71], technics of magnetic resonance visualization in low fields and dispersion fieldswas successfully applied for studying of distribution of spin density of diffusionof water in the polymeric sodium acrylate [72]. Volume of absorbed water can behundreds of times more than own volume of a sorbent. For example, the valueof sorptive capacity for the copolymers of Na acrylate with N,N 0-methylene-bis-acrylamide or N,N 0-dimethyl(acrylamidopropyl) ammoniumpropylsulfonate andN,N 0-methylene-bis-acrylamide is equal to 992 g H2O=g [73] and 721 g H2O=g[74] in deionized water and 106 g H2O=g and 83 g H2O=g in 0.9% solution ofNaCl, accordingly. In case of the cross-linked copolymer of acrylamide with Ca(II)methacrylate [75], value of the equilibrium swelling ability of a polymeric gel grewwith an increase in the content of methacrylic salt in an initial copolymer. Drivingforce of water penetration into a polymer is the gradient of chemical potential be-tween external water and drops of internal absorbed water. This gradient is higherfor distilled water than for saline solutions that results in higher water absorption.

8.3 Water-Absorbing and Sorption Properties of Metal-Containing (co)Polymers 233

Fig. 8.13 The dependence ofequlibrium swelling degreeQeq on pH for sodiumpolyacrylate hydrogel withcrosslinking degree N D 150.First cycle of swelling (blackdotes), the second (brightdotes)

The swelling ability of the sorbents on the basis of polyacrilat hydrogels can bedetermined substantially by the basic characteristics of an external saline solutionsuch as concentration, metal valency, medium pH. So, dependence of equilibriumswelling degree Qp on pH for hydrogels of Na polyacrylate with a various degreeof cross-link N (150, 75, 50, and 25 monomer units per one cross-link) has the max-imum at pH 6 for all samples (Fig. 8.13) [76].

The reduction of the degree of swelling in acidic mediums can be connectedwith substitution of NaC ions by HC ions and formation of weaker PAA electrolyte.Effect of counterions condensation and shielding of charges by excess of sodiumcations result in suppression of polyelectrolitic swelling in strongly alkaline medi-ums. Similar laws were observed also in case of the water-swelling elastomer on thebasis of chlorinated polyethylene and Li acrylate [77]. We shall note that the salt ofacrylic acid was obtained from corresponding reagents at the stage of mixing andvulcanization of the elastomer in situ, as it was earlier discussed in Sect. 8.1. Maxi-mum swelling degree of the elastomer corresponds to the molar ratio LiOH/AAD 1.High absorptive capacity (1,592 ml/g) in absorption of water was observed also forother hydrogel of the copolymer of acrylic acid and potassium acrylate with neu-tralization degree of 80% [78].

An increase in ionic force of a solution results in reduction of a difference ofosmotic pressure between a copolymer gel and a salt solution, for example, themonovalent cations [79] and as a result, in reduction of water absorption. However,for polyvalent cations, character of swelling can be caused also by their complexingwith carboxyl groups of a polymeric [73, 79, 80]. It was revealed that the xerogelof sodium acrylate with N,N 0-dimethyl(acrylamidopropyl) ammoniumpropylsul-fonate at its immersion into the 0.01 M solution of the polyvalent salt at first passedinto the swelling state and then absorption decreased, that could be initially con-nected with diffusion of water into a polymeric network and with the followingstage of an exchange by cations [79]. Similar effects were observed also in case ofthe copolymer of sodium acrylate with hydroxyethylmethacrylate (Fig. 8.14) [81].

It should be noted that according to the 23Na-NMR spectroscopy data, absorptionof water by sodium polyacrylate results in stronger low-field resonance frequency


1 10 100 1000 10000

Ionic strength, x10–5

0.00

100.00

200.00

300.00

400.00

Abs

orba

nce,

g/g

4

3

21

5

Fig. 8.14 Water absorbance with the crosslinked copolymer of sodim acrylate with hydroxyethyl-methacrylate at different concentrations of ions: NaC (1), Ca2C (2), Zn2C (3), Cu2C (4), Fe3C (5)

shift of 23Na (�6:6 ppm) below, than for usual hydrated sodium ions. It testifiesthe formation of intermolecular hydrogen bonds with carboxyl groups of polyacry-late by molecules of water, surrounding sodium ions, and the formation of a gelstructure [72]. Moreover, the sufficiently narrow (line width, measured on the halfof the maximum intensity, is equal to 1.2 kHz) and symmetric signal of 23Na in-dicates presence of mainly isolated sodium ions in a polymer. At the same time,in the ionomeric copolymer of zinc acrylate, water molecules (up to 6.5 H2Omolecules per 1 Zn(II) ion) are localized in the ionic domains [82]. High initialrate of water absorption is also typical for the analyzed absorbent gels; for example,it is equal to 208 g H2O=min for the copolymer of sodium acrylate with N,N 0-methylenebisacrylamide [73]. The modified potassium polyacrylate absorbs 6,200 gH2O=g during the first 10 min and 9,600 g H2O=g – during 15 min [83]. So effec-tive water-absorbing properties of metal-acrylate copolymers predetermine areas oftheir application – manufacturing of various water and blood absorbents as well asproduction of diapers, bandages, medical tampons, retardants of water evaporationin reservoirs, and also as water-shutoff agent at oil production, as agent of wateryield of muds, etc. These data are presented, mainly, in patent literature.

The recently offered sodium polyacrylate composites and nanocomposites onthe basis of mineral clays have improved sorption characteristics [84, 85]. Compos-ites with hyper-absorbent properties on the basis of organomontmorillonite [86],kaolin [87], bentonite [88], etc. were obtained. By the composition, minerals arehydrated layered aluminum silicates with reactive groups on a surface. Their in-teraction with functional groups of polymers results in formation of a compositewith high absorbing capacity. For example, by graft polymerization of Na acrylate


Gibbsiteoctahedral

layerSilica

tetrahedrallayer

O

AI

Si

HOOC HOOC

HOOC

HOOCHOOC

HOOC HOOC

HOOC

OHO

HO

OH

HOHO

HO

OH

OH

OHOHOH OH

OH

OH OH

HO

OO O

O O O

O

OO

OO

OO

O

O

(M units)

(G units)

a b

Fig. 8.15 Schematic structures of kaolin (a) and polysacharide units of Na alginate (b)

on a surface of Na alginate in the presence of kaolin and a cross-linking agent, thehydrogel with ability to absorb water in a quantity of 400 times more than its masswas synthesized [87]. The schemas of the kaolin and Na alginate structures arepresented on the Fig. 8.15.

It is interesting to note, that alginates are bio-degrading natural polymers; theyare linear polysaccharides consisting of (1,4)-bonded ’-L-guloronate (G-units) and“-D-mannuronic acid (M-units) residues. Hydrogels on the basis of mineral clayscan be effective for water utilization in droughty and deserted regions. For exam-ple, bentonitic composites have ability to retain up to 76% of water at 60ıC during40 h [88].

The interest in hydrogels including hydrogels on the basis of acrylates of al-kali metals essentially increased in the last few years due to their ability to changephase depending on temperature, pH, ionic force and solvent; i.e., hydrogels are ableto reveal the critical phenomena in response to external influence that is the char-acteristic of smart polymers [89–94]. The majority of such hydrogels are usuallyreceived by chemical [95] or physical [96,97] cross-link of water-soluble polymers.The mechanically cross-linked hydrogel on the basis of terpolymer of acrylamide,sodium acrylate and cyclic macromonomer was obtained by formation of a poly-meric network due to piercing of a functionalized macrocycle in situ [98]:

nCH CO

O

C

Ph

N

xy

n

initiator

CONH2

CONH2

N

Ph

C

O

CH2

CH2

CH2

CH2

CH2

CH2COCHC5H11

C5H11CO2K

CO2K


200

5

10

15

20

25

25 30 35 40 T, °C

–6.5

–4.5

–2.5

–0.5

dr / dT (deg–1)

12

3

r

Fig. 8.16 Degree of swelling (r) of the hydrogel of N -isopropyl(acrylamide)-sodium methacry-late (1 mol%)- N,N 0-methylenebis(acrylamide) (0.5 mol%) vs. temperature in direct (1, 2) anddifferential coordinates (3). Data were obtained during heating (1) and cooling (2)

The polyelectrolyte received in this way has a higher swelling capacity (initialdiameter d0 D 7:0 mm) in comparison with a chemically cross-linked gel (d0 D1:9 mm), and also bigger volume shrinkage (d /d0 < 0:25) in the 0.2 M solutionof copper chloride. The behavior of hydrogels is efficiently controlled by an ex-change of counter-ions by protons and formation of dimeric carboxyl groups dueto hydrogen bonds, as was shown by the example of sodium polyacrylate cross-linked by aluminum ions, subjected to periodic substitution of an aqueous solventby a fresh portion (by 100 ml with an 24 h interval) [97]. Two relaxation processestook place in non-monotonic behavior of a gel swelling: swelling at the first stage,then – shrinkage at the second stage resulting in a smaller degree of swelling thanfor the initial gel. Heat-sensitive swelling-shrinkage transition was observed for thecopolymers N -isopropylacrylamide (NIPA) with acrylate or methacrylate of sodium[95]. As can be seen from Fig. 8.16, experimental points corresponding to shrink-age and data received at cooling are in good agreement among themselves, andchange of a gel volume is thermo-reversible. The minimum on the differential curvedr /dT .r � wh/wx, wh are the mass of the swollen gel plate, wx is the mass of thedry gel plate) corresponds to the lower critical temperature of swelling of a hydro-gel. It is important, that r values for the copolymers of NIPA with Na acrylate ormethacrylate were higher than for the copolymers of NIPA with their free-metalanalogues – AA and MAA [99], i.e., inclusion of strong electrolytes, (meth)acrylicsalts, into a hydrogel promotes rise of water absorption.

Hydrogels of poly(2-hydroxy ethylmethacrylate) reveal significant changes inability to swelling and also in dynamic and equilibrium properties in dependenceon pH and ionic force of solutions at use of the comonomer of acrylic acid or itssodium or ammonium salts (Table 8.5) [100, 101].

As can be seen from Table 8.5, parameters of the cross-linked hydrogel networkare very sensitive to change of medium pH: molecular weight (Mc/ between nodes


Table 8.5 The parameters of hydrogel networks on the data of equlibrium swelling at differentpH and 37ıC (I D 0:1 M)

Cross linkedagent/monomer � 102

(mol/mol)

The volume partof swellingpolymer Mc (g/mol)

Crosslinkdensity (q)

Pore size,� (A)

HEMA-co-AA-co-NaAA (cross linked agent EGDMA)pH 2.0 1.90 0.607 209 0.586 8:78

pH 3.0 1.90 0.506 880 0.139 19:02

pH 5.0 1.90 0.209 1;916 0.064 37:70

pH 7.0 1.90 0.164 2;486 0.049 46:80

pH 8.0 1.90 0.160 2;667 0.046 48:80

HEMA-co-AA-co-NH4AA (cross linked agent EGDMA)pH 2.0 1.90 0.533 502 0.243 14:17

1.68 0.519 530 0.238 14:50

0.84 0.510 565 0.210 15:50

pH 3.0 1.90 0.484 1;352 0.090 24:00

1.68 0.400 1;520 0.070 29:00

0.84 0.140 3;672 0.032 60:90

pH 5.0 1.90 0.201 1;843 0.066 37:70

1.68 0.150 3;396 0.035 57:10

0.84 0.090 7;003 0.017 97:70

pH 7.0 1.90 0.153 2;610 0.047 49:10

1.68 0.121 4;571 0.026 71:20

0.84 0.072 9;939 0.012 125:10

pH 8.0 1.90 0.148 2;720 0.045 50:70

1.68 0.110 5;250 0.023 79:00

0.84 0.070 10;229 0.012 127:60

of cross-link and value of � grows with reduction of the cross-link degree and thevolume fraction of the swollen hydrogel. For example, Mc grows from 565 up to10,229 g/mol at pH change from 2 to 8. It can be connected with the fact that atan increase in pH –COONH4 and COOH are exposed to full dissociation and dis-sociated ions are kept inside a hydrogel, it results in an increase in the osmoticpressure and swelling degree. It is necessary to note, that pH-sensitive behavior ofcross-linked hydrogels is very important for creation of system of the controllableand directed drugs delivery on their basis. Rate of drug release, their prolongedeffect will depend from pH of medium, cross-link degrees and kinetics of a hydro-gel swelling. Pore sizes � also have essential value; they are within the limits of8.78–127.6A at pH 2.0–8.0 (Table 8.5), that is enough for penetration of moleculesof drug substances, including peptide and protein substances, in a hollow of a hy-drogel. In the last few years, much attention has been given to the questions oftransport of drugs and proteins using cross-linked polymeric networks on the ba-sis of copolymers of acryl acid and its salts with 2-hydroxyethylmethacrylate andN -isopropylacrylamide [102–105].


8.4 Sorption Properties of Metal-Containing (co)Polymers

Metal-containing polymeric sorbents reveal high effectiveness in concentration andlinkage of trace quantities of organic molecules. The cross-linked polyacrylate of Feobtained by polymerization of Fe(III) acrylate at � -irradiation (0.5 Mrad) at pres-ence of the cross-linking agent, ethylene glycol dimethacrylate, links significantlymore phenols in comparison with poly(acrylic) acid traditionally used for these pur-poses (Table 8.6) [106].

As it is seen, sorptive capacity of the metal-containing polymeric sorbent in-creased by 68, 92 and 104% in a series of phenol–chlorophenol–nitrophenol sub-strates. We shall note that polarity of substrates molecules also grows in thissequence.

As a whole, hydrophilic character of polymeric metal-containing complexesattracts attention of researchers to creation of the polymeric membranes on theirbasis for division and concentration of liquid organic mixtures [107–110]. Opportu-nity of regulation of swelling degree of cross-linked metal-containing copolymersthrough the formation of ionic cross-links is very important for these purposes.For example, copolymers of methyl methacrylate and methacrylic acid, neutralizedby Fe(III) and Co(II) ions [111] were used as such polymeric membrane for divi-sion of benzene/cyclohexane mixture. It was found that insertion of metal ions andcross-link of polymeric chains with their participation increases penetrability andselectivity of penetrability of an organic mixture through a polymeric membrane.At that, perfusion characteristics (penetrability rate, factors of sorption and diffu-sive selectivity) of the obtained membranes are various for MMA–MMA–Fe(III)and MMA–MMA–Co(II), that, probably, is connected with the formation of variousmetal-containing complex structures.

Cross-linked metal-containing copolymers are also significantly interesting forsorption and concentration of metals ions. The methods traditionally used for utiliza-tion of toxic metal ions such as chemical precipitation, electroflotation, processesof ion-exchange reactions and osmoses, are frequently characterized by relativelylow effectiveness, high energy expenditures, etc. Polymer-mediate methods of ul-trafiltration [112–114], sorptions on polysaccharides [115–117] and on polymerichydrogels have been actively developed in last years. Synthetic polymeric materi-als are also widely used due to their renewable origin and ability to remove metalsions selectively and practically completely. Polymers with carboxyl functionalgroups occupy the main part among such materials. Increased sorption propertiesof the cross-linked copolymer of acrylic acid and poly(acryloylmorpholine) withrespect to ions of heavy metals are just connected with carboxylated function, as ho-mopolymer of the poly(acryloylmorpholine) reveals very weak affinity to metal ions

Table 8.6 Sorption degree of phenols with sorbents (g/100 mg)

Sorbent Phenol Chlorophenol Nitrophenol

Polyacrylic acid 930 ˙ 12 1221 ˙ 9 1926 ˙ 8

Iron polyacrylate 1559 ˙ 21 2342 ˙ 16 3936 ˙ 7

8.4 Sorption Properties of Metal-Containing (co)Polymers 239

despite the content of tertiary amino groups in the composition [118]. High sorptivecapacity to Co2C and Cu2C ions (200–300 mg/g) was revealed for the copolymersN -phenylmaleimide and acrylic acid [119]. Poly(ethylene terephthalate)-gr-itaconicacid/acrylamide is not only the effective sorbent for Cu2C (7.73 mg Cu2C=g), Ni2C(13.79 mg Ni2C=g) and Co2C (14.81 mg Co2C=g) ions, but it is also selectivefor Cu2C ions at their combined linkage at pH 4 [120]. Probably, sorption se-lectivity in this case is caused by the formation of a more stable complex withCu2C ions, that was revealed for chelates of Cu2C and Ni2C copolymer of ita-conic (IA) and 2-acrylamido-2-methyl propanesulfonic (AMPS) acids [121]. At thesame time, research of competitive sorption from the mixture of water solutions ofPb2C, Cd2C and Cu2C ions by the same cross-linked copolymer P(AMPS-co-IA)(80:20 mol%) have shown, that removal of metal ions occurred in the following se-quence: Pb2C > Cd2C > Cu2C and the initial sorption rate was equal to 33.06, 12.92and 12.53 mg/g min accordingly [122]. But at that, presence of the IA residues in thecopolymer results in an increase in the initial rate of removal of Cu2C in comparisonwith the homopolymer AMPS (5.27 mg/g min). Copolymers of cellulose-gr-acrylicacid [123, 124] and also hydroxyethylcellulose-gr-poly(acrylic) acid [125] have se-lective character of sorption to Pb2C ions in a mixture of the above mentionedcations. It is interesting to note, that double increase in the Cu2C ions concentra-tion in the initial mixture of metal ions (at the equal molar ratio of the remainingmetal ions) results in the reduction of sorptive capacity to Pb2C and Cd2C ions(0.49 mmol Cu2C=g, 0.43 mmol Pb2C=g and 0.26 mmol Cd2C=g), that can meansthat sorbent becomes selective with respect to Cu2C ions.

Studying of the mechanism and kinetics of sorption of metal ions by poly-meric hydrogels testifies that removal of metal is the very fast process, adsorptionequilibrium is reached quickly enough, and linkage of metal occurs on the adsorp-tive, ion-exchange or chelated mechanisms. So, sorption isotherms of Ni2C [126]or Cr6C [127] ions by the hydrogels of poly(acrylamide--acrylate Na) or poly-methacrylate Fe(III) [128] are well described in linearized Langmuir coordinates:

Ce

qeD 1

Q0bC Ce

Q0

; (8.3)

where Ce is the equilibrium concentration of metal ions in a solution (mg/L), qe isthe content of a metal in a sorbent (mg/g), Q0 is the maximum sorption (mg/g), b isthe Langmuir constant (L/mg). As can be seen from Table 8.7, received graphicallyvalues of constants of sorption isotherms for the Ni2C-poly(acrylamide-co-acrylateNa) system are in accordance with the data of regression analysis.

It is typical that sorptive capacity of the gel grows with an increase in a molefraction of Na acrylate in a copolymer; at 44 mol% content of Na acrylate 84% ofNi2C ions is linked for the solutions with the initial concentration equal to 20 mg/L.However absorption degree of Ni2C ions reduces for higher concentration.

The ability to form a ternary polymer–metal ion complex was revealed for thecopolymer of sodium acrylate with maleic anhydride and diethylenetriamine dur-ing adsorption and division of trace quantities of Au3C, Ru3C, Bi3C and Hg2C


Table 8.7 Isotherm constants Ni2C-ions sorption with poly(acrylamide-co-sodium acrylate) hydrogel at different temperatures

Temperature (ıC) Q0 (mg/ga) b (L/mga)

30 4.52 (4.03) 0.646 (0.599)40 4.30 (4.31) 0.283 (0.281)50 3.41 (3.42) 0.258 (0.253)aIn brackets the data of regression analysis are given

ions from aqueous solutions that was expressed in sufficiently high sorptive capac-ity with respect to the above mentioned metal ions (220, 105, 155 and 176 mg/g,accordingly) [129].

The technique of molecular recognition is especially suitable for the obtaining ofsuch type sorbents [130–133]. It is known, that such systems reveal, for example,high substrate selectivity, at the same time they can have low sorptive capacity.In this connection, metal-containing monomers give supplementary functionali-ties for template effect at linkage of metal ions or organic molecules [134–137].(Co)polymerization of metal (meth)acrylates in the presence of a cross-linking agentwith the subsequent removal of a metal by a suitable eluent results in the formationof a cross-linked copolymer with preservation of the favorable for complexationwith the given ions conformation of a macromolecule of an initial metal-containingcopolymer.

"template" polymer

M1 + M2 + M3 ...

M1 M1 M1

M1

M1 M1

M1

M1

M1

Cross-linking Removing M1

According to this schema, the cross-linked macroporous copolymers of Cu(II)methacrylate and their macromolecular templates, having selective sorption proper-ties with respect to Cu(II) ions, were obtained (Table 8.8) [135].

Bonded “own” ions make 60–70% from initial content of ions in a copolymerand their selective adsorption is realized from sufficiently diluted solutions(10�3–10�5 M). It is important for concentration and extraction of metal ionsat their content, for example, in the polluted waters at the level lower than thedetecting level.

The original method of the precipitation polymerization [138] was offered for theobtaining of the metal-template polymer at copolymerization of Cu(II) methacrylatewith dimethacrylate of ethylen glycol (DMEG); the (DMEG:Cu(MAA)2) molar ra-tios were varied from 2 up to 14. Polymerization was carried out in isopropanolwith the use of a rotary evaporator for the formation of homogeneous micro-spheres with the sizes from 1 up to 4 mm in dependence on the polymerization


Table 8.8 Effective sorption capacity (in (mol/g) of “copper tuned” and analogous “untuned”polymers cross linked by ethylene glycol dimethacrylate with respect to the metal cationsa

Copolymers Zn2C Cd2C Pb2C Cu2C

Copolymer of [Cu(OCOC(CH3/DCH2/2 H2O (1) 10:3 7:4 15:5 45Untuned polymer 1 4:6 4:6 16:5 12.5Copolymer [Cu(OCOC(CH3/DCH2/2 Py (2) 9:7 7:8 15:2 49Copolymer [Cu(OCOC(CH3/DCH2/2 VPy (3) 12:4 5:7 6:7 52Untuned polymer 3 3:2 4:1 12:6 30aSorption capacity: salt concentration, 4:08 � 10�3 mol=L, 25ıC, 2.5 h, pH 4.7

Fig. 8.17 SEM image of Cu(II)-template polymer microgranules prepared at different crosslink-ing agent concentrations: (a) 2, (b) 6, (c) 10 and (d) 14 molar ratio DMEG:Cu(MAA)2. Initiatorconcentration: 4 wt% AIBN, monomer concentration: 14 wt/vol% of solvent

conditions (Fig. 8.17). Sorptive capacity of the template polymer and selectivitywere determined after removal of Cu(II) ions from the cross-linked copolymer. Ad-sorption equilibrium was reached in 10 mines and absorption of a sorbed ion was90% from the initial contents. Maximum sorptive capacity with respect to the Cu(II)ions was 0.331 mmol/g, that was 40–200 times more than linkage of other ions andexceeded by order capacity of a non-arranged cross-linked hydrogel.

The opportunity to use the considered type metal-containing copolymers forcreation on their basis of selective sorbents for radionuclides seems to be suit-able. Using the above described approach and proceeding from the correspondingmonomeric salts, it is possible to obtain the cross-linked copolymers, prearranged,for example, to the Sr2C [136] or U4C [139] ions:


RemovingUO22+

Cl O

OH

OCl

HO

Cl

O

OO

O

U

O

O

Cl

Copolymerization with crosslinkingCl

O

OO

O

U

O

O

Cl

OH2

OH2

H2OH2O

Repeated linkage of uranyl ions in the presence of a strong complexing ionsreveals high selectivity of a template copolymer with respect to UO2

2C: the factor ofselectivity (ratio of the quantity of a sorbed “own” ion to the quantity of a “strange”ion) is equal, for example, in case of competing ions, to Cu2C 8.8, VO2C 3.8, Al3C8.6, Fe3C 8.1, Th4C 2.7 [139].

Sorptive capacity decreases, as a rule, with an increase in the cross-linking de-gree. So, there is an optimal area of compositions when sorption properties arerevealed most efficiently for the copolymers of Sr2C acrylate with ethyleneglycoldimethacrylate [136]: the factor of selectivity is 20–27 at the content of a cross-linking agent 42–53 mol% (Table 8.9).

Probably, at higher M2 content in a copolymer, decrease of selectivity occursbecause of change of the mechanism of ions sorption which is carried out not onlyby the “prearranged” centers, but also by others, in particular, ester groups by thecoordination mechanism.

It is interesting, that triple copolymerization137 (M3 – styrene) with participationof strontium diacrylate and DMEG is accompanied with a decrease in a copolymeryield with an increase in M3 part in a comonomeric mixture, and a decrease in

Table 8.9 Sorption properties of the copolymers of Sr.OCOCHDCH2/2 (M1) with dimethacrylateethyleneglycol (M2)

Copolymercomposition (%)

Amount [Sr] in theinitial sorbent(mg-equiv/g)

Metal concentration aftersorption (mg-equiv/g)

Selectivity factorM1 M2 [Sr] [Ba]

61 39 6.03 – – –58 42 5.73 2.74 0.10 27.449 51 4.84 3.07 0.14 21.946 54 4.5 1.23 0.06 20.518 82 1.78 0.54 0.78 0.697 93 0.68 0.80 0.96 0.83


Table 8.10 Copolymerization of Sr(CH2DCHCOO)2 (M1) with dimethacrylate ethyleneglycol(M2/ and styrene (M3) (70ıC, ethanol, 2 mol% AIBN)

Composition ofmonomermixture (mol%) Copolymer

yield (%)

Amount [Sr] incopolymer(mg-equiv/g)

Metal concentrationafter sorption(mg-equiv/g)

Selectivity factorM1 M2 M3 [Sr] [Ba]

9 16 75 32 0.91 0.50 0.32 1.527 19 54 64 3.75 0.83 0.55 1.552 22 26 92 4.96 0.96 0.70 1.3

sorption properties of a copolymer and reduction of its selectivity (Table 8.10). It ispossible to suppose, that corresponding optimization (by cross-linking degree, thenature of a cross-linking agent and the third comonomer, and also by conditionsof sorption, medium pH) of this method will allow to obtain effective sorbents forthe linkage of strontium, including radionuclide, at presence of significant excess ofaccompanying ions (Ca, Ba, Na, To, Mg, etc.).

With the purpose of creation of polymeric sorbents, proof against effect ofclimatic factors and corrosive mediums, the method allowing to obtain the “pre-arranged” sorbents on the basis of inert bearers such as polyethylene was developed[136]. This method is based on graft polymerization and copolymerization of stron-tium diacrylate to a surface of a polyethylene-powder. This powder was exposedto � -irradiation 60Co (a radiation dose is equal to 10 Mrad) on air for creation ofthe radical centers initiating graft copolymerization of Sr.CH2DCH�COO/2 withDMEG (333–353 R, methanol, 25 mol.% DMEG). Under these conditions, the con-tent of grafted Sr2C was equal to 1:2 � 10�4g-equiv/g PE, that corresponds to thethickness of a grafted layer 30–50 A. A sorbent in which the grafted layer is “prear-ranged” to the strontium ions is formed after removal of the initial Sr2C. However,sorptive capacity of such polymer is low (30–40% from the content of the graftedstrontium diacrylate) because of a small specific surface of the PE-powder. Temper-ature dependence of linkage of Sr2C by such polymer is shown on Fig. 8.18. It canbe seen that sorptive capacity of the polymer grows and reaches the optimal valuewith rise in temperature. Apparently, use of the polymers with the developed surfaceas substrates, and also optimization of processes of graft homo- and copolymeriza-tion’s for the formation of the graft layer can improve sorption properties of suchgraft polymers.

In this connection, polymeric hydrogels, sorption properties of which are easilycontrolled, in dependence on composition of copolymers, swelling degree, thick-nesses of a cross-link, etc are especially attractive for utilization of radioactivenuclides. Adsorption of uranyl ions on poly(acrylamide-co-acrylic acid) increaseswith an increase in the content of acrylic acid in the hydrogel and concentration ofuranyl ions [140]. The adsorption isotherms have S�shaped character (Fig. 8.19)and sorption values are 70–320 mg of UO2

2C=g and 70–400 mg of UO22C=g from


Fig. 8.18 The dependence ofthe amount of boundedSr2C-ions on temperature(sorbent PE-gr-PAA)

30100.8

1.0

1.2

1.4

1.6

50 70 90T, °C

[Sr]fx × 105, mol / g

1000 150050000

100

200

300

400

500

600

700

800

C°(mgUO2+L–1)

q e(m

gUO

2+g–1

)

1

2

3

Fig. 8.19 The adsorption isotherms of uranyl ions from aqueous solutions of uranyl nitrate ontopoly(AAm-co-AA) hydrogels at pH 7.0 and 25ıC. Initial molar ratios of AAm/AA 30/70 (1), 20/80(2), and 15/85 (3)

the solutions of uranyl-nitrate and uranyl-acetate accordingly, in dependence on thecontent of acrylic acid in the hydrogel. As a whole, sorption properties of the poly-acrylamide hydrogels on the basis of copolymers of unsaturated carboxylic acidswith respect to the ions of heavy metals are in correlation with their ability to swellin water [140–142].

8.5 Catalysis by Macromolecular Metal Carboxylates 245

8.5 Catalysis by Macromolecular Metal Carboxylates

Polymeric metal-containing complexes are widely used as immobilized catalysts ofvarious processes [143,144]. Immobilization of metal-containing complex catalystson the polymeric bearers allowed to raise their stability and selectivity, to simplifystages of division of a product and a catalyst in many cases. Recent tendencies ofdevelopment of catalysis by polymer-linked metal-containing complexes and alsoa specific role of macroligands (including macroligands with carboxylated func-tions) in the catalyzed processes, have been analyzed in detail in the recent reviews[145, 146]. Data concerning catalytic properties of macrocomplexes on the basis ofpolymeric acids and macroligands with carboxyl groups in various reactions arecovered sufficiently fully in numerous monographs and reviews [144, 147, 148].Therefore, the basic attention will be focused on some catalytic reactions withparticipation of metal-containing polymers obtaining by homo-copolymerization ofunsaturated carboxylic acids.

As has been noted above, traditional methods of immobilization of metal-containing complexes are multi-stage; the processes accompanying them can becomplicated by a lot of conversions that results in composition heterogeneity of theformed products. It is possible to overcome these restrictions by use of the hetero-geneous catalysts obtained by (co)polymerization of metal-containing monomers[149]. The spectrum of the reactions catalyzed by such catalysts is very wide –hydrogenation of alkenes and functionalized olefins, oxidation of various sub-strates, polymerization of alkenes and alkynes, etc. Products of polymerizationsof the unsaturated carboxylates of d -elements are especially suitable in this classof macromolecular complexes. As a rule, they are effective in the same reactionswhich are catalyzed by usual metal-containing complexes, though the presence ofsuch unusual ligands in a coordination sphere causes specificity of their behavior.Moreover, as it was noted in Chap. 4, many of metal carboxylates, first of all onthe basis of dicarboxylic acids, are supramolecules with a structure from unidi-mensional chains, two-dimensional layered and three-dimensional coordinationpolymers:

OO

MM

M M

MM

M

MM

MM

M

MM

MM

OO

OO

O

OOO

O

OO

O

OOO

OO

O

OOO

O

OO

OO

O

O

O

O

OOO

O

MM

OOO

O


As a rule, the products formed are insoluble in the usual reaction mediums, andthus, can potentially be used as heterogeneous catalysts. In the last few years, suchcompounds have been considered as an independent class of fixed metal-containingcomplexes, so-called self-supported catalysts [150, 151]. They are highly organizedfunctional organometallic ensembles in which metal centers are connected amongthemselves by means of polydentate ligands with the help of coordinate bonds.So, the fumarate complexes of rhodium ŒRh2.trans-O2C–CHDCH–CO2/2n arevery active in catalytic hydrogenation of olefines [152, 153]. In principle, bimetal-lic complexes of this type can also be obtained. For example, such complexesas Rh-containing carboxylated polymers with metal-porphyrinic units [154, 155],which are catalysts of hydrogenation of propylene, ethylene, 1-butene. Synergeticeffect of a macrocomplex action is revealed in these reactions. It lies in the factthat both metal centers work. Activation of hydrogen atoms occurs on binuclearRh centers, while an increase in local concentration of olefin in micropores oc-curs due to coordination of a metal atom of a porphyrin ring with olefin. Thus, theopportunity of designing active centers on a molecular level at the obtaining of coor-dination polymers is an effective way for the synthesis of multimetal heterogeneouscatalysts.

The increased thermal stability and stability to corrosive medium of the con-sidered metal-containing polymers allow us to use catalytic systems on their basisin hard regime conditions (for example, at elevated temperatures, in oxidizing at-mosphere). We shall consider several examples of reactions with participation ofmetal-containing polymers.

8.5.1 Catalytic Reactions of Oxidation of Hydrocarbons

On the one hand, these reactions reveal features of the oxidizing catalysis under theaction of polymer-immobilized complexes, and on the other hand – they have manycommon features with enzyme catalysis since they proceed at low temperatures,demand low quantity of a catalyst and have high selectivity [156]. For example, oxy-gen oxidation of cyclohexene is the model reaction for research of the mechanism ofcatalytic and not-catalytic oxidation of olefines. Oxidation of cyclohexene proceedson two parallel routes: with participation of >CDC< orDC–H bonds:

(8.4)

The main products of liquid-phase oxidation are 2,3-epoxycyclohexane,cyclohexene-1-ol-2 and hydroperoxide of cyclohexyl (HPCH).

The mechanism of this reaction was investigated in detail by the example of Co2Ccomplexes, connected with various types of carboxyl-containing polymers [157,158]. At use of Co.AcAc/2 as the catalyst (Fig. 8.20), the process is characterized by


Fig. 8.20 Oxidation ofcyclohexene in the presenceof cobalt-containing catalysts:(1) Co(AcAc)2 , (2)PE-gr-Co2C-PAA, (3)copolymer of cobalt acrylatewith styrene

0

0.1

0.2

0.3

0.4

20 40 60 80time, min

1 2 3

Adsorption of O2, mol / L

Fig. 8.21 Inhibition ofcyclohexene oxidation withdimer Ph–Ph. Œcyclohexene

D 5 mol=L, catalyst PE-gr-Co2C-PAA, 328 K, [Ph–Ph],mol/L: 1:7 � 10�4 (1, 3, 4),3:4 � 10�4 (2), 1:7 � 10�5

(5). Arrows indicate themoment of inhibitor adding

20 40 600

1

2

3

4

5

3

2

4

5

1

time, min

Adsorption of O2, mol / L

the induction period with the subsequent fast attainment of the maximum rate andits further decrease. The induction period is absent at catalysis by macrocomplexes,oxidation rate remains constant, catalysts are active up to deep oxidation rates andcan be used repeatedly after their separation from the reaction medium.

The composition of the formed products is almost identical, the main prod-ucts are HPCH, cyclohexenone, cyclohexenole and cyclohexene oxide. Oxidationof cyclohexene by such systems is the heterogenic-homogeneous chain process ac-companied by release of radicals into volume. It was confirmed by a method ofinhibitors: by introduction of an acceptor of free radicals – dimmer of 1,2-bis(4,40-dimethylaminophenyl-1,2-diphthaloylethane (Ph–Ph) – into a system. Addition ofan inhibitor on the part of stationary development of the reaction (Fig. 8.21) resultsin occurrence of the braking periods independent of depth of oxidation.


Calculations show that the initiation rate at the initial moment of time is 30 timesless than on the stationary part. Hence, superficial processes determine rate of gen-eration of chains; free radicals are not formed in volume. In the beginning of thereaction, when ROOH are absent in the system, free radicals are formed by the re-action of the polymer-linked cobalt with oxygen:

]–Co2+ + O2 ]–[Co3+ ...O•–O–]2+

]–Co2+ + R• + HO•2.

RH

Decomposition of the co-coordinated ROOH introduces the main contribution to theinitiation of chains in the developed process:

]–Co2+ + n ROOH ]–Co2+...n ROOH

RO• + ]–[Co(OH)]2+ + (n –1) ROOH

kjk

K is the equilibrium constantInitiation rate is determined by the equation

wj D kjKŒROOHn0ŒCo2C0

1CKŒROOHn0: (8.5)

The main kinetic parameters of oxidation under the action of macrocomplexes aregiven in Table 8.11.

Because of the fact that a small increase in the parameter of oxidability(for non-catalytic oxidation of cyclohexene by oxygen at 303 K k2k

�1=26 D

2:3 L1=2=mol1=2 c1=2/ cannot provide formation of significant amounts of oxi-dation products, it is supposed that they are formed also as a result of a reaction oflinear chain termination with participation of fixed Co2C complexes.

The K value (>102 L=mol) and independence of wi on [ROOH] allow us to makethe important conclusion that high local concentration of hydroperoxide is creatednear the surface of the metal-containing polymeric catalyst. Transport of ROOHto the active centers is carried out as a result of its migration on the surface of a

Table 8.11 The kinetic parameters of cyclohexene oxidation in the presence of macromolecularmetal carboxylates

Catalyst

ŒCo2C �103 (g-atom/L)

wi � 106

(mol/L s)w � 104

(mol/L s)wŒCo2C�102 (s�1)

k2k�1=26

(L1=2=mol1=2

s1=2)

PE-gr-Co2CPAA 0.88 6.5 1.4 160.0 5.4Copolymer of

cobalt(II)acrylate withstyrene

10.00 2.8 0.97 9.7 5.8


100 300 500 7000

0.5

1.0

1.5

time, min

C C O

O

OH,

C C

C, mol / L

COOH

Fig. 8.22 The kinetics of cyclohexene oxidation with molecular O2 in the presence of metal-lopolymer catalyst based on copolymer of Ni(II) acrylate (64 mol%) and styrene. CNi D 4 mol=L,PO2 D 1 atm, 333 K

catalyst, and only after decomposition of ROOH the formed radicals leave into avolume where chain radical oxidation of cyclohexene develops [159].

The main problem in such processes is an essential increase in selectivity of areaction. The main product of oxidation of cyclohexene at presence of the copoly-mer of Ni2C acrylate and styrene [160] is cyclohexenylhydroperoxide, its content isabout 90% of total amount of products (Fig. 8.22). Besides cyclohexenylhydroper-oxide, slight amounts of cyclohexenone, cyclohexenole and cyclohexene oxide areformed. High selectivity of effect of Ni(II)-copolymers, is connected probably, withthe fact that process of generation of active centers is suppressed at the investigatedreaction conditions due to decomposition of hydroperoxide at participation of a tran-sition metal compound, as it was considered above, by the scheme of reactions (8.6).However, the final mechanism of such processes is not clear and, probably, requiresfurther research.

8.5.2 Reactions of Peroxidase Decomposition

Undoubtedly the diluted H2O2 solutions are ecologically profitable oxidizing agentsbesides atmospheric oxygen for large-scale processes. The traditional approach


to the estimation of their activity is the comparative study of the model reactionof disproportionation of hydrogen peroxide on homogeneous and heterogenizatedcomplexes. The general equation for the initial rate of disproportionation of hydro-gen peroxide includes rates of parallel processes of non-catalytic [on walls, in aliquid phase and on a surface of a polymer (Wo)] and catalytic decomposition (k isthe constant of its rate) on the metal ions:

W D Wo C kŒMnCŒH2O2: (8.6)

The contribution part of each of these processes into the total reaction rate ofdisproportionation of hydrogen peroxide at presence of the macromolecular metal-containing complex of Co2C polyacrylate [160] is presented below:

W � 103 (mol/L min)In homogeneous medium and on the wall of vessel 0.79On the surface of polymer 0.41With Co(II) polyacrylate 3.17

Catalytic activity of metal polyacrylates changed in the series: Co2C.3:45/ >

Cu2C .1:57/ > Mn2C.1:23/ > Fe3C.1:01/ > Cr3C.0:93/ > Ni2C (0.75) (values ofthe reaction rate are given in brackets, k�102, min�1). Comparative analysis of cat-alytic properties of polymeric metal-containing complexes with their low-molecularanalogues has shown that metal polyacrylates have stability of effect without lossof activity in repeated experiments (Fig. 8.23) and can be easily isolated from thereaction medium and used again.

00

10

20

30

40

5 10 15 20 25time, min

Con

vers

ion,

%

1

23

Fig. 8.23 Decomposition of H2O2 in the presence of Co(II) polyacrylate: first (1), second (2) andthird (3) cycles at 313 K, V D 20 ml, ŒH2O2 D 0:115 mol=L, mcat D 0:002g


Table 8.12 Decomposition of H2O2 in the presence of copolymers of Co(II) maleates and styrene(V D 20 mL, mcat D 0:002 g, 25ıC)

Co(II) hydromaleate (M1) – styrene Co(II) maleate (M1) – styrene

M1, mole fraction 0:20 0:38 0:59 0:33 0:44 0:52

k � 103 (min�1) 1:98 2:90 10:38 2:75 8:64 11:61

Ea (kcal/mol) 14:62 6:02

Catalytic activity of the copolymers of both maleate and hydromaleate of cobaltin the decomposition reaction of hydrogen peroxide grows with an increase in MCMpart in the copolymer (Table 8.12), rate constants of decomposition of hydrogenperoxide for the copolymer of cobalt maleate are higher in comparison with thecopolymer of hydromaleate salt.

Higher catalytic activity of the copolymers of cobalt maleate in comparison withCo(II) hydromaleate is confirmed also by the values of activation energy whichare equal: Ea D 6:02 kcal/mol for the copolymers of styrene and cobalt maleate(molar fraction of in the polymer is equal to 0.44) and Ea D 14:62 kcal/mol for thecopolymer of cobalt hydromaleate (molar fraction of MCM in the polymer is equalto 0.38).

Such distinction in properties of the complexes under consideration is connected,probably, with considerably distinguished ligand environment of a metal atom. As itwas shown in Chap. 4, the coordination polyhedron of cobalt in the molecule ofCo(II) maleate is a little bit distorted octahedron in which the acid residue is con-nected with the metal ion with the help of two oxygen atoms of both carboxyl groupsforming a chelated seven-membered cycle.

8.5.3 Other Catalytic Reactions

Polymerisation of vinyl monomers occurs efficiently under action of the initiator –copolymer of styrene with Na acrylate or MMA with Na methacrylate inaqueous solutions at 85ıC in absence of usual initiators [161]. It was of-fered [162] to use Zr methacrylate of general formula Zr4ŒOCOC.CH3/DCH210O2X2 � nH2O.X D OH�, CH2 D C.CH3/COO� etc.; n D 2; 4) as thecatalyst of block radical polymerization of vinyl monomers. Acyloxy-derivatives oftitanium, di- and tributoxytitanium butylmaleates TinOn�1.OCOCHDCHOCOC4H9/m.OC4H9/2nC2�m (n D 3, 5, 8; m D 1:5, 2.5, 3.0, 4.0, 6.0), arenor only epoxy hardeners, but they also improve apparently physical-mechanicalcharacteristics of the formed polymers [163, 164].

Na-salt of fumaric, maleinic and itaconic acids were investigated as the alterna-tive ecological catalysts of the etherification reaction of 1,2,3,4-bytene-tetracabonicacid and cellulose instead of traditionally used sodium hypophosphite at productionof fabrics [165].


The copolymer of styrene and porphyrin acrylate of Fe3C (the cytochrome modelP450) reveals higher catalytic activity in the hydroxylation reaction of cyclohexanein comparison with unfixed Fe3C porphyrin [166]:

H

C

O = C

O

N N

NNFe

Cl

H

C

x y

H2C CH2

It is supposed, that hydrophobic environment of the metal-containing porphyrinprevents formation of the inactive -oxo dimer owing to the polymeric chain.

Thus, it is possible to obtain purposefully metal-containing complex catalystsof various processes, varying a metal nature, ligand environment in a coordi-nation sphere of a metal and character of distribution of monomeric units ina metal-containing copolymeric chain. Polymerization and copolymerization ofmetal-containing monomers is the effective approach for the obtaining of the het-erogenizated metal-containing complex catalysts. The properties of such catalystscan be controlled by changing of a geometrical and configuration structure, of dis-tribution of metal-containing complexes in a chain while the traditional way ofimmobilized catalysts does not allow to affect on these factors. The tendency touse bimetallic catalysts containing metal atoms differing by catalytic functions wasnoted. Probably, the number of similar processes will increase, especially as syn-thetic opportunities allow us to design systems with controllable distances betweensuch centers.

References

1. A.R. Botsman, L.N. Fedorova, A.I. Vasilchenko, G.I. Dzhardimalieva, A.D. Pomogailo,Izv. Akad. Nauk. SSSR Ser. Khim. 576 (1992)

2. A.R. Botsman, L.V. Marchenko, Ukr. Khim. Zh. 52, 952 (1986)3. E.S. Rufino, E.E.C. Monteiro, Polymer 41, 4213 (2000)4. A. Gronowski, Z. Wojtczak, J. Thermal Anal. 26, 233 (1983)

References 253

5. Q. Lin, B. Yang, J. Li, X. Meng, J. Shen, Polymer 41, 8305 (2000)6. Y. Gao, F.R. Kogler, U. Schubert, J. Polym. Sci. A Polym. Chem. 43, 6586 (2005)7. G. Trimmel, P. Fratzl, U. Schubert, Chem. Mater. 12, 602 (2000)8. S. Willemin, B. Donnadien, L. Lecren, B. Henner, R. Clerac, C. Guerin, A.V. Pokrovskii,

J. Larionova, New J. Chem. 28, 919 (2004)9. A. Gronowoski, Acta Polymerica 41, 156 (1990)

10. K. Suchocka-Galas, J. Appl. Polym. Sci. 89, 55 (2003)11. T.K. Kwei, J. Polym. Sci. Polym. Lett. Ed. 22, 307 (1984)12. B. Chaturvedi, A.K. Srivastava, Indian J. Technol. 31, 851 (1993)13. M.A.J. van der Mee, R.M.A. I’Abee, G. Portale, J.G.P. Goosens, M. Van Duin, Macro-

molecules 41, 5493 (2008)14. H.-Q. Xie, W.-G. Yu, D. Xie, D.-T. Tian, J. Macromol. Sci. A Pure Appl. Chem. 44, 849

(2007)15. M.E.L. Wouters, V.M. Litvinov, F.L. Binsbergen, J.G.P. Goossens, M. Van Duin,

H.G. Dikland, Macromolecules 36, 1147 (2003)16. J.M. Willis, B.D. Favis, Polym. Eng. Sci. 28, 1416 (1988)17. W. Sinthavathavorn, M. Nithitanakul, B.P. Grady, R Magaraphan, Polym. Bull. 63, 23 (2009)18. W. Sinthavathavorn, M. Nithitanakul, B.P. Grady, R. Magaraphan, Polym. Bull. 61, 331

(2008)19. W. Sinthavathavorn, M. Nithitanakul, R. Magaraphan, B.P. Grady, J. Appl. Polym. Sci. 107,

3090 (2007)20. A. Valenza, G. Spadaro, D. Acierno, Colloid Polym. Sci. 278, 986 (2000)21. V. Caldas, G.R. Brown, J.M. Willis, Macromolecules 23, 338 (1990)22. K. Cho, H.K. Jeon, T.J. Moon, J. Mater. Sci. 28, 6650 (1993)23. J. Horrion, P.K. Agarwal, Polym. Commun. 30, 264 (1989)24. G. Fairley, R.E. Prud’homme, Polym. Eng. Sci. 27, 1495 (1987)25. X. Yuan, Z. Peng, Y. Zhang, Y. Zhang, J. Appl. Polym. Sci. 77, 2740 (2000)26. A. Du, Z. Peng, Y. Zhang, Y. Zhang, J. Appl. Polym. Sci. 93, 2379 (2004)27. A. Du, Z. Peng, Y. Zhang, Y. Zhang, J. Polym. Sci. Polym. Phys. B 42, 1715 (2004)28. H. Szalinska, M. Pietrzak, G. Janowska, Radiat. Phys. Chem. 27, 101 (1986)29. N. Nagata, T. Sato, T. Fujii, Y. Saito, J. Appl. Polym. Sci. 53, 103 (1994)30. R. Costin, W. Nagel, R. Ekwall, Rubber Chem. Technol. 64, 152 (1991)31. A. Dontsov, E.F. Rossi, A.F. Martelli, Eur. Polym. J. 8, 351 (1971)32. X. Yuan, Z. Peng, Y. Zhang, Y. Zhang, Polym. Comp. 7, 431 (1999)33. Z. Peng, X. Liang, Y. Zhang, Y. Zhang, J. Appl. Polym. Sci. 84, 1339 (2002)34. X. Yuang, Y. Zhang, Z. Peng, Y. Zhang, J. Appl. Polym. Sci. 84, 1403 (2002)35. R.C. Klingerden, M. Oyama, Y. Saito, Rubber World 202, 26 (1990)36. A. Du, Z. Peng, Y. Zhang, Y. Zhang, J. Appl. Polym. Sci. 89, 2192 (2003)37. T. Ikeda, B. Yamada: J. Appl. Polym. Sci. 74, 1499 (1999)38. T. Ikeda, S. Sakurai, K. Nakano, B. Yamada, T. Okamoto, J. Soc. Rubber Ind. Jpn. 69, 423

(1996)39. T. Ikeda, S. Sakurai, K. Nakano, B. Yamada, J. Appl. Polym. Sci. 59, 781 (1996)40. S.M. Sayyah, A.A. Bahgat, A.I. Sabby, F.I.A. Said, S.H. El-Hamouly, Acta Polymerica 39,

399 (1988)41. E.S.M. Higgy, S.M. Sayyah, I.H. Rashed, E. El-Mamoun, A.M. Hussein, Acta Polymerica

37, 606 (1984)42. S.M. Sayyah, M.A. Khaled, A.I. Sabry, I. A. Sabbah, Acta Polymerica 40, 293 (1989)43. Pat. USA 4429094, 198144. Japan appl. 60-181107, 198445. Japan appl. 58-185641, 198246. Japan appl. 54-95695 197847. N.V. Petrochenkova, B.V. Bukvetskii, A.G. Mirochnik, V.E. Karasev, Koord. Khim. 28, 67

(2002)48. A.G. Mirochnik, N.V. Petrochenkova, V.E. Karasev, Vysokomol. Soedin. A 41, 1642 (1999)


49. M.V. Petukhova, N.V. Petrochenkova, A.G. Mirochnik, V.E. Karasev, E.F. Radaev:Vysokomol. Soedin. B 44, 1267 (2002)

50. N.V. Petrochenkova, M.V. Petukhova, A.G. Mirochnik, V.E. Karasev, Koord. Khim. 27, 717(2001)

51. Q.D. Ling, Q.J. Cai, E.T. Kang, K.G. Neoh, F.R. Zhu, W. Huang, J. Mater. Chem. 14, 2741(2004)

52. Q. Ling, M. Yang, Z. Wu, X. Zhang, L. Wang, W. Zhang, Polymer 42, 4605 (2001)53. C. Du, L. Ma, Y. Xu, Y.Y. Zhao, C. Jiang, Eur. Polymer J. 34, 23 (1998)54. C. Du, Y. Xu, L. Ma, W.L. Li, J. Alloys Comp. 265, 81 (1998)55. W.-Y. Xu, Y.-S. Wang, D.-G. Zheng, S.-L. Xia, J. Macromol. Sci. Chem. A 25, 1397 (1988)56. V.A. Smirnov, G.A. Sukhodol’skii, O.E. Filippova, A.R. Khokhlov, Zh. Fiz. Khim. 72, 710

(1998)57. I. Nagato, R. Li, E. Banks, Y. Okamoto, Macromolecules 16, 903 (1983)58. Y. Okamoto, J. Kido, H.G. Brittain, S. Paoletti: J. Macromol. Sci. Chem. A 1385 (1988)59. A.G. Mirochnik, N.V. Petrochenkova, V.E. Karasev, Zh. Fiz. Khim. 75, 1808 (2001)60. W.L. Li, T. Mishima, G.Y. Adachi, X. Shiokawa, J. Inorg. Chim. Acta. 121, 93 (1986)61. K.D. Matthews, S.A. Bailey-Folkes, I.A. Kahwa, J. Phys. Chem. 96 7021 (1992)62. J.-C.G. Bunzli, P. Froidevaux, J.M. Harrowfield, Inorg. Chem. 32, 3306 (1993)63. M.R. Robinson, M.B. O’Regan, G.C. Bazan, Chem. Commun. 17, 1645 (2000)64. M. Sun, H. Xin, K.Z. Wang, Y.A. Zhang, L.P. Jin, C.H. Huang, Chem. Commun. 702 (2003)65. A.G. Mirochnik, N.V. Petrochenkova, V.E. Karasev, Izv. Akad. Nauk. SSSR Ser. Khim. 2007,

1993, 1559 (1996)66. E.L. Koryagina, V.P. Arkhireev, T.A. bolkova, Plast. Massy 8, 41 (2003)67. E. A. Gonyukh, E.V. Kuznetsov, V.P. Prokop’ev, Izv. VUZ’ov. Khimiya i Khim. Tekhnol. 27,

367 (1984)68. V.N. Serova, O.P. Shmakova, V.V. Chirkov, V.I. Morozov, V.P. Arkhireev, Vysokomol. Soedin.

A 41, 970 (1999)69. Japan appl. 59-217705, 198370. Pat. CIIIA 4473073, 198371. I. Ogawa, H. Yamano, K. Miyogawa, J. Appl. Polym. Sci. 47, 217 (1993)72. T.G. Nunes, G. Guillot, J.M. Bordado, Polymer 41, 4643 (2000)73. W.-F. Lee, P.-L. Yen, J. Appl. Polym. Sci. 64, 2371 (1997)74. W.-F. Lee, P.-L. Yen, J. Appl. Polym. Sci. 66, 499 (1997)75. Y.M. Mohan, P.S.K. Murthy, B. Sreedhar, K.M. Raju, J. Appl. Polym. Sci. 102, 1 (2006)76. G.L. Elyashevich, N.G. Belnikevich, S.A. Vesnebolotskaya, Vysokomol. Soedin. 51, 809

(2009)77. W. Ren, Z. Peng, Y. Zhang, Y. Zhang, J. Appl. Polym. Sci. 92, 1804 (2004)78. R. Weiging, W. Xianogong, L. Yanqing, H. Yuli, N. Aijie, J. Appl. Polym. Sci. 101, 1181

(2006)79. W.F. Lee, C.-H. Hsu, J. Appl. Polym. Sci. 69, 229 (1998)80. W.F. Lee, R.-J. Wu, J. Appl. Polym. Sci. 64, 1702 (1997)81. W.F. Lee, R.-J. Wu, J. Appl. Polym. Sci. 62, 1099 (1996)82. C. Slusarczyk, A. Wlochowicz, A. Gronowski, Z. Wojtczak, Polymer 29, 1581 (1988)83. Japan appl. 59-1871284. F. Santiago, A.E. Mucientes, M. Osorio, C. Rivera, Eur. Polym. J. 43, 1 (2007)85. F. Santiago, A.E. Mucientes, M. Osorio, F.J. Poblete, Polym. Int. 55, 843 (2006)86. Y. Zheng, A. Wang, J. Appl. Polym. Sci. 108, 211 (2008)87. A. Pourjavadi, H. Ghasemzaden, R. Soleyman, J. Appl. Polym. Sci. 105, 2631 (2007)88. W. Tao, W. Xiaoqing, Y. Yi, H. Wenqiong, Polym. Int. 55, 1413 (2006)89. L. Song, M. Zhu, Y. Chen, K. Haraguchi, Macromol. Chem. Phys. 209, 1564 (2008)90. C.L. Bell, N.A. Peppas, Adv. Polym. Sci. 122, 125 (1995)91. G. Bai, A. Suzuki, Eur. Phys. J E Soft Matter. 14, 107 (2004)92. Y. Hirashima, H. Tamanishi, H. Sato, K. Saito, A. Naito, A. Suzuki, J. Polym. Sci. B Polym.

Phys. 42, 1090 (2004)93. Y. Hirashima, A. Suzuki, J. Phys. Soc. Jpn. 73, 404 (2004)

References 255

94. Y. Hirokawa, T. Tanaka, J. Chem. Phys. 81, 6379 (1984)95. Y. Liu, J.L. Velada, M.B. Huglin, Polymer 40, 4299 (1999)96. T. Harada, Y. Hirashima, A. Suzuki, M. Goto, E. Mafune, M. Tokita, Polymer Prepr. Jpn. 51,

3316 (2002)97. H. Sato, Y. Hirashima, M. Goto, M. Tokita, J. Polym. Sci. B Polym. Phys. 43, 753 (2005)98. M. Kubo, T. Matsuura, H. Morimoto, T. Uno, T. Iton, J. Polym. Sci. A Polym. Chem. 43,

5032 (2005)99. J.L. Velada, Y. Liu, M.B. Huglin, Macromol. Chem. Phys. 199, 1127 (1998)

100. S. Yarimkaya, H. Basan, J. Macromol. Sci. A Pure Appl. Chem. 44, 699 (2007)101. S. Yarimkaya, H. Basan, J. Macromol. Sci. A Pure Appl. Chem. 44, 939 (2007)102. M.T.A. Ende, N.A. Peppas, J. Appl. Polym. Sci. 59, 673 (1996)103. W.-F. Lee, R.-J. Wu, J. Appl. Polym. Sci. 62, 1099 (1996)104. W.-F. Lee, R.-J. Wu, J. Appl. Polym. Sci. 81, 1360 (2001)105. W.-F. Lee, C.-H. Shieh, J. Appl. Polym. Sci. 73, 1955 (1999)106. K. Sreenivasan, J. Appl. Polym. Sci. 83, 2184 (2002)107. J.-S. Yang, G.-H. Hsiue, J. Memb. Sci. 126, 139 (1997)108. E. Tsuchida, H. Nishide, M. Ohyanagi, H. Kawakami, Macromolecules 20, 1907 (1987)109. G.-H. Hsiue, J.-M. Yang, J. Polym. Sci. Polym. Chem. Ed. 31, 1457 (1993)110. N. Nishide, H. Kawakami, Y. Sasame, K. Ishiwata, E. Tsuchida, J. Polym. Sci. Polym. Chem.

Ed. 30, 77 (1992)111. K. Inui, T. Noguchi, T. Miyata, T. Uragami, J. Appl. Polym. Sci. 71, 233 (1999)112. A. Dupont, A. Vidonne, P. Fievet, A. Foissy, Water Res. 40, 1303 (2006)113. B. Molinari, P. Argurio, T. Poerio, Desalination 162, 217 (2004)114. B.L. Rivas, S.A. Pooley, M. Luna, K.E. Geckeler, J. Appl. Polym. Sci. 82, 22 (2001)115. A. Nastasovi, S. Jovanovic, D. Dordevic, A. Onjia, D. Jakovljevi, T. Novakovic, React. Funct.

Polym. 58, 139 (2004)116. A.E. Ali, H.A. Shawki, H.A.A. Rehim, E.A. Hegazy, Eur. Polym. J. 39, 2337 (2003)117. H.A. Essawy, H.S. Ibrahim, React. Funct. Polym. 61, 421 (2004)118. B.L. Rivas, S. Villegas, B. Ruf, J. Appl. Polym. Sci. 99, 3266 (2006)119. O.G. Marambio, G.D. Pizarro, M. Jeria-Orell, M. Huerta, C. Olea-Azar, W.D. Habicher,

J. Polym. Sci. Polym. Chem. 43, 4933 (2005)120. R. Cokun, C. Soykan, M. Sacak, React. Funct. Polym. 66, 599 (2006)121. R. Cokun, C. Soykan, A. Deliba, Eur. Polym. J. 42, 625 (2006)122. S. Cavus, G. Gurdag, Polym. Adv. Technol. DOI: 10.1002/pat. 1113 (2008)123. G. Guclu, G. Gurdag, S. Ozgumus, J. Appl. Polym. Sci. 90, 2034 (2003)124. G. Guclu, G. Gurdag, S. Ozgumus, J. Appl. Polym. Sci. 90, 2034 (2003)125. S. Cavus, G. Gurdag, M. Yasar, K. Guclu, M.A. Gurkaynak, Polym. Bull. 57, 445 (2006)126. S.P. Bajpai, S. Johnson, J. Macromol. Sci. A Pure Appl. Chem. 44, 285 (2007)127. S.P. Bajpai, S. Johnson, Speculations Sci. Technol. 42, 1049 (2007)128. F. Urena-Munez, P. Diaz-Jimenez, C. Barrera-Diaz, M. Romero-Romo, M. Palomar-Pardave,

Radiat. Phys. Chem. 68, 819 (2003)129. Z. Su, X. Lu, X. Chang, J. Appl. Polym. Sci. 71, 819 (1999)130. G. Wulff, Angew. Chem. Int. Ed. Engl. 34, 1812 (1995)131. J. Steinke, D.C. Sherrinton, I.R. Dunkin, Adv. Polym. Sci. 123, 81 (1995)132. A.A. Efendiev, V.A. Kabanov, Pure Appl. Chem. 54, 2077 (1982)133. C. Alvarez-Lorenzo, O. Guney, T. Oya, Y. Sakai, M. Kobayashi, T. Enoki, Y. Takeoka,

T. Ishibashi, K. Kuroda, K. Tanaka, G. Wang, A.Yu. Grosberg, S. Masamune, T. Tanaka,J. Phys. Chem. 114, 2812 (2001)

134. K. Sreenivasan, J. Appl. Polym. Sci. 14, 2795 (2001)135. W. Kuchen, J. Schram, Angew. Chem. Int. Ed. Engl. 27, 1695 (1988)136. A.D. Pomogailo, N.P. Arkhipov, T.S. Meshalkin, G.I. Dzhardimalieva, A.M. Bochkin,

N.M. Bravaya, N.A. Bakunov, Dokl. Akad. Nauk. 335, 749 (1994)137. G.I. Dzhardimalieva, A.D. Pomogailo, Izv. Akad. Nauk SSSR Ser. Khim. 352 (1991)138. A.H. Dam, D. Kim, J. Appl. Polym. Sci. 108, 14 (2008)139. G.D. Saunders, S.P. Foxon, P.H. Walton, M.J. Joyce, S.N. Port, Chem. Commun. 273 (2000)


140. D. Solpan, O. Guven, J. Macromol. Sci. A Pure Appl. Chem. 42, 485 (2005)141. D. Saraydin, D. Solpan, Y. Isikver, O. Guven, J. Macromol. Sci. A Pure Appl. Chem. 39, 969

(2002)142. E. Karadag, D. Saraydin, O. Guven, Sep. Sci. Technol. 30, 3747 (1995)143. A.D. Pomogailo, Catalysis by Immobilizide Complexes (Nauka, Moscow, 1991)144. D. Wohrle, A.D. Pomogailo, Metal Complexes and Metals in Macromolecules (Wiley-VCH,

2003)145. A.D. Pomogailo, Kinet. Catal. 45, 67 (2004)146. A.D. Pomogailo, Vysokomol. Soedin. A 50, 2090 (2008)147. D. Wohrle, A. Pomogailo. in Advanced Functional Molecules and Polymers, vol. 1, ed. by

H.S. Nalva (Gordon & Breach Sci. Publ., New York, 2001), p. 87148. D.C. Sherrington, A.P. Kubett (eds.), Supported Catalysts and their Applications (Royal Soc.

Chem., Cambridge, 2001)149. P. Mastrorilli, C.F. Nobile, Coord. Chem. Rev. 248, 377 (2004)150. Z. Wang, G. Chen, K. Ding, Chem. Rev. 109, 322151. W. Mori, S. Takamizawa, C.N. Kato, T. Ohmura, T. Sato, Microporous Mesoporous Mater.

73, 31 (2004)152. S. Naito, T. Tanibe, E. Saito, T. Miyao, W. Mori, Chem. Lett. 30, 1178 (2001)153. T. Sato, W. Mori, C.N. Kato, T. Ohmura, K. Yokoyama, S. Takamizawa, S. Naito, Chem. Lett.

32, 854 (2003)154. T. Sato, W. Mori, C.N. Kato, E. Yanaoka, T. Kuribayashi, R. Ohtera, Y. Shiraishi, J. Catal.

232, 186 (2005)155. W. Mori, T. Sato, T. Ohmura, C.N. Kato, T. Takei, J. Solid State Chem. 178, 2555 (2005)156. S.-H. Chen, Chin. J. Chem. 17, 309 (1999)157. A.V. Nikitin, A.D. Pomogailo, V.L. Rubailo, Izv. Akad. Nauk. SSSR Ser. Khim. 36 (1987)158. A.V. Nikitin, A.D. Pomogailo, S.A. Maslov, V.L. Rubailo, Neftekhimiya 27, 234 (1987)159. S.N. Kholuiskaya, A.D. Pomogailo, N.M. Bravaya, S.I. Pomogailo, V.A. Maksakov, Kinetika

i Katalysis 44, 831 (2003)160. G.I. Dzhardimalieva, A.D. Pomogailo, Kinetika i Katalysis 39, 893 (1998161. T. Ouchi, M. Uneba, K. Tadano, M. Imoto, J. Polym. Sci. Polym. Chem. Ed. 20, 2089 (1982)162. Appl. Germany, 3137840, 1981.163. L.D. Dultseva, A.L. Suvorov, N.Yu. Ostanina, Yu.V. shatrova, A.I. Suvorova. Plast. Massy 17

(2002)164. A.B. Burdina, A.L. Suvorov, L.L. Burdina, L.D. Dultseva, T.G. Khonina, V.V. Sennikov. Plast.

Massy 34 (2001)165. H.M. Choi, C.M. Welch, Textile Chem. Color 26, 23 (1994)166. H. Yu, X. Chen, X. Li, J. Huang, L. Ji, Front. Chem. Eng. China 1, 65 (2007)

Chapter 9Monomeric and Polymeric Metal Carboxylatesas Precursors of Nanocomposite Materials

The interest in the metal-containing polymeric nanocomposites is caused by a uniquecombination of properties of metals nanoparticles, their oxides and chalcogenides,and by mechanical, film-forming and other characteristics of polymers with oppor-tunities for their use as magnetic materials for record and storage of information,as catalysts and sensors, in medicine and biology [1]. Homo- and copolymers ofacrylic and methacrylic acids and their salts are widely used for the stabilization ofmetal-containing dispersions. For example, nanocomposites of the PbS/copolymerof styrene-methacrylic acid [2], PbS/copolymer of ethylene-methacrylic acid [3],CuS/polyvinylalcohol-polyacrylicacid [4],Cu2C-polyacrylicacid/CdS[5],Co/PAA-block-PS[6]wereobtainedbyvariousmethods.HeterometallicZnS/CdSnanocrystalswith luminescent properties were synthesized by the treatment of the triple copolymerof styrene-Zn diacrylate-Cd diacrylate by the general reagent H2S (MnD 4:7�104,atomic ratio Zn=CdD 3:3 W 1) [7]. Such examples are very numerous. On the onehand, carboxylated compounds of a monomeric and polymeric structure can bemolecular precursors of nanocomposite materials. On the other hand, carboxylgroups of macroligands are efficient stabilizers of nanoparticles; these functions arefrequently developed together in one system. Amphiphilic character of carboxylatedpolymers and copolymers allows not only to encapsulate nanoparticles of metalsor to combine them with polymeric and inorganic matrixes or biological objects,but also allows to give such properties as solubility in various mediums, ability toself-organization, etc., to nanoparticles.

9.1 Formation and Stabilization of Nanoparticles at Presenceof Macroligands with Carboxyl Functional Groups

Aggregative stability of particles in a polymeric matrix is defined by the processes ofsteric stabilization, flocculation, phase division, electrostatic interactions, etc. It wasshown by AFM researches [8], that Van der Waals attraction forces act between twouncovered polymer surfaces of the yttrium-stabilized zirconyl (YSZ) nanoparticlesat distance up to 200 nm, causing their aggregation. At the same time, the presenceof an adsorbed layer of ammonium polyacrylate or polymethacrylate on the surface


257

258 9 Monomeric and Polymeric Metal Carboxylates as Precursors

of YSZ nanoparticles results in the occurrence of the repulsive forces between themat 35 nm distance between surfaces. At that, ammonium polymethacrylate providesstronger repulsion (4 nN at a distance of 25 nm), than ammonium polyacrylate, that,probably, is caused by an additional steric barrier due to CH3-group. Conformationeffects of a polymeric chain are especially sensitive to the reaction conditions, forexample, pH. So, radiation-chemical reduction of the AgC ions in aqueous weakalkaline solutions is accompanied by their coloration into blue color in the presenceof PAA [9–11]. In an alkaline solution, PAA molecules are unfolded into chainsdue to repulsion of COO-groups, and AgC ions receive an opportunity to interactwith COO-groups. The formed “blue silver” has high stability even in air and canbe isolated in a pure form at water evaporation. Sizes of the Co nanoparticles duringhigh-temperature reduction of Co2C in the presence of the polymeric surfactant ofPAA-block-PS were controlled by the [Co2C]/[COOH] change or by the length ofthe PS block unit, by content of the co-surfactant and reaction time [6]. Concen-tration of PAA influenced essentially on the morphology of the Ag nanoparticles:dendritic Ag particles with the 400–500 nm diameter were formed at 0.1 mass%content of the polymer [12]. An increase in the PAA concentration up to 0.5 mass%resulted in the formation of the Ag particles of mainly spherical form (particle size is160–200 nm). Spherical Cu nanoparticles were also obtained in the PAA-Cu2C filmsby the reduction in the H2 atmosphere at temperatures higher than 220ıC [13]. It isinteresting that such nanocomposite films were less stable and Cu particles weresubjected to the oxidation to Cu2C during several weeks, while reduction at temper-atures higher than 230ıC was accompanied by the occurrence of keto-groups dueto condensation of carboxyl groups and formation of the cross-links between PAAchains that provided higher stability of the formed Cu nanoparticles.

As a whole, interactions of polymeric chains with a nanoparticle are various,they are differed by the nature and intensity and are frequently revealed simultane-ously. Polymeric chains can form covalent1 [14–18], ionic or coordination bondswith the atoms of a surface layer of a metal at chemical adsorption. So, stabiliza-tion of silver nanoparticles in the presence of liquid-crystalline polymers containingcyanobiphenylic mesogenic groups and units of acrylic acid is carried out due tointeraction of a macromolecule with a surface of a nanoparticle with the formationof various types of bonds (Fig. 9.1) [19].

It is interesting that stable dispersions of nanoparticles can also be obtainedin monomeric acids or solutions of their salts. Deprotonated carboxylated groups(1,547, 1;437 cm�1) were revealed in the IR spectrum of ZnS:Mn nanoparticles iso-lated from their dispersions in acrylic acid and stable till 8 months [20].

1 Recently, researchers more often turn to this type of bond at design of nanomaterials frommolecular blocks [14–17]. With this purpose, nanoparticles are additionally functionalized, in-cluding functionalization by carboxyl groups, for their subsequent covalent linkage with othercomponents. Alkane-thiolate-protected nanoparticle of gold, supplied with a carboxyl group, wascovalently joined by such principle to the polylysine molecule with the formation of the conjugateof polymer-nanoparticles in the form of rings, loops, cycles, etc. [18].

9.1 Formation and Stabilization of Nanoparticles 259

Ag

4

1

2

3

Ag

Ag

C ≡ NO

O C ≡ N:-

HO

Oδ −

δ+

Fig. 9.1 Scheme of the interaction of liquid crystalline polymer molecule with the surface of silvernanoparticle: (1) silver nanoparticle, (2) a mesogenic group, (3) polymer chain, (4) a carboxylicgroup

Interaction of carboxylated ligands with a surface of nanoparticles of titanium(IV) oxide was investigated with the use of the probe molecule of all-trans-retinoicacid [21]. Information about various forms of superficial bonds can be received fromthe excited triplet state of an acid molecule at photoinduction of recombination ofa charge of an adsorbed superficial monomolecular layer [22]. It was shown, thatthe character of bonds of carboxyl groups with nanoparticles of titanium (IV) ox-ide depends on their sizes. At the reduction of the nanoparticles sizes from 6 nmto <1:4 nm physical adsorption decreases while part of chemical adsorption (mon-odentate, bridging, chelate coordination) grows (Scheme 9.1).

Ti

OO

Ti

R

OO

Ti

R

Ti

OO

Ti

R

OO

R

Ti

Scheme 9.1 The type of bonds of carboxyl groups with nanoparticles of titanium (IV) oxide

Dimensional effect in this case is connected with the fact that superficial atomsof particles have various coordination conditions that can result in an increasein number of coordinated unsaturated defective places at transition to nanolevel.Just strong coordination of ’-Se colloid particles in a film of polyacrylic acid doesnot give an opportunity of the oriented growth of crystalline selenium nanowires,while in not coordinating (PS, polydimethyl siloxane) or weakly coordinating[poly(©-caprolactam)] polymeric films it is possible to obtain required lateral-oriented Se nanowires on a surface of a substrate [23].

Stabilization of silver particles including intermediate clusters of AgmCn [24, 25]

by sodium polyacrylate with various degree of polymerization (97;000 < Mw <


Fig. 9.2 Molar mass of theNaPAA vs. the ratio[AgC]/[COO�] in the Agnanoparticle formation atsodium polyacrylateconcentration of 0.06 g/L.Symbols (1) denote particleformation and (2) particleformation not observed

650;000) can be an example of specific interaction of a polymer with a nanoparticle.By the methods of static laser light scattering (LLS) and UV-VIS-spectroscopy itwas shown, that formation of Ag nanoparticles under UV-irradiation of AgC ions(one AgC ion per 100 COO–groups) in the presence of PAA-Na (0.06 g/L) occursonly when Mw of the polymer exceeds 149,000 [26]. At that it is important to note,that concentration of AgC, necessary for the formation of Ag nanoparticles in thesystem with PAA-Na (Mw D 453;000), is almost two times more than AgC concen-tration used in case of the PAA-Na sample with Mw D 650;000. It testifies that theformation of silver nanoparticles occurs at some critical concentration of Ag ionsdepending on molecular weight of Na polyacrylate (Fig. 9.2). High local concen-tration of AgC ions necessary for the nucleation is reached only at fixed molecularweight of a polymer and a ball size.

Medium pH influences essentially on the method of interaction of carboxylatedgroups of polymers with nanoparticles. In the composite “PAA/modified nanoparti-cles of silica gel” [27]

Silica

N

OHOH

HOOH

at pH 2.5–5.3 complex formation between components is carried out, basically dueto ionic interactions; in the strong-acidic medium (pH < 2:3) nitrogen atoms are pro-tonated by HCl instead of carboxyl group of PAA, and an ionic complex dissociates.At pH 5.8–8.0, PAA is partly ionized and hydrogen bonds between carboxylic andhydroxyl groups become prevalent (Scheme 9.2).

On the contrary, occurrence of charged PAA chains in the strong-alkalinemedium (pH > 8:5), when each charged group of a polyelectrolyte is in theneighborhood with a counter-ion, results in the break of hydrogen bonds. It istypical, that pH-induced changes of the nature of specific intermolecular interac-tions are accompanied by the transition of a colloid system from a transparentform in the strong-acidic medium to a lactic dispersion at pH� 3:5 and again toa transparent solution at high pH values. We shall note, that just temperature and

9.1 Formation and Stabilization of Nanoparticles 261

Scheme 9.2 The type of complexes of carboxylic polymers with nanoparticles depending on pH

medium pH are the most attractive for biomedical purposes among many externalinfluences (temperature, a solvent, light, pressure, ionic strength of medium, etc.)causing sensitive response of the so-called smart polymeric hydrogels. Heat-and pH-sensitive nanocomposite was synthesized in situ by radical polymeriza-tion of N -isopropylacrylamide (NIPA) in the presence of the synthetic hectoriteŒMg5:34Li0:66Si8O20.OH/4�Na0:66 and linear polyacrylic acid [28]. The obtainedhydrogels had a structure of a semi-interpenetrating organic-inorganic networkand showed ability to change repeatedly their volume in response to the changingconditions (Fig. 9.3).

It is important, that PAAm-(hectorite)n-NIPA (m=n D 2:5–3) show sufficientlyhigh mechanical properties at the optimal composition.

New opportunities are opened at the creation of the materials on the basis ofhydrophobic-modified polymeric acids [29]. Octylamine [30, 31]- or dodecylamine[32]-modified polyacrylic acid is widely used for the encapsulation of nanocrys-talline quantum dots (NQds), giving them high water solubility. Diblock copolymerof poly(styrene)-block-poly(acrylic) acid show the same effect in its adducts withcarbon nanotubes; the obtained nanocomposites have good solubility in variousmediums [33]. In all these cases, an amphiphilic polymer surrounds a nanoparticleforming a micellar layer around it. Using this methodology, it is possible to enter theformed NQds-polymeric complex into an inorganic matrix, for example, TiO2 [31],or to form layered nanostructures on various surfaces. One of these methods wasoffered in the work [34]. It is based on the ability of the CdS nanoparticles, cappedby the polyacrylate-anion, to self-organization into layered ensembles with cationicpoly(diallyldimethylammonium chloride) on a surface of solid substrates of siliconor quartz (Fig. 9.4).

It is remarkable that Coulomb repulsions of the surface charges, arising afterfull compensation of the positive charges of a cationic polyelectrolyte by PAA-CdS


1.2

a

b

0.9

20°C40°C

pH7pH2

0.6

0.3

0–12 0 12 24 36

Time (hr)

48 60 72

1.2

1

0.8

0.6

0.4–12 0 12 24 36 48 60 72

Wge

l(t)/

Wge

l (eq

s)

Time (hr)

Wge

l(t)/

Wge

l (eq

s)

Fig. 9.3 Swelling behavior (wgel(t)/wgel(eqs)) of NIPA-hectorite-PAA nanocomposite gel vs.temperature (a) and pH (b) in cyclic experiments

–––– –

– – – – – – – – – – –

––

++ + +

++

++ +

+

++

++

++

++

+

+ ++

––

–––

––––

–––

––

––

–––

––

Fig. 9.4 A model of layered assemble of the PAA-CdS nanoparticles embedded intopoly(diallyldimethylammonium chloride) cationic polyelectrolyte

anions, promote formation of only monomolecular layer of nanoparticles in eachact of deposition. An opportunity of synthesis of the similar type of interpolyelec-trolytic complexes including metal particles was shown in a lot of research (see, forexample [35]). It is emphasized, that interhelium interactions in such reactions havethe electrostatic nature.

Questions of the effective stabilization and modification of nanoparticles areclosely interdependent with the development of their obtaining methods.

9.2 Basic Obtaining Methods of Metal-Containing Polymeric Nanocomposites 263

9.2 Basic Obtaining Methods of Metal-Containing PolymericNanocomposites on the Basis of Monomeric and PolymericCarboxylates

All known obtaining methods of the considered type of nanocomposites are reducedto the so-called bottom up synthesis, since nanoparticles in the nanocomposites arecreated from separate atoms. The primary majority of physical-chemical methods of“assembly” of nanoparticles give an opportunity to control the size and compositionof nanoparticles and to obtain nanoparticles with sufficiently narrow size distribu-tion. It is a complicated problem for, for example, alternative methods (top-down) –grinding and dispersion.

9.2.1 Thermal Conversions of Metal-Containing CarboxylatedPrecursors

One of the perspective obtaining methods of metal-containing nanoparticles andtheir polymeric composites are thermal conversions of metal-containing monomers.It is possible to combine in situ formation of superfine metal particles and astabilizing them polymeric matrix during these thermal conversions [36–40]. Metal-containing polymeric nanocomposites on the basis of acrylates of Cu(II) [36], Co(II)[41, 42], Fe(III) [43], Ni(II) [44], their cocrystallizates [45] and also maleates ofCo(II) [46] and Fe(III) [47] were obtained using such an approach. Microstructureof the formed composites is represented by the metal-containing nanoparticles of5–30 nm diameter and close to spherical form, they are dispersed homogeneouslyin the polymeric matrix with average distance 10–12 nm [48] (Fig. 9.5). Uniformity

Fig. 9.5 TEM microphotograph (a) and diagram of nanoparticles distribution on the size (b) forthe products of thermolysis of Co(II) acrylate at 643 K


Fig. 9.6 Distributionof metal-containingnanoparticles on the size.The products of thermolysisof metal carboxylates:(1) Fe(III) acrylate;(2) Fe.HCOO/2 � 2H2O;(3) Co(II) maleate

0.3

0.2

3

12

0.1

0 8 16 24 32 40d, nm

Nd / ∑Nd

of distribution of the metal-containing particles in the matrix and their narrow sizesdistribution, testifies, apparently, a big degree of homogeneity of processes of de-carboxylation and formation of a new phase. It is important to note, that the averagesize of the particles, formed during thermal conversions of unsaturated metal car-boxylates, is lower than for the products of thermal conversions of saturated metalcarboxylates (Fig. 9.6) [49].

Systematic research of thermolysis of unsaturated metal carboxylates allowed toreveal community of character of their conversions, consisting in sequences of threebasic macrostages [36, 41, 43, 44, 50]:

1. Dehydration of crystalline hydrates of monomers (Tterm < 423 K) with simulta-neous reorganization of ligand environment, accompanying by separation of apart of carboxylated ligands.

2. Solid-phase polymerization of the reorganized dehydrated monomer (Tterm

� 453–493 K).3. Decarboxylation of the formed (co)polymer at high temperatures (Tterm > 473 K).

Main gas evolution and mass loss of a sample at thermolysis are connected withthe last process.

It is possible to estimate thermal stability of metal carboxylates by the relativestrength of interatomic M–O and C–O bonds in their crystal-chemical structure.Lengths of M–O and C–O bonds within the limits of a coordination polyhedroncan be essentially differed, that testifies their energy nonequivalence. Dentate abil-ity of the fixed part of unsaturated ligands can be changed during dehydration and,similar to anhydrous carboxylates of saturated acids, [51] they start to carry outsimultaneously both the role of a ligand and function of a lacking solvate in acrystalline structure. An increase in dentate ability of ligands results in distortionof oxygen surrounding of a metal with the respective change of M–O and C–Odistances in the structure and, hence, in change of their strength. In particular, depen-dence of the fragment CH2DCHCOO– ions yield vs. the electric field intensity inmass-spectrometric research at fragmentation of the ŒFe3O.CH2DCHCOO/6�C ion


Fig. 9.7 Mass spectra of the positive ions from aqua-alcohol solution of Fe(III) oxoacrylate atU D 200 V (a) and 400 V (b)

indicates [52] energy nonequivalence of the M–OOCCHDCH2 bonds in the Fe(III)oxoacrylate. In the mass spectrum at U D 400 V (Fig. 9.7), ions with m=z D 539,468, 397 correspond to the separation of one, two and three CH2DCHCOO-groups,and the ion with m=z D 341 corresponds to the separation of Fe.CH2DCHCOO/3

molecule from the molecular ŒFe3O.CH2DCHCOO/6�C ion.During the study of the acidic maleates of the M.C4H3O4/2� 4H2O composition

(M D Mn, Fe, Co, Ni), dependence between structural and thermal characteris-tics of these connections was determined: with reduction of an ionic radius fromMn(II) cation to Ni(II) cation there is a reduction of interatomic distance betweena metal cation and an oxygen anion and decrease in decomposition temperatureoccur in the series of bimaleates Mn, Fe, Co, Ni – 400, 355, 350, and 300ıC,accordingly [53]. It was revealed by thermogravimetry and DTA methods, thatthermal conversions of maleate and fumarates of metals (M D Mn, Co, Ni) [54]and chromium(III) acrylates [55] include processes of dehydration and oxidativedecomposition of carboxylaled ligands. Intermediate product of the anhydrousM3[Fe(OOCCH=CHCOO)3] complexes (M D Li, Na, K) [56] in the 215–300ıCtemperature range is Fe(II) maleate, with the subsequent formation of ”-Fe2O3 andmaleates/oxalates of alkali metals, and at 430–550ıC fine-dispersed particles of thecorresponding ferrites are formed.


1.01 2 3

4

50.8

0.6

0.4

0.2

0 500 1000

–2.00

1500time, min

–3.0

1.5 1.6

b

ah

lgk

1T

.103

Fig. 9.8 The kinetics of thermal decomposition of Co(II) acrylate: degree of conversion �

vs. time (a) at different temperatures: 663 K (1), 653 K (2), 643 K (3), 633 K (4), 623 K (5); andlgk vs.1/T (b)

Generally for acrylates and maleates of metals [57], kinetics of gas evolutionvs. degree of conversion �.t/ is satisfactorily approximated by the dependence(Fig. 9.8):

�.t/ D �1f Œ1 � exp.�k1�/�C .1 � �1f /Œ1 � exp.�k2�/�; (9.1)

where � D t� t0 (t0 is heating time of a sample, ˜1f D ˜.£/ at k2t ! 0, k1t !1,k1, k2 – are the effective rate constants.

Analysis of possible ways of chemical conversions of dehydrated metal car-boxylates in the assumption of energy nonequivalence of M–O bonds and for-mation of the acrylic CH2DCH–COO� and maleic �OCOCHDCHCOO� radicalsin the primary decomposition act has shown, that these radicals initiate polymer-ization of a metal-containing monomer with the subsequent decarboxylation ofmetal-containing groups. Compositions formed during thermal conversion of metalacrylates and maleates solid products can be expressed as quotas of the C–H–O-fragments; the detailed calculations are given in the works [36, 39, 46, 58]

MOz.CH2CHCOO/p�x.CHCHCOO/q�y.CH2CH/x.CHCH/H ; .for acrylates/;(9.2)

MOz.D CHCOO/2p�x.D CCOO/2q�y.D CH�/x.ıC�/H ; .for maleates/; (9.3)

where xD yD zD 0 (z ¤ 0 in case of acrylate and maleate of iron(III)), p andq are quantity of intrachain and end groups, depleted by hydrogen (pC qD 1),accordingly. The most probable way of the formation of metal oxides is the oxi-dation reactions.


MC �1CO2 D MOz C .�1 � z/CO2 C zCO (9.4)

MC �2H2O D MOz C .�2 � z/H2OC zH2: (9.5)

Escaping CO can be spent in carbonization reactions as it was observed atthermolysis of the product of radical polymerization of nickel acrylate, Ni(II)polyacrylate [59].

3Ni.s/ C 2CO.g/ D Ni3C.s/ C CO2.g/C � 122 kJ=mol Œ60� .9:6/2

4Ni.s/ C CO.g/ D Ni3C.s/ C NiO.s/C � 84 kJ=mol: (9.7)

2 It can be seen in (Fig. 9.9), that absorption of CO is accompanied by an increasein the rate of CO2 accumulation. Growth of Texp results in the reactions rate in-crease [(9.6)–(9.7)], the consequence of this effect is the observed reduction ofmaximum of CO yield, its displacement towards early stages of thermolysis up toits disappearance.

Evolutionary conversions of metal carboxylates during thermolysis were con-sidered by the example of oxoclusters of acrylate [48] and maleate of Fe(III)[47, 61]. They are convenient model objects for studying of mechanism of forma-tion of a short range ordering structure near iron atoms at thermal conversions asan initial stage of nanoparticles nucleation in metal-containing polymeric systems.

Fig. 9.9 The yield ofgaseous products duringthermolysis of Ni(II)polyacrylate at 573 K:(1) ’P;t , (2) ˛Co2; t , (3) ’CO;t ,(4) ˛CH4; t , (5) ˛H2; t . Arraysindicate the moment ofsampling of the products formass spectrometry analysis

2 �HfŒNi3C.s/� � C50:2 kJ=mol – is an estimation on the basis of �HıfŒFe3C.s/� D C25:1 kJ=mol

and comparison of the series of formation heats of Ni(II) and Fe(II).


In particular, questions about an opportunity of inclusion of a metal-containingcluster group of a monomer into a formed at thermolysis polymer and characterof their conversion during decarboxylation process are important. At which stagesof thermolysis does the destruction of a ferriferous cluster as an initial stage ofheterogeneous nucleation of nanoparticles in metal-containing polymeric systemsoccur? Is this process accompanied by the formation of metal–metal bonds, etc.?In the polynuclear oxocomplexe of Fe(III) maleate, elimination of three moleculesof crystallization water and three molecules of maleic acid, accompanying by thereorganization of ligand environments of Fe atoms, occurs already at early stages ofthermolysis.

O

OOO

O

O

OO

O

c

cc

Fe

Fe

Fe

oo

R1

R1

R1

R1

R1

R1

H

c

cc

O

O

O

O

O

OR1: CH = CHCOOH

OO

O

O

O

c

c

c

H

o

o

Fe

Fe

Fe

c

c

c

O

OO

O

O

OO

O

c

c

cc

cc

+

Results of a mass-spectrometer research of the Fe(III) maleate (FeMal) also in-dicate on the opportunity of passing of such elimination. The peak with maximalsize m=z 525 in the mass spectrum corresponds to the Fe3OŒOOCCHDCHCOO�C3ion. For studying of evolution of a short range ordering structure near Fe atomsduring isothermal decomposition of FeMal, EXAFS3-research of solid-phase inter-mediate products of thermolysis, isolated at various conversion degrees (Table 9.1,Fig. 9.10), was carried out.

According to these data, dehydration and polymerization of a desolvatedmonomer with retention of a structure fragment of a metal-carboxylated [Fe3OR6]-cluster occur during thermal conversions of FeMal to the degrees of conversioncorresponding to the FeMal-a and FeMal-b samples. However, changes of the EX-AFS spectrum occur already at the initial stage of decarboxylation of the formed

3 The method is based on the phenomenon of diffraction of photoelectrons on the surroundingof the atom, absorbing X-rays. Diffraction is revealed as a long-range fine structure of the X-rayabsorption spectrum (EXAFS) of the chosen atom. Separating an oscillating part of the EXAFSand applying Fourier transformation to it, it is possible to receive the Fourier-transformate module(FTM) which is a function of radial distribution of the surrounding of atoms near the absorbingatom accurate within phase corrections. Position (r) of the maximums of FTM, as a rule, corre-sponds to radiuses R of coordination spheres (CS) (R D r C ˛, where ˛ is the phase correction),their amplitudes ® are proportional to coordination numbers (N). Proportionality coefficient and ˛

value are determined on the basis of the analysis of the EXAFS-data of the suitable compoundswith a known structure. Besides, R, N and �2 sizes (thermal dispersion of interatomic distance,the Debye–Waller factor) can be determined on the basis of selection of values of the specifiedmagnitudes providing good conformity of the calculated and experimentally defined functions ofthe oscillating part of the EXAFS (fitting method).


Table 9.1 The structural data and FTM parameters for iron atoms in oxo maleate (III), productsof thermolysis and standard compounds [61]

Compound(Texp; �m,wt%)

The number ofcoordinationsphere, j

FTM parameters Structural data

KCrj (nm)'j (rel.units). Rj (nm) Nj

�2j � 10�4

(nm2) Q (%)

Fe(acac)3 1 0.147 3.6 0.202 6.0 0.27 2 Fe–O(0.200) (6.0)

– 0.216 0.6 – – – s.m.2 0.254 0.6 (0.295) (5.4) – Fe–C3 0.292 1.2 (0.333) (4.2) – Fe–C

FeMal (Troom) 1 0.149 3.2 0.203 5.0 0.22 1.7 Fe–O2 – – 0.194 1.0 0.33 Fe–Oa

�

3 0.293 1.2 0.329 2.0 0.23 Fe–FeFeMal-a 1 0.155 3.00 0.205 4.0 0.39 0.3 Fe–O(393 K; 6.2) 2 – – 0.186 1.0 0.15 Fe–O�

3 0.294 1.1 0.336 2.0 0.92 Fe–FeFeMal-b 1 0.155 2.8 0.205 4.0 0.37 0.5 Fe–O(438 K; 21.7) 2 – – 0.182 1.0 0.35 Fe–O�

3 0.300 1.0 0.342 2.0 0.70 Fe–FeFeMal-c 1 0.155 2.2 0.207 3.5 0.52 2 Fe–O/C(513 K; 34.5) 3 0.294 0.3 – – Fe–O/CFeMal-d 1 0.152 1.5 0.205 2.5 0.53 1.2 Fe–O/C(643 K; 46.8) – 0.217 0.3 – – – s.m.

2 0.267 0.2 0.297FeMal-e 1 0.150 1.5 0.204 3.0 0.67 1.7 Fe–O(643 K; 48.2) 2b 0.219 0.5 0.246 0.3 0.31 2.2 Fe–Fe

s.m.2 0.262 0.4 0.292 Fe–Fe

FeMal-f 1 0.148 1.6 0.203 3.0 0.70 2.5 Fe–O(643 K; 54.2) – 0.225 0.3 – – – s.m.

2 0.266 0.5 0.296 Fe–FeFeMal-g 1 0.147 1.9 0.199 4.0 0.74 0.9 Fe–O(643 K; 57.1) – 0.213 0.3 – – – s.m.

2 0.264 1.1 0.294 Fe–Fe’-Fe2O3 1 0.149 2.1 (0.196) 3.0 – Fe–O

(0.208) 3.0 – Fe–O2 0.261 2.1 (0.287) 1.0 – Fe–Fe

(0.296) 3.0 – Fe–Fe

Note: The data of X-ray diffraction studies are given in brackets. Q denotes the values of theobjective function characterizing the adjustment accuracyaThe distances between Fe and �-O (bridging oxygen)bThe peak comprises the Fe–Fe coordination sphere and the secondary maximum (s.m.) of the firstcoordination sphere


Fig. 9.10 Fourier transform module of EXAFS spectra of K-edge absorption for samples:(1) FeMal, (2) FeMal-a, (3) FeMal-b, and (4) FeMal-c

polymer. Amplitude of the FTM peak corresponding to the first CS decreases almosttwice in comparison with the value for FeMal already for the FeMal-c sample, andthe second basic maximum practically disappears that can be caused by the de-struction of a trinuclear bridge and formation of the new phases containing a set ofFe–O and Fe–C distances. Systematic increase in the amplitude of the peak fromr � 0:264 nm during thermolysis is observed, it testifies oxidation of Fe atoms withan increase in thermolysis time.

Thus, thermal conversions of unsaturated metal carboxylates allow to com-bine processes of synthesis of nanoparticles with their simultaneous stabilizationby a formed decarboxylated polymeric matrix. Sufficiently narrow character ofsize distribution of metal-containing nanoparticles and morphological peculiaritiesconnected with their spherical form are caused, most probably, by comparative ho-mogeneity of processes of thermal conversion of monomeric carboxylates. It is alsotestified by evolution of topography of a solid phase during thermolysis of metalacrylates indicating on only partial heterogeneity in the region of macrodefects [62].

Oleates and octanoates of metals are the most frequently used as molecu-lar precursors of nanostructured materials among others monomeric carboxylates.Thermolysis of these complexes in combination with surfactants and other reagentsis usually carried out in a solution of high-boiling solvents (octadecane, octadecene,docosane, octyl ether, etc.). Doubtless advantages of thermal decomposition ofcarboxylated compounds in an inert solvent are the opportunity of the controlledsynthesis of practically monodisperse nanocrystals with a high yield, narrow sizedistribution and high crystallinity [63–67].


General strategy of the obtaining of nanocrystals of semiconductor metal sulfidesby the considered method consists in thermal decomposition of metal-oleates com-plexes in an alkane-thiol [68,69]. For example, monodisperse crystal Cu2S nanopar-ticles with 18 nm (230ıC, 20 min), 15 nm (215ıC, 20 min) and 19 nm (215ıC,60 min) sizes and various forms from spherical to disk-shaped were obtained atvariation of temperature and time of a reaction and a molar ratio of oleylamine anddodecanethiol. Nanocrystals of ZnS, CdS, MnS and PbS were synthesized similarly.Stoichiometry of the initial reagents is the key factor of formation of PbS nanowiresat thermolysis (280ıC, 1 h) of the precursor obtained from Pb.NO3/2/octanoateNa/ethylenediamine/dodecanethiol reaction mixture, an optimal molar ratio is1:2:1:1.6 [70].

By special research it was shown [71, 72] that division of processes of nucle-ation and growth in a time or temperature scale is critical for the formation ofmonodisperse particles. Nonequivalence of a M–O bond and a structure of a molecu-lar precursor play an important role alongside with such factors influencing on theseprocesses as temperature and reaction time, concentration of reagents, etc. [61, 73].Detailed studying of the Fe(III) oleate structure [74] by FTIR, element analysis,X-ray photoelectron spectroscopy and DSC methods revealed that not subjected tothe special treatment after its obtaining Fe(III) oleate contains oleic acid in the com-position which is connected with the monodentate oleinic ligand (Scheme 9.3) in theform of dimer. If this oleate (as prepared) is heated at 70ıC, removal of crystalliza-tion water and destruction of the dimer occur, and the Fe(III) complex in this form isthermally stable up to 380ıC. Additional extraction in ethanol or acetone results infull removal of oleic acid (Scheme 9.3), that affects very essentially on thermal be-havior of the complex: an increase in nucleation temperature occurs and processesof nucleation and growth start to overlap, and, as a result, polydisperse particlesare formed. We shall note, that the process of a nucleus formation is connectedwith removal of oleic acid or the monodentate oleinic ligand (200–240ıC), and

C

C

O

OO

O

C

CO

O C

O

OH

extraction

OO

Fe

FeH2O

O

C

C

O

HOH5C2C2H5OH OO

OO

Fe

Fe

O

C

O

OH

Scheme 9.3 Removing oleic acid from Fe(III) oleate dimer complex


dissociation of the residual ligands (300ıC) is connected already with the forma-tion of ferric oxide nanoparticles [71].

The same laws and the formation mechanism of monodisperse nanoparticlesare characteristic for thermal conversions of Co2CFe2

3C-oleates complexes in1-octadecene at 300ıC [73,75]. Prenucleation intermediates of CoFe2O4 are formedin the 250–300ıC temperature range, but growth of nanocrystals is not observedat that; and concentration of the prenucleation centers increases sharply and theystart to grow only at temperatures exceeding thermal decomposition of Co2CFe3C

2 -oleates complexes (300–320ıC). Fine control of temperature, rates and reaction timeat this stage allows to influence efficiently both on sizes and form of nanocrystals(Fig. 9.11).

Fig. 9.11 TEM microphotographs of the CoFe2O4 nanocrystalls obtained at temperatures 305ıC(a) and 314ıC (b) and 320ıC at heating of 0 (c), 5 (d), 60 (e), 120 min (f)


It is interesting, that it is possible to obtain nanocrystals of Fe(III) oxide ofoctahedral form at similar temperature conditions, but in the presence of triocty-lammoniumbromide [76].

For the obtaining of MFe2O4 (MDCo, Ni, Mn, Fe) nanocrystals from the corre-sponding oleates complexes, the determining factor is the fact that they have closedecomposition temperatures. Otherwise, as, for example, for copper and indiumoleates, thermolysis of a mixed complex results in segregation and formation of thenanocrystalline Cu2S and In2S3 heterostructures [77].

9.2.2 Polymer Carboxylate Gels and Block Copolymersas Reactors for Nanoparticles

Introduction of ready metal nanoparticles into a polymeric matrix results frequentlyin change of properties of nanoparticles and in their aggregation and it does not al-low to achieve high concentrations of a nanophase, problems of compatibilizationappeared inevitably, etc. Sometimes methods of ex situ polymerization are used.According to this method, for example, silver nanoparticles obtained by the reduc-tion in AgNO3 solution by ascorbic acid, were added into a solution of acrylic acidand poly(ethylene glycol)methylacrylate ether at presence of a cross-linking agentand were subjected to photopolymerization (UV-irradiation, 8 min) [78].

Alternative approaches (i.e., template-mediated synthesis) are based on the ob-taining of metal nanoparticles in the medium of a polymeric (or monomeric) matrixin situ.

Amphiphilic diblock copolymers, for example, polystyrene-block-polyacrylicacid in organic and aqueous solutions are widely used for the encapsulation ofsemi-conductor nanoparticles of metal sulfides at the stage of their formation[79, 80]. One of such examples is interesting by the fact that di- and three-blockcopolymers give unique opportunities for fine regulation not only of sizes ofnanoparticles, but also regulation of morphology of metal-containing polymericnanocomposites on their basis. Quantum dots of CdS were obtained in the mi-celles of the three-block copolymer of poly(ethylene oxide)-block-polystyrene-block-poly(acrylic acid) of various architecture [81]. At mixing of dihydrate ofcadmium acetate with a diluted solution of the copolymer in THF spherical mi-celles are formed. They are so-called primary spherical inverse micelles (PSIMs)(10–50 nm), consisting of cadmium acrylate core surrounded by PS and then byPEO. Three kinds of populations of micelles with the average size equal to 40 nmare formed in an aqueous solution: mononuclear, multinuclear and aggregations ofmultinuclear micelles. Spherical micelles with a core from Cd-acrylate or CdS (af-ter treatment with H2S) are transformed into rod-like micelles at an increase inwater content. A new multistructure with Cd-acrylate cores located in a PS ma-trix, surrounded by a PEO crown, is formed if PSIMs are transferred from THFinto water before influence of H2S and this architecture is retained after convert-ing into CdS – a water-soluble supermicelle is formed. Basic parameters for such


micelle of PEO(45)-block-PS(150)-block-PAA(108)composition considering phys-ical characteristics of copolymers (density, molecular weight, chain length) werecalculated. It was founded that size of average diameter of nanocrystals and the su-permicelle equal to 4.8 nm and 50 nm, accordingly; number of quantum dots in thesupermicelle is 75, and number of CdS ion pairs in a quantum dot is 1,150.

Another structure is observed at the replacement of THF by water in case ofPSIMs with a cores from CdS. It is represented by micelles with a core from PS,and quantum dots of CdS are located in its crown. Quantum dots of CdS, in turn,are surrounded by PAA or PEO blocks.

In contrast to other polymeric templates such as dendrimers or considered aboveblock-copolymers, polymeric gels are sufficiently available because of simplicity oftheir synthesis and opportunities of easy functionalization. Indubitable advantage ofmany polymeric gels and nanocomposites on their basis is their biocompatibility.Due to this fact they can be used in medicine for creation of carriers of medicinalsubstances and for their transportation. Network structure of microgels providingprobability of nucleation and growth of nanoparticles in each void and high sensi-tivity of these systems to changes of external factors also have important value.

The general scheme of obtaining of metal nanoparticles in polymeric microgelscan be represented as follows (Scheme 9.4):

cool

cool

coolcool

cool cool

Reduction

Oxidation

Sulfidation

Me

MeMe

n+

n+n+

-

Scheme 9.4 The general scheme of metal nanoparticles synthesis in polymer gels

Various types of polymeric microgel nanocomposites containing metallic, mag-netic, semi-conductor, ceramic and other nanoparticles have been developed atthe present time [82, 83]. Properties located in microgels nanoparticles, such asstructure, sizes, size distribution, polydispersity, and also morphology of nanopar-ticles and hybrid gels, level of doping of microspheres by nanoparticles are de-fined by the reaction conditions and composition of microgels. So, hydrodynam-ical radius of particles of the microgel of poly(N -isopropyl acrylamide-acrylicacid-2-hydroxyethylacrylate) [84] in the region of 2:3 < pH < 9:2 increases from230 to 600 nm that results in an increase in the CdS content from 0.04 to 0.12 g/g.The CdS content practically linearly depends also on a mole fraction of acrylic acidin a hydrogel composition. Sizes of the synthesized in situ nanoparticles are smalland monodisperse, for example, sizes of the magnetite particles are 8:5 ˙ 1:0 nm;


level of the nanoparticles content is also easily controlled. For example, in onereaction the cycle content of the magnetite nanoparticles, obtained by precipitationin situ in pores of the copolymer of styrene and acrylic acid [85], is 3.5–8 mass%depending upon the concentration of the initial reagents; in repeated cycles it can beincreased to 20 mass%.

Microgels also give a unique opportunity for the controlled design of in-terphase/superficial structures and manipulation of superficial morphology onnano- or micrometer level. It is achieved by introduction of defined functionalgroups into composition of microgels and by character of their distribution. Thus,nanocomposite microspheres of ZnS- and CdS-poly(N -polyisopropylacrylamide-co-methacrylic acid) reveal very interesting superficial morphology in the form offigured structures that is connected with nonuniform precipitation of metal sulphidebecause of unhomogeneous distribution of metal ions within the microgel [86].

The in situ method is widely used also for the obtaining of nanocompositeson the basis of mineral clays (montmorillonite, bentonite, and other silicate clayare the most frequently used) and polymeric hydrogels. Such systems reveal im-proved mechanical characteristics due to high dispersion of mineral clays andability to exfoliation in a polymeric matrix. Polymeric hydroxyapatite nanocompos-ite was obtained by a method of precipitation in situ in the microgel of polyacrylicacid [87]. Synthesized similarly intercalates of hydrated magnesium–aluminumsilicate with poly(hydroxyethylmethacrylate)-poly(ethylene glycol methacrylate)-methacrylic acid [88] showed high strength characteristics and significant thermalstability in comparison with usual hydrogels.

An efficient variety of template assisted synthesis of metal-containing poly-meric nanocomposites is, in our opinion, homo- and copolymerization ofmonomeric metal carboxylates with the subsequent formation of nanoparticlesin situ. Nanocrystals of the PbS/polymeric gel were obtained by a combinationof homopolymerization [89] of Pb(II) dimethacrylate and its copolymerizationwith styrene and an exchange reaction with H2S [90]. ZnS nanoparticles weresynthesized similarly in a polymeric matrix [91]. Scheme of the obtaining ofPbS/polymethacrylic acid nanocomposite is shown on Fig. 9.12.

It is interesting that it is possible to obtain a monomeric precursor in the form ofnanofibres with diameter 200–300 nm and length from tens to hundreds of microns,selecting corresponding solvent during synthesis of the initial Pb(II) methacry-late. The subsequent ”-initiated polymerization allows to keep morphology of themonomer in the polymeric product and in the formed nanocomposite.

In principle, in situ method is also the perspective for obtaining hybrid nanocom-posite polymeric gels in the form of thin films. One of few examples [92] con-sists in polymerization of a monomeric carboxylate with the use of techniquesof atom transfer radical polymerization (ATRP). Controlled polymerization in thepresence of p-toluenesulfonyl chloride has allowed to carry out growth of thePb(II) polymethacrylate film on a surface of Si plate and to obtain monodis-perse PbS nanoparticles with 4 nm size and high density after exposition of thefilm by gaseous H2S. The same methodology can be put in a basis of creationof hybrid nanocomposites with a core-shell morphology. Obtaining of the SiO2


Fig. 9.12 Scheme ofsynthesis of PbS in a polymermatrix in situ

PbO

Pb

Pb Pb

n –x

n –m

H2O MA

Layer structure

Sonicate Ethanol (60°C)

H2S

= PbS nanoparticles = Polymer chains

γ-ray 60Co

Pb(MA)2

nanospheres with a shell from the block-copolymer composite containing CdSnanoparticles includes several stages (Scheme 9.5) [93]. Controlled superficially-initiated ATRP of the Pb(II) methacrylate (SiO2@PPbMAA, d D 215 nm) or MMA(SiO2@PPbMAA, d D 219 nm) is carried out on a surface of silica gel nanospheres(d D 206 nm), and then block copolymerization with the formation of silica gelwith a shell from block copolymers (SiO2 @ PPbMAA @ PMMA, d D 226 nm)or (SiO2@PMMA@PPbMAA, d D 229 nm) is carried out. CdS nanoparticles areformed in situ at treatment with H2S at 100ıC during 2 h.

These and some other methods of obtaining hybrid metal-containing polymericnanocomposites of the considered type were discussed in detail in the recentreview [94].

Finally, we shall note one more interesting method of the obtaining of metal-containing polymeric nanocomposites based on the combined synthesis both apolymeric matrix and metal nanoparticles in situ. Polyacrylic and methacrylic acidsdoped by metal-containing clusters were obtained at cocondensation of monomericacids and metals at 77 K according to the Scheme 9.6 [95].

Seemingly, linkage of the cluster particles with the polymeric matrix is carriedout with participation of the superficial atoms differing, as is well known, by highreactivity. Content of metal-containing clusters in final composites was equal to0.22–113.3mass% for PAA and 0.17–8.37% for MAA.


Scheme 9.5 Synthesis of hybrid nanocomposites with a core-shell morphology

CH2CH2C

R

COOH

+ MatomC

R

C O

OH Mn

xPolymerization

R = H, CH3

M = Pd, Cu, Ag, Au, Bi, Sn, Cd, Zn

Cocondensation (77 K)

Scheme 9.6 Preparation of polymer acids doped by metal-containing clusters

9.2.3 Sol–Gel Methods in the Obtaining of OxoclusterHybrid Materials

Significant interest in unsaturated oxocarboxylates as structural elements or peculiarstructural blocks of hybrid organo-inorganic nanocomposites (Fig. 9.13) has beenrevealed recently [96–100].

Traditional ways of obtaining such systems are frequently accompanied by phasedivision because of the difficulty of the control over size, form and distribution ofparticles of an inorganic component in an organic matrix [101]. One of the methodsof elimination of such effects is the presence of covalent bonds or strong intermolec-ular interactions, for example, hydrogen, between basic components of a system[102]. Such an approach can be realized by the participation of oxocarboxylate clus-ters functionalizated by groups able to polymerize. Due to these groups covalentlinkage of a metal-oxocluster unit with a polymeric chain is achieved. A linkageof an inorganic core with unsaturated groups of a hybrid molecule can be realized


Fig. 9.13 Molecular structure and size of a typical metal oxo cluster

SnO

alkyl group

Fig. 9.14 Fragment of the structure of hybrid nanocomposite obtained by copolymerization off(BuSn)12O14(OH)6g(OOCC.CH3/DCH2/2 and MMA

also by means of electrostatic interactions and hydrogen bonds, as it was shownfor the f(BuSn)12O14(OH)6g(OOCC(CH3/=CH2/2 oxocluster [103]. Polymethylmethacrylate–methacrylate copolymer, cross-linked by oxo-hydroxy butyltin clus-ter units, is formed at copolymerization with MMA. In this copolymer structure ofthe f.BuSn/12O14.OH/6g2C macrocation does not undergo changes during poly-merization (Fig. 9.14).

Methacrylate-substituted metal-oxocluster Hf4O2(OOCC(CH3/DCH2/12 andmethacryloylpropyltrimethoxysilane were used for the obtaining of hybrid thinfilms on the basis of silica gel with introduced hafnium oxoclusters [104, 105].Chemical binding of the components was carried out by photochemical poly-merization of methacrylate groups; alkoxy groups of the silane were exposed tohydrolysis and condensation with the formation of an oxide network (Scheme 9.7):


O

O

O

O Si

O

O

O

Si

Si

Si

Polymerization

Hydrolysis / condensation

Hf4O2(OOC(CH3)=CH2)12 + CH2=C(CH3)COO-(CH2)3-Si(OMe)3

Scheme 9.7 Synthesis of Hf(IV)/silica hybrid nanocomposite by sol-gel reactions

A similar approach was realized in a three-component system at copolymer-ization of two oxozirconium and oxohafnium clusters (M4O2(OCOC(CH3/DCH2/

with (methacryloxypropyl)trimethoxysilane [106]. Methacrylate groups of the clus-ter molecules and silane were exposed to thermal or photoinitiated polymerization,and alkoxyde groups formed an oxide SiO2 network by means of hydrolysis andcondensation. Calcination of a hybrid nanocomposite at a temperature of more than800ıC is accompanied by pyrolysis of an organic part of the nanocomposite andcondensation of the oxide network and results in the formation of the nanostruc-tured oxide material (Scheme 9.8).

Carboxylated ligands in organo-inorganic composites provide a high degree ofcross-links in such systems due to coordination bonds between a polymer and amineral component. Aggregates of inorganic particles in the hybrid poly(MMA-co-BMA-co-MAA)/TiO2 (4.6–30 wt%) composite are distributed evenly in a copoly-mer matrix and phase division in the system is not observed in contrast to theoptically opaque material, poly(MMA-co-BMA)/TiO2 [107].

9.2.4 Metal-Containing Polymeric Langmuir–Blodgett Films

Nanoparticles in the Langmuir–Blodgett (LB) films are prospective materials formolecular designs. Various sensory groups or their precursors with nonlinear op-tical groups, metal-containing complexes and nanopaticles can be introduced intosuch self-organized layers. The majority of research refers to the self-organized hy-brid nanocomposites on the basis of low-dimensional semi-conductor particles inthe Langmuir-Blodgett films. So, films containing sulphides of cadmium, zinc orlead with 100 nm thickness (34 layers) were obtained by sulfidizing of layers ofbehenates of these metals, (C21H43COO/2M [108, 109]. Films are anisotropic andtheir anisotropy increases at sulfidizing; on the basis of this fact it was concludedabout layered arrangement of the formed nanoparticles. Length of an acid molecule


silane + THF + HCl 0.5Mmix and stir for 8 hrs

(hydrolysis-condensation)

weighed amount ofZr and Hf clusters

mix and stir for 15′

stir for 15′ stir for 15′

deposition of the filmby spin-coating

UV exposure for 10′(polymerisation)

add the thermal initiator add the photoinitiator

thermal polymerizationin oil bath at 60°C

drying undervacuum at 70°C

calcination calcination

gel film

Scheme 9.8 Diagram of producing of hybrid nanocomposites

is 2.68 nm; thickness of the layer made from clusters is 1.12 nm; nanoparticlesare not spherical, diameter is 5–10 nm, thickness is 1.1–1.3 nm. There are data inliterature [110], that formation of the CdSe nanoparticles by treatment of the cad-mium arachidate films ((C19H31COO/2Cd) by H2Se vapor occurs in interlamellarspace of the films in a solid phase and is accompanied by their essential deforma-tions and even by destruction of a lamellar structure. Multilayer Langmuir–Blodgettfilms are comparatively often obtained from stearates of cadmium [111], magne-sium [112], ’-Fe2O3-stearate [113]. Formation of the self-organized structures inhydrophobic layers of stearic acid from a silver stearate film (8–14 layers) was es-tablished. The silver stearate film was moved to the electrodes (D 25 nN=m) andwas electrochemically reduced in neutral or acid solution with the formation of two-dimensional Ag clusters 20–30 nm in diameter [114].

Multilayer films of nanoparticles of cadmium, lead and copper sulphidesin oligomerous monooctadecanol ester of polymaleic acid (PMAO) were ob-tained by the combination of technique of inverse micelles and Langmuir–Blodgett [115–117].

9.3 Metal-Containing Polymeric Nanocomposite Materials of the Carboxylated Type 281

CH

COOH

O

x :y = 1.5, 7; x > y; n = 14

OC

CH

C18H37

x y n

Inverse CdS-PMAO micelles were obtained at passing of H2S through a solutionof cadmium salt of PMAO in chloroform. Monomolecular layers of CdS-PMAOnanoparticles were transferred onto a solid surface of CaF2 and Si substrates withuse of LB technique.

It is important to note, that the sizes of the nanoparticles were less than thoseobtained in stearate films and were <2 nm and, moreover, they could be controlledeffectively by variation of a molar ratio of carboxyl groups and hydrocarbon unitsof a polymeric chain [118].

Thus, methods of the obtaining of metal-containing polymeric nanocompositesare sufficiently well developed now; practically, any carboxylated systems and met-als can be used. The choice of a method is cause determined by specific aims ofobtaining of a nanostructured material with necessary properties.

9.3 Metal-Containing Polymeric Nanocomposite Materialsof the Carboxylated Type

Metal-containing polymeric nanocomposite materials have interesting magnetic,catalytic, optical and other properties in dependence on nature of a metal-containingdispersed phase. In particular, products of thermolysis of cocrystallizates of Co(II)and Fe(III) acrylates show properties of solid magnets with coercive force and resid-ual magnetization at ambient temperature equal to 0.18 T and 15.5 mT, accordingly,due to formation of ferrimagnetic Fe3O4, CoFe2O4 nanoparticles or antiferromag-netic CoO [48]. Cobalt-containing particles (average diameter is 7 nm) obtainedfrom Co(II) acrylate reveal two times more coercive force in a polymeric matrix, atthat the main metal-containing phase is CoO [42]. Spinel Zn0:5Mn0:5Fe2O4, [119]CoFe2O4, [120] and also MnFe2O4 [121] or MnFe2O4 ferrite nanocomposite, syn-thesized by pyrolysis from polyacrylate salts, and also microgel nanocompositeswith Fe3O4 [84] show superparamagnetic properties at room temperature and theyare very interesting as magnetic and X-ray adsorbing materials.

Unsaturated metal carboxylates are, undoubtedly, interesting as precursors inthe creation of multimetal superconducting ceramics, multicomponent alloys, oxideelectrodes, etc. Traditional methods of preparation of burden for high-temperaturesuperconducting (HTSC) ceramics have essential reproducibility restrictions; theyare frequently accompanied by the formation of micro- and macro-heterogeneitiesin a system, resulting in various phases, including non-conducting phases. Polymer-assisted synthesis of multicomponent ceramics allows to overcome these drawbacks


and to receive structural-homogeneous products. It is achieved, for example, bythe use of a polymeric matrix with metal ions, dispersed in it up to a molecularlevel, as in the case of polymeric complexes of Y3C, Ba2C, and Cu2C with poly-acrylic [122, 123] or polymethacrylic [124, 125] acids, which are necessary for theformation of HTSC YBa2Cu3O7�x ratios. Optimal conditions for carrying out ofpyrolysis of the considered type polymeric precursors provide use of inert argon ornitrogen atmosphere in the initial stage of the process to inhibit BaCO3 formation[126,127]. The other way is the synthesis of polymers in the presence of HTSC com-ponents – polymerization of acrylic acid in a mixture with water solutions of Y3Cnitrate, Ba2C, and Cu2C acetates [128]. More homogeneous distribution of metalions can be achieved by entering them into a monomer molecule, such an approachcan be realized by means of a reaction of copolymerization of corresponding un-saturated metal carboxylates. For this purpose, for example, Y3C, Ba2C, and Cu2Cacrylates were mixed in 1:2:3 molar proportions in minimum quantity of methanolwith its subsequent evaporation, then solid-phase copolymerization was carried-out[129, 130]. In another variant, monophase stoichiometric films of HTSC ceramicswere obtained by the spray-pyrolysis method of the solutions of yttrium, barium,and copper methacrylates. The method consists in deposition of the aerosol dropson a heated substrate, drying of a deposit, preliminary (500ıC) and final (920ıC)annealing in oxygen atmosphere [131, 132]. The obtained HTSC ceramics has87–92 K temperature of superconducting transition and density of a critical cur-rent up to 540 A/cm2. Character of dependences of electrical resistance R.T / andmagnetic susceptibility æ(T ) vs. temperature testifies sharp transition and presenceof the only superconducting phase [129] (Fig. 9.15).

The important application fields of the nanostructured polymetallic materials,obtained by carboxylated technology, can be acoustic- and optoelectronics, sen-sors, electrode materials of fuel elements, etc. Method of aerosol precipitationand pyrolysis of methacrylate solutions of carboxylates was used at the ferroelec-tric PbTi0:6Zr0:55O3 films obtaining [133]. Inter-acidation reaction by methacrylic

Fig. 9.15 Temperaturedependencies of the electricalresistance and the magneticsusceptibility of high – Tc

superconducting ceramicsfrom a copolymer of Y3C,Ba2C and Cu2C acrylates

1,2

0,8 –1,0

–0,50,4

0100 200 T,K

æ(T ),rel.unitsR (T ) / R (300)

9.3 Metal-Containing Polymeric Nanocomposite Materials of the Carboxylated Type 283

acid promoted decrease of annealing temperature (up to 650ıC); quality of a sur-face of the films without formation of pores and cracks was essentially improved.Technique of sol–gel synthesis also allows to decrease annealing temperature (upto 550ıC) at obtaining of superdispersed layered LiMO2 (MDCo, Ni, V) ox-ides (particle size is 30–50 nm and specific surface is 2:3–17 m2/g) at presenceof maleic [134] or polyacrylic [135] acids as chelating agents. The combina-tion of solid-phase polymerizations and pyrolysis of the methacrylate precursorsBaTiŒOOCC.CH3/DCH2�6 is very effective in the obtaining of the ferroelectricBaTiO3 nanopowders of the perovskite type [136]. By varying the temperaturesof thermolysis from 600 to 1; 350ıC and the nature of the reactionary medium (air,N2), it is possible to control particle sizes within wide limits (from 10 nm to 1:5 �m).

Cluster-dopped polymers is an interesting class of materials. Metal oxoclus-ters play a role of multifunction cross-linking agents and monodisperse inorganicnanofillers in such systems influencing essentially on thermal and thermome-chanical properties of a polymeric matrix. Even a small content (0.87 mol%) ofZr6O4.OH/4.CH2DC.CH3/COO/12 oxocluster in composition with its copolymerstyrene [137, 138], increases the tensile strength of polystyrene almost three times,storage modulus in high-elasticity state is 8 MPa, glass-transition temperature growswith an increase in the content of the cluster in the copolymer and reaches 110ıC at0.87 mol%. The initial decomposition temperature increases by 25ıC in comparisonwith polystyrene and is equal to 345ıC.

Hybrid nanocomposite films [104] reveal low values of permittivity ("0 D 1:8 atnuclear ratio Si/Hf D 18), such materials can be applied in various microelectronicdevices, for example, as insulating films. Three-dimensional photon crystals on thebasis of TiO2 nanostructures in a polymeric matrix were obtained by a similar wayin the system, containing methacrylic Ti(IV) alkoxyde and photopolymerized ure-thane acrylic resin, under the action of a laser beam (780 nm) with the subsequenthydrolysis and heat treatment [139].

Perspective application field of the considered hybrid nanocomposites is an al-ternative approach for the immobilization of molecular magnets. It was shown bySAXS research, that the magnetic [Mn12O12.OOCCHDCH2/16 cluster, copoly-merized with ethyl acrylate in various molar ratios (25–200 mol%) in the presenceof dibenzoyl peroxide (0.6 mass%) at 80ıC, does not undergo aggregation and is dis-tributed homogenously in a polymeric matrix [140]. The obtained hybrid polymersshowed superparamagnetic behavior at temperature shigher than 8 K; relaxationtime � , necessary for switching of the magnetic moment, follows the Arrhenius law(� D �o exp.U=kBT / �o D .4–8/ � 10�8 and energy barrier is 45–65 K). It is no-table that the obtained hybrid materials have properties of molecular magnets withcharacteristics close to the initial clusters despite rather low content of cluster units(0.1–1 mol%). So, field dependences of magnetization for methacrylate derivativeof the above-stated cluster and its copolymer with MMA/cluster D 200 composi-tion have hysteresis loop with coercive force 0.8 and 0.1 T, accordingly [141]. Thus,polymerization of magnetic clusters in the presence of organic monomers allows toobtain magnetic materials which can be processed as typical polymers, so that theykeep properties of molecular magnets.


The brief review of the perspective nanocomposite materials on the basis ofmacromolecular carboxylates testifies that it is possible to expect further intensivedevelopment of this area of macromolecular chemistry of metal carboxylates just inthis direction.

References

1. A.D. Pomogailo, V.N. Kestelman, Metallopolymer Nanocomposites (Springer, Heidelberg,2005)

2. M.Y. Gao, Y. Yang, B. Yang, F.L. Bian, J.C. Shen, J. Chem. Soc. Chem. Commun. 2779(1994)

3. Y. Wang, A. Suna, W. Mahler, R. Kasowski, J. Chem. Phys. 87, 7315 (1987)4. A.V. Volkov, M.A. Moskvina, I.V. Karachentsev, A.V. Rebrov, A.L. Volynskii, N.F. Bakeev,

Vysokomol. Soedin. A 40, 45 (1998)5. L. Sheeney-Haj-Ichia, Z. Cheglakov, I. Willner, J. Phys. Chem. B 108, 11 (2004)6. G. Liu, X. Yan, Z. Lu, S.A. Curda, J. Lal, Chem. Mater. 17, 4985 (2005)7. Y. Yang, J. Huang, B. Yang, S. Liu, J. Shen, Synth. Met. 91, 1773 (1997)8. J. Wang, L. Gao, J. Mater. Sci. Lett. 18, 181 (1999)9. H. Yokoi, Y. Mori, Y. Fuijse, Bull. Chem. Soc. Jpn. 68, 2061 (1995)

10. H. Yokoi, Y. Mori, T. Mitani, S. Kawata, Bull. Chem. Soc. Jpn. 65, 1989 (1992)11. R.F. Ziolo, E.P. Gianneliss, B.A. Weinstein, M.P. O’Horo, B.N. Ganguly, V. Mehrotra,

M.W. Russel, D.R. Huffman, Science 257, 219 (1992)12. G.-J. Lee, S. Shin, S.-G. Oh, Chem. Lett. 33, 118 (2004)13. Y. Gotoh, R. Igarashi, Y. Ohkoshi, M. Nagura, K. Akamatsu, S. Deki, J. Chem. Mater. 10,

2548 (2000)14. J.G. Worden, A.W. Shaffer, Q. Huo, Chem. Commun. 518 (2004)15. J.G. Worden, A.W. Shaffer, Q. Huo, Langmuir 20, 8343 (2004)16. K.-M. Sung, D.W. Mosley, B.R. Peelle, J.M. Jacobson, J. Am. Chem. Soc. 126, 5064 (2004)17. F. Patolsky, Y. Weizmann, O. Lioubashevshi, I. Willner, Angew. Chem. Int. Ed. 41, 2323

(2002)18. Q. Dai, J.G. Worden, J. Trullinger, Q. Huo, J. Am. Chem. Soc. 127, 8008 (2005)19. E.B. Barmatov, A.S. Medvedev, D.A. Pebalk, M.V. Barmatov, N.A. Nikonorova, S.B. Zezin,

V.P. Shibaev, Vysokomol. Soedin. A 48, 1045 (2006)20. H. Althues, R. Palkovits, A. Rumplecker, P. Simon, W. Sigle, M. Bredol, U. Kynast, S. Kaskel,

Chem. Mater. 18, 1068 (2006)21. Q.-L. Zhang, L.-C. Du, Y.-X. Weng, L. Wang, H.-Y. Chen, J.-Q. Li, J. Phys. Chem. B 108,

15077 (2004)22. Y.-X. Weng, L. Li, Y. Liu, L. Wang, G.-Z. Yang, J. Phys. Chem. B 107, 4356 (2003)23. S. Ko, M. Park, J.S. Lee, Y.S. Kim, D.Y. Ryu, U. Jeong, Chem. Commun. 1855 (2009)24. M. Mostafavi, N. Keglouche, M.-O. Delcourt, J. Belloni, Chem. Phys. Lett. 167, 163 (1990)25. A. Henglein, T. Linnert, P. Mulvaney, Ber. Bunsen. Ges. Phys. Chem. 94, 1449 (1990)26. K. Huber, T. Witte, J. Hollmann, S. Keyker-Baumann, J. Am. Chem. Soc. 129, 1089 (2007)27. H. Mori, A.H.E. Muller, J. E. Klee, J. Am. Chem. Soc. 125, 3712 (2003)28. L. Song, M. Zhu, Y. Chen, K. Haraguchi, Macromol. Chem. Phys. 209, 1564 (2008)29. P.T. Snee, R.C. Somers, G.P. Nair, J.P. Zimmer, M.G. Bbawendi, D.G. Nocera, J. Am. Chem.

Soc. 128, 13320 (2006)30. X. Wu, H. Liu, J. Liu, K.N. Haley, J.A. Treadway, J.P. Larso, N. Ge, F. Peale, M.P. Bruchez,

Nat. Biotechnol. 21, 41 (2003)31. M.A. Petruska, A.P. Bartko, V.I. Klimov, J. Am. Chem. Soc. 126, 714 (2004)32. B. Kairdolf, A.M. Smith, S. Nie, J. Am. Chem. Soc. 130, 12866 (2008)33. Y. Kang, T.A. Taton, J. Am. Chem. Soc. 125, 5650 (2003)

References 285

34. L.I. Halaoui, Langmuir 17, 7130 (2001)35. E.A. Karpushkin, S.B. Zezin, Vysokomol. Soedin. B 51, 322 (2009)36. E.I. Aleksandrova, G.I. Dzhardimalieva, A.S. Rozenberg, A.D. Pomogailo, Izv. Akad. Nauk.

SSSR Ser. Khim. 303 (1993)37. A.S. Rozenberg, G.I. Dzhardimalieva, A.D. Pomogailo, Polym. Adv. Technol. 9, 527 (1998)38. A.D. Pomogailo, A.S. Rozenberg, G.I. Dzhardimalieva, Controlled Pyrolysis of Metal-

Containing Precursors as a Way for Syntheses of Metallopolymer Nanocomposites. Chapterin Book: “Metal-Polymer Nanocomposites”, ed. by. L. Nicolais, G. Carotenuto (Wiley, 2005,pp.75–122)

39. A.S. Rozenberg, A.A. Rozenberg, G.I. Dzhardimalieva, A.D. Pomogailo, Kolloid. Zh. 67, 70(2005)

40. E. Sowka, M. Leonowicz, J. Kazmierczak, A. Slawska-Waniewska, A.D. Pomogailo,G.I. Dzhardimalieva, Phys. B Condens. Matter. 384, 282 (2006)

41. E.I. Aleksandrova, G.I. Dzhardimalieva, A.S. Rozenberg, A.D. Pomogailo, Izv. Akad. Nauk.SSSR Ser. Khim. 308 (1993)

42. M. Lawecka, A. slawska-Waniewska, K. Racka, M. Leonowicz, G.I. Dzhardimalieva, A.S.Rozenberg, A.D. Pomogailo, J. Alloys Compd. 369, 244 (2004)

43. A.S. Rozenberg, E.I. Aleksandrova, G.I. Dzhardimalieva, A.N. Titkov, A.D. Pomogailo, Izv.Akad. Nauk. SSSR Ser. Khim. 1743 (1993)

44. A.S. Rozenberg, G.I. Dzhardimalieva, N.V. Chukanov, A.D. Pomogailo, Kolloid. Zh. 67, 57(2005)

45. A.S. Rozenberg, E.I. Aleksandrova, G.I. Dzhardimalieva, N.V. Kyr’yakov, P.E. Chizhov,V.I. Petinov, A.D. Pomogailo, Izv. Akad. Nauk. SSSR Ser. Khim. 885 (1995)

46. A.S. Rozenberg, E.I. Aleksandrova, N.P. Ivleva, G.I. Dzhardimalieva, A.V. Raevskii,O.I. Kolesova, I.E. Uflyand, A.D. Pomogailo, Izv. Akad. Nauk. SSSR Ser. Khim. 265 (1998)

47. A.T. Shuvaev, A.S. Rozenberg, G.I. Dzhardimalieva, N.P. Ivleva, V.G. Vlasenko,T.I. Nedoseikina, T.A. Lubeznova, I.E. Uflyand, A.D. Pomogailo, Izv. Akad. Nauk. SSSRSer. Khim. 1505 (1998)

48. M. Lawecka, M. Kopcewicz, A. Slawska-Waniewska, M. Leonowicz, J. Kozubowski,G.I. Dzhardimalieva, A.S. Rozenberg, A.D. Pomogailo, J. Nanopart. Res. 5, 373 (2003)

49. A.S. Rozenberg, G.I. Dzhardimalieva, A.D. Pomogailo, Dokl. Akad. Nauk. 356, 66 (1997)50. A.S. Rozenberg, G.I. Dzhardimalieva, A.D. Pomogailo, Russ. Chem. Rev. (2009)51. M.A. Porai-Koshits, in Krystallokhimiya (Itogi nauki i tekhniki), Crystal Chemistry

(Advances in Science and Crystal Engineering), vol. 15, ed. by E.A. Gilinskaya (VINITI,Moscow, 1981), p. 3

52. Yu.M. Shulga, O.S. Roshchupkina, G.I. Dzhardimalieva, I.V. Chernushevich, A.F. Dodonov,Y.V. Baldokhin, P.Ya. Kolotyrkin, A.S. Rozenberg, A.D. Pomogailo, Izv. Akad. Nauk. SSSRSer. Khim. 1739 (1993)

53. L.I. Yudanova, V.A. Logvinenko, L.A. Sheludyakova, N.F. Yudanov, N.I. Alferova,V.I. Alekseev, P.P. Semyannikov, V.I. Lisovain, Zh. Neorg. Khim. 53, 1559 (2008)

54. B.S. Randhawa, M. Kaur, J. Therm. Anal. Calorim. 89, 251 (2007)55. M. Badea, R. Olar, G. Vasile, A. Emandi, V. Pop, D. Marineski, J. Therm. Anal. Calorim. 81,

273 (2005)56. B.S. Randhawa, K. Sweety, J. Therm. Anal. Calorim. 62, 295 (2000)57. A.D. Pomogailo, G.I. Dzhardimalieva, A.S. Rozenberg, D.N. Muraviev, J Nanopart. Res. 5

497 (2003)58. A.S. Rozenberg, Formation of High Dispersion Particles in Heterogeneous Reactions. Thesis

. . . doct. Khim. Nauk. (ICP in Chernogolovka RAS, Chernogolovka, 1997)59. A. Rosenberg, GI Dzhardimalieva, NV Chukanov, AD Pomogaylo, Kolloid. Zh. 67(1), 57

(2005)60. V.P. Glushko (ed.), Thermal Constants of Compounds (Izd. AN SSSR, Moscow, 1972)61. A.D. Pomogailo, V.G. Vlasenko, A.T. Shuvaev, A.S. Rozenberg, G.I. Dzhardimalieva,

Kolloid. Zh. 64, 524 (2002)62. A.D. Pomogailo, G.I. Dzhardimalieva, A.S. Rozenberg, Acta Phys. Polonica. A 102, 135

(2002)


63. S. Sun, C.B. Murray, D. Weller, L. Folks, A. Moser, Science 287, 1989 (2000)64. S.-H. Choi, E.-G. Kim, T. Hyeon, J. Am. Chem. Soc. 128, 2520 (2006)65. K. An, N. Lee, J. Park, S.C. Kim, Y. Hwang, J.G. Park, J.Y. Kim, J.H. Park, M.J. Han, J. Yu,

T. Hyeon, J. Am. Chem. Soc. 128, 9753 (2006)66. T. Hyeon, Chem. Commun. 927 (2003)67. C.S. Li, Y.N. Li, Y. Wu, B.S. Ong, R.O. Loutfy, Sci. China E. Technol. Sci. 51, 2075 (2008)68. S.-H. Choi, K. An, E.-G. Kim, J.H. Yu, J.H. Kim, T. Hyeon, Adv. Funct. Mater. 19, 1645

(2009)69. S.-H. Choi, E.-G. Kim, J. Park, K. An, N. Lee, C. Kim, T. Hyeon, J. Phys. Chem. B 109,

14792 (2005)70. J. Chen, L. Chen, L.-M. Wu, Inorg. Chem. 46, 8038 (2007)71. J. Park, K. An, Y. Hwang, J.-G. Park, H.-J. Noh, J.-Y. Kim, J.-H. Park, N.-M. Hwang,

T. Hyeon, Nat. Mater. 3, 891 (2004)72. D.V. Talapin, E.V. Shevchenko, H. Weller, Synthesis and characterization of magnetic

nanoparticles. in Nanoparticles ed. by G. Schmid (Wiley-VCH, Weiheim, 2004), p. 19973. N. Bao, L. Shen, W. An, P. Padhan, C.H. Turner, A. Gupta, Chem. Mater. 21, 3458 (2009)74. L.M. Bronstein, X. Huang, J. Retrum, A. Schmucker, M. Pink, B.D. Stein, B. Dragnea, Chem.

Mater. 19, 3624 (2007)75. N. Bao, L. Shen, Y. Wang, P. Padhan, A. Gupta, J. Am. Chem. Soc. 129, 12374 (2007)76. A. Shavel, B. Rodriguez-Gonzalez, J. Pacifico, M. Spasova, M. Farle, L.M. Liz-Marzan,

Chem. Mater. 21, 1326 (2009)77. S.H. Chio, E.G. Kim, T. Hyeon, J. Am. Chem. Soc. 128, 2520 (2006)78. W.-F. Lee, K.-T. Tsao, J. Appl. Polym. Sci. 100, 3653 (2006)79. M. Moffit, H. Vali, A. Eisenberg, Chem. Mater. 10, 1021 (1998)80. M. Moffit, L. McMahon, V. Pessel, A. Eisenberg, Chem. Mater. 7, 1185 (1995)81. N. Duxin, F. Liu, H. Vali, A. Eisenberg, J. Am. Chem. Soc. 127, 10063 (2005)82. S.A. Meenach, K.W. Anderson, J.Z. Hilt, Hydrogel Nanocomposites: Biomedical Applica-

tions, Biocompatibility, and Toxicity Analysis Chapter in: Safety of Nanoparticles, Nanos-tructure Science and Technology, ed. by T.J. Webster (Springer, Heidelberg, 2009)

83. S. Laurent, D. Forge, M. Port, A. Roch, C. Robic, L.V. Elst, R.N. Muller, Chem. Rev. 108,2064 (2008)

84. J. Zhang, S. Xu, E. Kumacheva, J. Am. Chem. Soc. 126, 7908 (2004)85. M. Breulmann, H. Colfen, H.-P. Hentze, M. Antonietti, D. Walsh, S. Mann, Adv. Mater. 10,

237 (1998)86. C. Bai, Y. Fang, Y. Zhang, B. Chen, Langmuir 20, 263 (2004)87. X. Shen, H. Tong, Z. Zhu, P. Wan, J. Hu, Mater. Lett. 61, 629 (2007)88. Y. Xiang, Z. Peng, D. Chen, Eur. Polym J. 42, 2125 (2006)89. T. Cui, F. Cui, J. Zhang, J. Wang, J. Huang, C. Lu, Z. Chen, B. Yang, J. Am. Chem. Soc. 128,

6298 (2006)90. M. Gao, Y. Yang, B. Yang, F. Bian, J. Shen, J. Chem. Soc. Chem. Commun. 2779 (1994)91. Y. Yang, J. Huang, S. Liu, J. Shen, J. Mater. Chem. 7, 131 (1997)92. J.-Y. Wang, W. Chen, A.-H. Liu, G. Lu, G. Zhang, J.-H. Zhang, B. Yang, J. Am. Chem. Soc.

124, 13358 (2002)93. T. Cui, J. Zhang, J. Wang, F. Cui, W. Chen, F. Xu, Z. Wang, K. Zhang, B. Yang, Adv. Funct.

Mater. 15, 481 (2005)94. H.-Z. Sun, B. Yang, Sci. China E. Technol. Sci. 51, 1886 (2008)95. G. Cardenas, C. Munoz, H. Carbaco, Eur. Polym. J. 36, 1091 (2000)96. H. Peterlik, P. Fratzl, Monatsh. Chem. 137, 529 (2006)97. C. Sanchez, B. Julian, P. Belleville, M. Popall, J. Mater. Chem. 15, 3559 (2005)98. U. Schubert, Chem. Mater. 13, 3487 (2001)99. G. Kickelbick, Prog. Polym. Sci. 28, 83 (2003)

100. U. Schubert, J. Sol–Gel Sci. Technol. 26, 47 (2003)101. A.D. Pomogailo, Usp. Khim. 69, 60 (2000)102. S. Trabelsi, A. Janke, R. Hassler, N.E. Zafeiropulous, G. Fornasieri, S. Bocchini, L. Rozes,

M. Stamm, J.F. Gerard, C. Sanchez, Macromolecules 38, 6068 (2005)

References 287

103. F. Ribot, F. Banse, C. Sanchez, M. Lahcini, B. Jousseaume, J. Sol–Gel Sci. Technol.8, 529(1997)

104. S. Gross, A. Zattin, V.D. Noto, S. Lavina, Monatsh. Chem. 137, 583 (2006)105. L. Armelao, C. Eisenmenger-Sittner, M. Groenewolt, S. Gross, C. Sada, U. Schubert,

E. Tondello, A. Zattin, J. Mater. Chem. 15, 1838 (2005)106. L. Armelao, H. Bertagnolli, D. Bleiner, M. Groenewolt, S. Cross, V. Krishnan, C. Sada,

U. Scubert, E. Tondello, A. Zattin, Adv. Funct. Mater. 17, 1671 (2007)107. F.X. Perrin, V.N. Nguen, J.L. Vernet, J. Appl. Polym. Sci. 97, 92 (2005)108. F.N. Dultsev, L.L. Svechnikova, Thin Solid Films 288, 103 (1996)109. F.N. Dultsev, L.L. Svechnikova, Zh. Strukt. Khim. 38, 803 (1997)110. R.S. Urquhart, D.N. Furlong, T. Gegenbach, N.D. Geddes, F. Grieser, Langmuir 11, 1127

(1995)111. Y.H. Park, B.I. Kim, Y.J. Kim, J. Appl. Polym. Sci. 63, 619, 779 (1997)112. Z. Gu, X. Yang, Z. Lu, Y. Wei, J. Southeast. Univ. 24, 103 (1994)113. X. Peng, Y. Zhang, J. Yang, B. Zou, L. Xiao, T. Li, J. Phys. Chem. 96, 3412 (1992)114. Y. Zhang, Z. Xie, B. Hua, B. Mao, Y. Chen, Q. Li, Z. Tian, Sci. China B 40, 397 (1997)115. L.S. Li, J. Jin, Y.Q. Tian, Y.Y. Zhao, S.M. Jiang, Z.L. Du, G.H. Ma, N. Zheng, Supramol. Sci.

5, 475 (1998)116. L.S. Li, L. Qu, R. Lu, X. Peng, Y.Y. Zhao, T.J. Li, Thin Solid Films 327–329, 408 (1998)117. L.J. Wang, L.S. Li, Q. Li, X. Peng, Y.Y. Zhao, T.J. Li, Mol. Cryst. Liq. Cryst. Sci. Technol.

A Mol. Cryst. Liq. Cryst. 294, 473 (1997)118. J. Jin, L.S. Li, Y.Q. Tian, Y.J. Zhang, Y. Liu, Y.Y. Zhao, T.S. Shi, T.J. Li, Thin Solid Films

327–329, 559 (1998)119. X.M. Liu, S.-Y. Fu, J. Magn. Magn. Mater. 308, 61 (2007)120. X.M. Liu, S.Y. Fu, H.M. Xiao, C.J. Huang, Physica B 370, 14 (2005)121. H.-M. Xiao, X.-M. Liu, S.-Y. Fu, Compos. Sci. Technol. 66, 2003 (2006)122. S. Dubinsky, Y. Lumelsky, G.S. Grader, G.E. Shter, J. Polym. Sci. B Polym. Phys. 43, 1168

(2005)123. S. Dubinsky, Y. Lumelsky, G.S. Grader, G.E. Shter, M.S. Silverstein, J. Polym. Sci. B Polym.

Phys. 43, 1168 (2005)124. J.C.W. Chien, B.M. Gong, J.M. Madsen, R.B. Hallock, Phys. Rev. B. 38, 11853 (1988)125. J.C.W. Chien, B.M. Gong, X. Mu, Y. Yang, J. Polym. Sci. Polym. Chem. Ed. 28, 1999 (1990)126. M.S. Silverstein, Y. Najary, Y. Lumelski, I. Von Lampe, G.S. Grader, G.S. Shter, Polymer 45,

937 (2004)127. S. Dubinsky, G.S. Grader, G.E. Shter, M.S. Silverstein, Polym. Degrad. Stab. 86, 171 (2004)128. I. Valente, C. Sanchez, M. Henri, J. Livage, Industrie Ceramique 836, 193 (1989)129. A.D. Pomogailo, V.S. Savostyanov, G.I. Dzhardimalieva, A.V. Dubovitskii, A.N. Ponomarev,

Izv. Akad. Nauk. SSSR Ser. Khim. 1096 (1995)130. V.S. Savostyanov, V.A. Zhorin, G.I. Dzhardimalieva, A.D. Pomogailo, A.V. Dubovitskii,

V.N. Topnikov, M.K. Makova, A.N. Ponomarev, Dokl. Akad. Nauk. 318, 378 (1991)131. Yu. A. Tomashpolskii, L.F. Rybakova, O.F. Fedoseeva, I.A. Noskova, S.A. Menshykh, Neorg.

Mater. 37, 75 (2001)132. T.A. Starostina, O.P. Syutkina, L.F. Rybakova, V.V. Bogatko, R.R. Shifrina, Yu. N. Venevtsev.

Zh. Neorg, khim. 37, 2402 (1992)133. Yu. A. Tomashpolskii, L.F. Rybakova, T.V. Lunina, O.F. Fedoseeva, S.G. Prutchenko,

S.A. Menshykh: Neorg. Mater. 37, 596 (2001)134. I.-H. Oh, S.-A. Hong, Y.-K. Sun, J. Mater. Sci. 32, 3177 (1997)135. Y.-K. Sun, I.-H. Oh, S.-A. Hong, J. Mater. Sci. 31, 3617 (1996)136. H.-J. Glasel, E. Hartmann, D. Hirsch, R. Bottcher, C. Klimm, D. Michel, H.-C. Semmelhack,

J. Hormes, H. Rumpf, J. Mater. Sci. 34, 2319 (1999)137. S. Puchegger, H. Rennhofer, F.R. Kogler, D. Loidl, S. Bernstoff, U. Schubert, H. Peterlik,

Macromol. Rapid Commun. 28, 2145 (2007)138. F.R. Kogler, T. Koch, H. Peterlik, S. Seidler, U. Schubert, J. Polym. Sci. B Polym. Phys. 45,

2215 (2007)


139. X.-M. Duan, H.-B. Sun, K. Kaneko, S. Kawata, Thin Solid Film 453–454, 518 (2004)140. F. Palacio, P. Oliete, U. Schubert, I. Mijatovic, N. Husing, H. Peterlik, J. Mater. Chem. 14,

1873 (2004)141. S. Willemin, B. Donnadien, L. Lecren, B. Henner, R. Clerac, C. Guerin, A.V. Pokrovskii,

J. Larionova, New J. Chem. 28, 919 (2004)

Chapter 10Conclusion

As appears from the analysis of the subject considered in the book, monomer andpolymer metal carboxylates belong to an entirely new interdisciplinary science atthe junction where the organic, physical, coordination, and high molecular branchesof chemistry intersect. It has become possible to speak about all the features typicalof an independent branch of chemistry: an intrinsic scientific matter, methodologyand abundant experimental materials. The progress in this field is very promising.Firstly, a large variety of synthetic approaches have been developed and optimizedallowing the obtaining of certain unsaturated metal carboxylates practically with aquantitative yield. In high molecular compound chemistry problems of synthesisand purity of monomers are very important. From this point of view, one can assertthe development of a new class of organometallic monomers. For their synthesis theapproaches which prevent polymerization at this stage should be used (namely, inertatmosphere, nonaqueous or dysphasic medium, hydrothermal synthesis, specific ad-ditives, low temperatures, and so on).

In turn, the experimental study of molecular structures of unsaturated carboxylicacids salts is not a simple task because a variety of compositions and structuresof conventional (“saturated”) carboxylates is extended with structural function ofthe multiple bonds itself. Most often, vibration and electronic spectroscopy to-gether with magnetochemistry and ”-resonance spectroscopy allow one to obtaincomplete quantitative information about the structure, coordination number andpolyhedron, dentatity and coordination mode of the carboxylic ligand. Bidentate-bridging, bidentate-cycle or chelate coordination are the most widely spread types.These modes appear often in combination in one molecule. However, the crystal-lochemical studies of unsaturated metal carboxylates are not as numerous as incomparison with their saturated analogs. The same situation is observed with respectto polynuclear metal complexes containing unsaturated carboxyl ligands. Significantprogress is expected in this direction.

Polymerization of unsaturated metal carboxylates is a unique way for synthesisof metallopolymers, each monomer unit of which contains an equivalent of metal.However, these polymer products are obtained only by free radical polymerization.In some cases, a deviation from the main equation of free-radical polymeriza-tion is observed because of a purely individual influence of the transition metal.The kinetics of such processes is studied widely enough. The effective initiating


289

290 10 Conclusion

systems are developed specially for such monomers including ATRP approaches.Special mention in this book has been made to problems of polymerization of thesemonomers, especially to competitive reactions, processes of stereo regulation aswell as alternation in copolymerization. Copolymerization of the monomers underdiscussion with conventional monomers enlarges the possibilities of inserting metalions into the macrochain. For some salts, such as tin carboxylate monomers and oth-ers, copolymerization studies with styrene, acrylonitrile, MMA, etc. are progressedto the stage of determining relative reactivity constants. A deep comprehensionof processes accompanying these reactions can enrich the general theory of free-radical polymerization. The data on polymerization of acetylene type carboxylatesare rather limited, knowledge about diene metal carboxylates is almost lacking.

Metallopolymers possess practically unlimited possibilities in the molecular andsupramolecular structural organization. Many properties of metal-containing poly-mers are related to the formation of ion aggregates and multipletes in ionomersas well as three-dimensional network polymers with unusual topology structures,and interpenetrating polymer alloys. Of great interest are hybrid supramolecularstructures on the base of metal dicarboxylates and so on. It is reasonable to expectconsiderable advances in synthetic strategies of intercalation chemistry with respectto acrylate ions followed by polymerization in interlayer spaces of highly organizedinorganic medium, liquid crystals, micelles, and bilayer lipids and so on.

A very interesting aspect of these works is a comparative analysis of polymermetal carboxylates synthesized by complementary methods – polymerization andcopolymerization of respective monomers and by polymer-analogous reactions us-ing previously prepared polyacids. For a long time the latter approach has beensuccessfully elaborated utilizing synthetic, artificial, and nature polyacids. Namely,these objects (as a rule, previously ionized polymer acids) were the basis for draw-ing the theoretical conclusions on the binding of metal ions with macromolecularligands as well as for determining cooperative character of the interactions in suchsystems. The ability of carboxylate ion to bind the metal cation essentially dependson its polymer surroundings: if the carboxyl group is homogeneously distributed ina polymer chain including stereoregular structures or if the polymer gives rise toa cross-linked chain, and if copolymer macromolecule reveal statistic, alternate orblock (grafted) structure.

As a matter of fact, binding of heterogeneous metal ions with polyacids is a morecomplicated problem for both the mutual copolymerization of metal carboxylatesthemselves and polymer-analogous transformations. At the same time, such an ap-proach is the most promising area in the solution to the problem under discussion inboth application and theoretical aspects. In the future, considerable results in thesefields should be expected.

A practical perspective of almost every direction of science is a driving forcefor their progress. Monomer and polymer metal carboxylates are distinguished bya great variety of properties that predetermine their applications as efficient cata-lysts of different reactions of the main organic synthesis, as new materials such asmagnetic, electric, optical, sensor and other ones. They are proved to be used as po-tential reagents for enhancing the properties of traditional polymers. For a long time

10 Conclusion 291

the metal carboxylates and polymers had a wide application as sorbents, flocculatingagents, and water-absorbing materials. Nevertheless, we are still at an early stage instudying all the possibilities of these promising materials. In recent years, the pos-sible ways have been found to transform isolated metal ions in polymer acids intometal nanoparticles. At the same time, a polycarboxylate matrix serves as stabilizingagent preventing aggregation of nanoparticles formed. Now this field has progressedvery intensively.

In theoretical aspect the appearance of novel initiating systems (includingnon-radical types) and establishing the new mechanism of polymerization trans-formations (radical-coordination, ionic-coordination reactions) should be expected.At many stages of analysis in the book we noted the tendency of carboxylatesto form the coordination polymers such as two- and three-dimensional ones.Systematic studies in this way will promote the solution of the important prob-lems – development of materials with unusual properties as well as theoretical basisof synthesis and polymerization of new classes of monomers.

Finally, special mention should be made that the subject of this monograph isrestricted only by polymerization transformations of unsaturated metal carboxy-lates. The authors do not provide the analysis of other important reactions such ashydrogenation, isomerization, hydrosylilation, epoxidation of these monomers thatwill be considered in future.

Index

Absorption, 232, 233Acetylacetone, 30Acetylene, 8, 98Acid

acetylenedicarboxylic, 35, 70, 96allylacetic, 86allylmalonic, 86citraconic, 85cluster-containing, 95, 96crotonic, 85’, “-dimetacrylic, 85mesaconic, 85phenylacetic, 107propiolic, 85, 96tiglinic, 85vinylacetic, 86vinylbenzoic, 107

(Meth)acrylatesalkali metals, 27d -elements, 27lanthanoids, 27oxopolynuclear, 29synthesis, 27

Activation energy, 107, 109, 111, 113, 117,122, 138

Agentchain transfer, 106compatibilization, 222complexing, 145cross-linking, 194, 222, 235, 240, 242

divinylbenzene, 195oxidizing, 249

Aggregatescluster, 185ionic, 183, 184micelle-like, 203, 204

Aggregationsionic, 182, 185, 189ions, 179

Alcohol vinyl, 17Alkenoate, 120Alkoxide

europium triisopropoxide, 32Ti(IV) methacrylate, 192, 193tin(IV) isopropoxide, 35titanium(IV), 32, 35, 107, 193

Allyl alcohol, 86Allyltitanocene, 37Ammonium persulfate, 109Analysis, 28

regression, 239Anhydride maleic, 9Associate, 152Atom transfer radical polymerization (ATRP),

108, 275, 290Azeotrope distillation, 27Azobis(isobutyronitrile) (AIBN), 15, 106, 113

Benzimidazole, 66, 67, 81Benzotriazol, 33Benzoyl peroxide, 106Benzoylacetone, 30Bethain, 91Bifunctional monomers, 119Bioelements, 172Biopolymer, 145

swelling, 145Bipyridine, 66, 79, 80, 93, 108Bis(cyclopentadienyl)titanium dichloride, 31Bisphenol A, 225Block-copolymer, 19, 165, 180, 190, 204, 220,

221, 225, 273, 274, 276Blue silver, 258Bond

acetylene, 96allyl, 37coordination, 117, 145, 171

293

294 Index

covalent, 100ethylene, 8ethylenic, 8hydrogen, 2, 18, 68, 74, 81, 83, 97, 260hydrogen intramolecular, 16, 69hydrogen, asymmetrical, 69hydrogen, intra- and intermolecular, 74hydrogen, symmetry, 69intermolecular, 75intramolecular, 148M–O, 62metal-ligand, 61, 63metal-metal, 63, 67, 95multiple, 3, 74, 128, 210unsaturated, 195

-Bond, 57, 85–88, 127Bond energy, 116

Calculationquantum-chemically, 2thermochemical, 2

Carbon oxide, 8Carboxyl acid

acrylic, 2diacetylene

photopolymerization, 3Carboxylate shift, 3Carboxylic

“-dicarboxylic, 9Carboxylic acid

“, ”-unsaturated, 127trans, trans-2,4-hexadieneoic acid, 126acetylene, 3acetylenecarboxylic, 10, 13acetylenedicarboxylic, 10, 14aconitic, 9acrylic, 3, 8, 11, 21all-trans-retinoic, 259allylacetic, 11angelic, 8arachidonic, 92-bromoacrylic, 112-bromomethyl-acrylic, 11carboran-containing, 1chloroacetic, 18cis, cis-Muconic, 14cis-oleinic, 12citraconic, 9crotonic, 3, 8.C/-cytronellic, 8dehyrogeranic, 9diacetylene, 3dicarboxylic unsaturated, 9

’, “-dicarboxylic unsaturated, 9’- and “-eleostearic, 8donor-acceptor properties, 2erucic, 82-ethylacrylic, 11fumaric, 3, 9, 14geranic acid, 82-hexynoic, 13glutaric, 155iminodiacetic, 18isocrotonic, 8itaconic, 9, 14, 17’-linoleic, 12linoleic acid, 8”-linolenic, 13maleic, 3, 9, 14maleic acid, 9maleic acid monoamide, 14mesaconic, 9methacrylic, 3, 11, 15, 21methacrylic acid, 8methylfumaric, 9methylmaleic, 9methylpropiolic, 103-methyl-propiolic, 13nervonic, 126-octadecynoic, 102-octenoic, 112-octynoic, 10, 13oleic, 3palmitoleinic, 12palmitooleic acid, 810,12-penta-cosadiynoic, 102-pentenic, 114-pentynoic, 13phenylpropiolic, 10phenylpropynoic, 13propiolic, 102-propylacrylic, 11ricinoleic, 12sorbic, 8stearolic acid, 10trans-oleinic, 1210-undecenoic, 12tricarballylic, 155undecylenic acid, 8unsaturated, 7, 19, 126, 289

monobasic, 7tribasic, 9

vinylbenzoic, 3, 11, 17vinylbenzoic acid, 8

Carboxylic acidsacetic, 29cinnamic, 33

Index 295

fumaric, 28fumaric acid, 29itaconic, 28maleic, 28methacrylic, 31, 35unsaturated, 30, 39unsaturated monobasic, 28vinylbenzoic, 35vinylphenylacetic, 35

Carboxylic ionfunction, 2geometry, 2intermediate symmetry, 2

Catalysis interfacial, 170Catalyst

bimetallic, 252copper(I) bromide, 108heterogeneous, 245, 246immobilized, 245metallopolymer, 249oxidation, 88, 247phase transfer, 70self-supported, 246

Cellulose, 22carboxymethyl, 22, 171

Chainacetylene-acetylene contacts, 126alternation, 131charged, 149conformation, 17cross-linked, 195, 290functional groups, 148length, 16Li–O tetrahedrons, 127microstructure, 134, 182polymer, 134, 147, 149, 152reactive centers, 147two-dimensional infinite, 199

Chalcogenide, 257Chromatography

gel permeation, 105Clays, 234

bentonite, 275montmorillonite, 275

Cluster, 94carbonyl, 38, 95carboxylate, 94heterometallic, 94heteronuclear, 38ionic, 190molybdenum, 38organometallic, 95osmium, 38oxometallic, 191

trinuclear, 94trinuclear, Os and Ru, 95

Cluster-containing monomer, 37, 94Clusters

AgmCn , 259

magnetic, 283metal-containing, 276oxohafnium, 279oxozirconium, 279

Coating, 170Coefficient

polarisation, 232refraction, 226

Coilpolymeric, 16, 197

Complexactinide (III), 173alkylcobalt, 107bimetallic, 167binuclear, 37, 68, 70binuclear ferromagnetic, 64binuclear methacrylate, 61, 66, 67centro-symmetrical, 69cluster, 96, 100dimeric, 152f -elements, 32fumarate lanthanoid, 29heteroligand, 32heterometallic, 29heteronuclear, 35, 61–63high spin octahedral, 63, 74intermolecular, 148intramolecular, 148itaconate, 28lantern type, 66lanthanoid, 30, 80lanthanoid propynoate, 96liquid crystal, 33macrocyclic, 70macromolecular, 147, 150, 227, 245macromolecular metal, 145metal-alkene, 88metal-containing, 238, 245metal-oleates, 271(meth)acrylate, 63, 67methacrylate, 65, 67mixed valence, 68monodentate, 58mononuclear, 33, 34, 37, 70multinuclear, 94, 95olefin, 30olefin-carboxylate chelate, 88oxocarboxylate, 35polychelate, 17

296 Index

polymer, 86, 100polymer-immobilized, 246polynuclear, 29, 35, 37, 152polynuclear heterometallic, 168protonated, 28self-organizing, 204styrene–arsenic sulfide, 106styrene-As2S3, 112supramolecular, 198tetranuclear, 29, 70tetranuclear methacrylate, 62trinuclear, isomorphic, 62

Composition azeotropic, 139 -Complexes, 85–87Condensation, 18, 278Configuration

bidentant-bridge (� � 1, 2), 4bidentant-chelate (� � 1, 1), 4heterotactic, 118isotactic, 118octahedral, 69planar, 76sin- and anti-, 57square planar, 68syn- and anti-, 80syn- and sin-, 80stereochemical, 117syndiotactic, 118tricapped trigonal prism, 62trigonal bipyramid, 68trigonal planar, 88

Constantchain transfer, 106complexation, 146copolymerization, 128, 131, 140copolymerization effective, 132dissociation, 28, 85, 155equilibrium, 85, 88, 146, 248exchange interaction, 74formation, 147–149, 154, 173formation successive, 148Huggins, 197ionization, 9, 15isotherm, 240Langmuir, 239pKa, 2, 15protonation, 155rate, 105, 109, 113, 266reaction rate, 138relative reactivity, 129, 140stability, 28, 86, 156, 162

macrocomplexes, 152, 154Weiss, 64, 74, 83

Contactsacetylene-acetylene, 96

Coordinationmetal-ligand, 4square pyramidal, 66, 76, 83trigonal planar, 86

Coordination modebidentate bridging, 67, 100bidentate cyclic, 58, 61, 89, 100bridging, 58chelating, 70, 100monodentate, 62, 68–70, 100polydentate, 66tridentate, 61tridentate bridging, 62

Coordination number, 58, 146, 153Copolymer

block, 19cluster-containing, 219cross-linked, 239graft, 19heterometallic, 182saponified, 19

Copolymerizationazeotropic composition, 139bulk, 138kinetics, 129, 134metal carboxylates, 128Q–e scheme, 129resonance stabilization, 129solid-phase, 282styrene with itaconic acid, 17suspension, 18transition metal acrylates, 134transition metal salts, 133unsaturated carboxylates Sn-containing,

132unsaturated carboxylic acids, 17unsaturated metal carboxylates, 141

Copper(II) chlorofumarate, 35Corona discharge, 19Cromium(II) acrylate, 34Cross-linking

intermolecular, 134Crystalline lattice, 122Curie–Weiss law, 64, 167Cycle

14- and 22-membered, 804- and 14-membered, 848- and 28-membered, 81catalytic, 4chelate, 77eight-membered, 87five-membered, 2

Index 297

four-membered, 80interchain, 195porphyrin, 246seven-membered, 76, 77, 80, 251

Cyclodimerization, 120Cyclohexene, 246–248Cyclohexenylhydroperoxide, 249Cyclopolymerization, 17Cytochrome, 252

Deactivationintramolecular, 116

Decarboxylation, 264, 268Degree

absorption, 239alternation, 139conversion, 114, 116, 149, 266cross-linking, 196, 233, 237crystallinity, 120dissociation, 107epoxidation, 180neutralization, 152, 159, 186, 187,

220, 233protonation, 154swelling, 233, 236

Dehydration, 264Density functional theory, 58Dextran, 172Diagram

copolymerization, 136Dialysis, 105, 153, 159Diastereomeric form, 120Dibenzoylmethane, 227Dibutoxybis(butylmaleate)titanium, 32Dicarboxylate

bis(trimethylstannyl) maleate, 36dibutoxybis(butylmaleate)titanium, 32maleate bimetallic, 34manganese, 33titanium, 31tributyltin maleate, 132

“-Diketonate, 33Diffraction, 268Dihydrogenmaleate, 74Dimerization, 152Dimethylaniline, 180Dipyridine, 33Divinylbenzene, 168, 195Dodecyl sulfonate, 180Dodecylamine, 261’; ’-Dimethoxydeoxybenzoin, 108

Ebullioscopy, 105Effect

chain cooperative, 148cross-linking, 219kinetic, 120, 121polarity, 129, 131reinforcing, 223stereo- and regiospecific, 120

Elastomer, 180, 220, 224, 225, 233Electroflotation, 238Electrolyte, 112, 149Elongation at break, 221, 223Enzyme, 246Epichlorohydrin, 18, 225Equation

copolymerization, 129copolymerization rate, 137Henderson-Hasselbac, 15Kohlrausch, 207Langmuir, 163, 239Mayo-Lewis, 128radical polymerization, 106, 114

Ethylenediamine, 107Ethylenediaminetetraacetate

sodium, 105Excitation energy, 228, 230Extracoordination, 207, 210

FactorDebye–Waller, 268enthalpy, 117exchange interactions, 84steric, 118topochemical, 120

Feracryl, 174Ferment

immobilized, 145Fermentation

Aspergillus terrus, 9Ferrites, 265Film

anisotropic, 279hybrid nanocomposite, 283hybrid thin, 278insulating, 283Langmuir–Blodgett, 10, 108, 279PE, 21polyacrylic acid, 259thin, 275ultra-thin, 168

Flori principle, 147Fluorescence, 230Fulvic acid, 23

298 Index

Fumaratechain, zigzag-shaped, 81chelate monodentate, 93Cu(I), 87polymeric, 84

Functionstructural, 68

Gas-discharge plasma, 19, 20Geometry, 71Glass temperature, 186Glass transitions temperature, 219, 220Glass-transition temperature, 184–186, 189,

196, 283

Halogenidemolybdenum, 95transition metal, 108

Heteroacidthio-, phosphonic, amino-, 7vinylbenzoic sulfonic, 7vinylsulfonic, 7

Heteropolyacids, 173Heterostructure, 273Humic acids, 171, 173

acidity degree, 24complexation, 24complexation of metal ions, 24structure, 23

Hydrohydrogen intramolecular, 70

Hydrogel, 235–238, 241, 244smart polymeric, 261

Hydrogen maleate, 70Hydrogenation, 114, 246Hydrogenmaleate, 75, 83Hydrolysis, 7, 17, 34, 278Hydroperoxide, 106, 248

cyclohexenyl, 249cyclohexyl, 246

Hysteresis loop, 283

Interactionantiferromagnetic, 63, 84, 183antiferromagnetic exchange, 182cooperative, 149, 168donor-acceptor, 136, 167electrostatic, 117, 151exchange, 63, 67, 74, 83ferromagnetic, 84

ferromagnetic intermolecular, 84hydrophilic, 149hydrophobic, 16, 149interchain, 182, 191interfacial, 222intermolecular, 139, 179, 192interplane, 198intramolecular, 74, 152intrapolar, 19ionic, 185, 186, 221, 260metal-metal, 67, 94multipolar, 230polar, 221polymers with nanoparticles, 260reversible, 108super exchange, 74Van der Waals, 197, 257

– -Interactions, 200Intercalation, 200Interchannel distance, 202Interpenetrating polymer networks,

194, 197”-Irradiation, 107, 128Ion pairs, 109Ionic pairs, 109Ionomer

aggregates, 217, 222aggregations, 181carboxylated, 179clusters, 189, 191composition, 179domains, 181, 221

diameter, 190radii, 190

ethylene-methacrylic acid, 2ethylenic, 183ion pairs, 181, 190liquid-crystalline, 185maleate-modified, 180microphase, 187, 190microstructure, 188model

core-shell, 180cylinder, 180multiplet-cluster, 180Yarusso-Cooper, 190

morphology, 181multipletes, 290multiplets, 181, 185, 189, 190structure, 181synthesis, 179

�-Irradiation, 238, 243Iron(II) fumarate, 35Iron(III) polymethacrylate, 120

Index 299

Irradiation, 83, 96�-, 60Co, 17UV, 19

Isomeracid

trans- and cis-, 8cis- and trans-, 78trans- and cis-, 8, 9’- and “-, 8

Isothermsadsorption, 243Langmuir, 239sorption, 239

Itaconatescoordination polymer, 83

Kaolin, 172, 235Kuhn segment, 16

Langmuir isotherm, 163Latex, 111Lauryl peroxide, 106Layered double hydroxides, 200Liquid crystal monomer, 121Liquid crystals, 290Liquid-crystalline monomer, 202, 208Luminescence, 228, 229, 231

Macrocomplex, 158, 159, 162, 166, 174bimetallic, 166

Macrocomplexes, 245–247Macrocycle, 93, 235Macromonomer, 235Magnetic moment, 63, 83, 84

effective, 64, 65, 74Magnetization, 283Maleate

acidic, 69bimetallic, 34, 76chain, zigzag-shaped, 79

Maleic anhydride, 32Materials

bilayer, 19composite, 19fluorescent, 231hybrid, 20hyper-absorbent, 232magnetic, 283metal-containing, 3nanostructured, 270, 279, 282organic-inorganic hybrid, 170

oxocluster hybrid, 277smart, 2, 17water-absorbing, 291

Matrixcross-linked, 201polyethylacrylate, 185polymer, 276polymeric, 181, 184, 185, 190, 208

Mechanism, 30cross-linking, 217diffusion, 162donor-acceptor, 106initiation, 115ion pair, 117ionic-coordination, 291monomer-drop, 111radical polymerization, 112radical-coordination, 291solid phase polymerization, 122zip polymerization, 204

Membrane, 22, 145carboxymethyl cellulose, 171ion exchange, 162liquid, 145

Metal acetylacetonates, 30Metal alkoxide, 32, 34, 35, 38

hafnium(IV), 34multinuclear, 92zirconium(IV), 34

Metal carboxylates, 1binuclear, 70cluster-containing, 37copolymerization, 128crotonates heterometallic trinuclear, 34dehydrated, 266diene, 290geometry, 57heterometallic, 34heteronuclear, 34liquid-crystalline, 120magnetic moment, 63monobasic, 2mononuclear, 68oxocluster, 34polymerization, 107saturated, 2, 38, 100self-assembling, 121solid phase polymerization, 122structure, 63, 154synthesis, 27, 29thermal polymerization, 122thermal stability, 264thermolysis, 263, 264trinuclear, 68

300 Index

trinuclear oxo, 88trans-2- and 3-butenoates, 126trans-2-pentenoates, 126unsaturated, 2–4, 39, 99, 105unsaturated thermolysis, 264

Metal chelates, 76Metal enzyme, 2, 4Metal polyacrylate, 107

IR spectra, 119molecular mass, 107stereoregular composition, 119syndiotacticity, 107

Metal protein, 88Metal-containing monomer, 245, 266

ATRP, 108liquid crystal, 121liquid crystalline, 108, 121liquid-crystalline, 203mesogenic, 201

Metal-protein, 2Metallopolymer

cross-linked, 118crystalline, 120methods of preparation, 1microstructure, 118molecular mass, 105, 109

Methacrylateyttrium, 35

MethodBeurrum, 147Fenske–Hall, 85Fineman–Ross, 129fitting, 268Gregor, 147Hill, 146Kelen–Tudos, 129laser light scattering, 260Mayo–Lewis, 129molecular mass determination, 105potentiometric titration, 155rare-earth probe, 181Scatchard, 146small angle X-ray scattering (SAXS), 181sol–gel, 277WAXS and SAXS, 183

Micelle, 165, 200, 290inverse, 273multinuclear, 273reverse, 111, 169rod-like, 273self-organizing, 204spherical, 273super-, 273

Microorganisms

Aconitum, 9Aspergillus terrus, 9

Micropores, 198Microstructure, 117, 118Model

chain conformation, 192Module

elasticity, 221relaxation, 185storage, 220

Molar conductivity, 63Molecular magnet, 283Morphology, 138

core-shell, 275

N ,N 0-Methylenebisacrylamide, 234N -Isopropylacrylamide, 236, 237N,N-Diphenyl-N 0-picrylhydrazyl, 109Nanocomposite

ferrite, 281hybrid, 276, 278, 279intercalated, 201metal-containing, 257, 263metallopolymer, 4, 100organic-inorganic hybrid, 4polymeric, 276polymeric hydroxyapatite, 275polymeric microgel, 274

NanocrystalsCoFe2O4, 272heterometallic, 257monodisperse, 270preparation, 271

Nanofibre, 275Nanofiller, 283Nanofiltration, 145Nanoparticle

aggregation, 4blue silver, 258CdS, 261, 276CdSe, 280CoFe2O4, 281copper, 258Cu2S, 271formation, 257formation in situ, 275gold, 258magnetite, 275metal, 257, 273, 274, 291metal-containing, 263nucleation, 267, 271nucleation heterogeneous, 268semi-conducting, 273

Index 301

silver, 258size, 259size distribution, 263stabilization, 257titanium (IV) oxide, 259ZnS

Mn, 258Nanopowder

ferroelectric, 283Nanosphere, 276Nanowire, 259, 271Network

three-dimensional, 82Neutron diffraction method, 69Nickel tetracarbonyl, 8N -dodecylacrylamide, 203Number

Abbey, 227

Organismanimal, 174living, 145

Orthotitanatesalkyl, 31

Oxidation, 246–248, 266Oxocarboxylate, 28, 89, 90

heteronuclear, 93polynuclear, 34

zirconium, 34trinuclear, 28unsaturated, 92

Oxoclusters, 4, 35titanium(IV) methacrylate, 35yttrium(III) methacrylate, 35

Parameterantiferromagnetic exchange ineraction, 74cooperativity, 149copolymerization, 130, 132elemental lattice, 125kinetic, 105, 106, 112, 138, 248photoageing, 232polarity, 129Q and e, 131, 134relative reactivity, 129, 134resonance stabilization, 129SAXS, 190structural, 69thermodynamic, 149, 160

Pectin, 172Perovskite, 283Phase

hexagonal, 202hexagonal meso-, 202liquid-crystalline, 202thermotropic, 202

Phenanthroline, 80, 84, 97Phenantroline, 33, 81, 227Photoelectron, 268Photoluminescence, 230Photopolymerization, 3, 120, 121, 201, 217Piperazine, 81, 82Polelectrolyte, 262Poly(p-phenylenevinylene), 201Poly(ethylene oxide), 108Polyacid, 150, 157

affinity toward metal cations, 150complexation, 147ionization, 152luminescent ability, 229macroligand, 150natural, 290polyacrylic, 145, 170, 238

triple metal salt, 174polymaleic, 173stereoregular, 159

PMAA, 159syndiotactic, 160

Polyacids, 15–17cross-linked, 18polyacrylic acid (PAA), 15, 16polyetylacrylic, 16polymaleic, 17polymethacrylic acid, 15, 16stereoregular, 17

isotactic, 17syndiotactic, 17

stereostructure, 18Polyacrylate

calcium, 110copper, 117magnesium, 110sodium, 111strontium, 110

Polyacrylic acidsyndiotactic, 118

Polycondensation, 1Polyelectrolyte, 15, 108, 151, 173

cross-linking degree, 16viscosity, characteristic, 16weak, 16

Polyethylenepolyamine, 18Polygalacturonic acid, 172Polymer

anisotropic, 108, 120bio-degrading natural, 235

302 Index

branched, 20carboxyl group containing, 145carboxyl-containing, 17carboxylic-containing, 1cluster-containing, 95cluster-dopped, 283coordination, 75, 78, 79, 83, 153coordination two-dimensional, 94cross-linked, 20, 120framework, 76, 79framework, interpenetrating, 80interpenetrating network, 194ion-containing, 10, 180, 190, 221ionomeric, 185linear, 69, 97liquid-crystalline, 258macroporous, 20metal-containing, 1, 89, 182, 227

morphology, 191micronetwork, 19microstructure, 187molecular mass, 15, 105morphology, 197natural, 171network, 19regular, 117sulfoionogenic, 179syndiotactic, 117three-dimensional, 78, 80three-dimensional coordination, 69, 77, 79,

97three-dimensional network, 192water-soluble, 10, 235

Polymerization”-induced, 107, 120”-initiated, 125acrylic acid, 114activation energy, 113alkali metal methacrylate, 117anionic, sodium methacrylate, 117ATRP mechanism, 107, 108block, 251bulk, 15, 118, 186chromium acrylate, 112cobalt acrylate, 113, 114, 118conditions, 112copper acrylate, 113, 116emulsion, 107, 111

photo-induced, 111gaseous-phase, graft, 21graft, 19–21, 211, 234ionic pair, 109low temperature, 118maleic acid salts, 105

matrix, 204matrix synthesis, 21metal (meth)acrylate, 112metal acrylates, 106, 107, 109, 114metal carboxylates, 107metal-containing monomer, 109methacrylic acid, 15nickel acrylate, 118order of reaction, 112photo-induced, 107, 123

emulsion, 111photochemical, 278post, 123, 124radical, 105, 106, 108

atom transfer, 108bulk, 118ionizing monomer, 109living chain, 108low temperature, 107rate, 107, 113salts of unsaturated carboxyl acids, 109stereochemistry, 117transition metal (meth)acrylates, 112

rate, 105sodium acrylate, 122solid-phase, 121, 122, 124, 182, 211, 264,

283barium methacrylate, 122

thermal, 208topochemical, 127topochemical postulate, 126transition metal acrylate, 113unsaturated metal carboxylates, 122UV-induced, 107zinc acrylate, 113

Polymethacrylic acid (PMAA), 16atactic, 118

Polysaccharides, 22Potentiometric titration, 28, 147, 151,

155, 159Principle

all or nothing, 149Process

metabolic, 2Pyridine, 88

Q–e scheme, 141Quantum chemical calculation, 58Quantum dots, 261, 274Quantum yield, 230Quenching, 32, 155, 227, 229

Index 303

Radical polymerizationlow temperature, 119

Radionuclide, 241, 243Radius

ionic domain, 184Radius cation, 131Radius ionic, 129Rare earth elements, 157Reaction

carbonization, 267catalytic isomerization, 35chain transfer, 106complexation, 96, 148condensation, 34conditions, 28cyclization, 195esterification, 35esterification, trans-, 32etherification, 193, 251exchange, 33, 275exothermic, 113hydrogenation, 291hydrolysis, 34hydrosylilation, 291hydroxylation, 252intermediate, 30intramolecular chain termination, 208intramolecular cyclization, 30isomerization, 291ligand exchange, 30, 33, 34liquid-phase, 19model, 147, 246monomolecular termination, 116neutralization, 27oxidation, 8, 88, 266

gaseous-phase, 8oxidative addition, 37oxidative carbonylation, 7parallel reversible, 30polymer-analogous, 94polymeranalogous, 1, 17, 145, 180, 290sol-gel, 34solid phase, 127topochemical, 126, 128trans-addition, 35x-ray induced, 127

Reagentacidic, 107polymer, 149, 151

Reduction potential, 116Relaxation time, 119, 120Resin

cation-exchange, 18epoxy, 225

ion-exchange, 18ion-exchange, cation, 18

Rhodamine, 232Ribonuclease, 16Rubber

ethylene-propylene, 223ethylene-propylene-diene, 223, 224ethylene-vinyl acetate, 223nitrile-butadiene, 225styrene-butadiene, 223vinyl-acetate, 223

™-solvent, 16SAXS, 184, 187, 188, 190

ionic peak, 187Schiff bases, 107Shear viscosity, 222Shiff bases, 35Shift Bathochromic, 211Shift hypsochromic, 208Silica gel, 260Sorbent, 239, 244, 291

polymeric, 238Span, 111Spectroscopy

13Cf1Hg NMR, 42”-resonance, 2891H NMR, 38, 43, 461H-NMR, 41–43, 4513C NMR, 213C vs. 1H NMR, 881H NMR, 881H � 13C NMR, 4dielectric, 119, 181electron, 64

diffusion reflection spectra, 64electron transitions, 65

electronic, 289EPR, 106, 122, 124, 181EXAFS, 2, 91, 93, 181, 268FTIR, 44, 48, 49, 51”-resonance, 57IR, 2, 41, 43–45, 47, 58, 62, 70, 89, 95,

119, 156, 188asymmetrical and symmetrical

vibrations of the COO ion, 58stretching frequencies of COO� –

groups, 157NMR, 95Raman, 181Raman and IR-, 181UV, 161UV-vis, 48, 57

304 Index

X-ray photoelectron, 271XPS, 116

Spherulite, 222Standard potential, 208Structural, 59Structure

alternating, 134alternation, 134amorphous, 192atactic polymer chain , 119brushes, 168chelate, 193cluster domain, 182comb shaped polymer, 119cross-linked, 118, 193, 194crystal, 78, 83, 84, 93, 126diamond, 97dimer, 36, 97fiber, 76guest–host, 198hexacoordinated, 2hexagonal columnar, 121isotropic, 121lamellar, 202lantern type, 199mesormorphic, 121microporous, 199molecular, 69, 70, 92monomeric, 70network, 119oligomer, 67oligomeric, 35oxocluster, 93oxypolynuclear, 125planar, 69polymer, 67, 74, 77projection, 66rod-like, 16, 202staphylonuclear, 95statistical, 134stereoregular, 18, 21, 22, 290supramolecular, 21, 68, 150,

179, 213syndiotactic, 192tetracoordinated, 2tetrameric, 64three-dimensional, 29, 83three-dimensional network, 119two-dimensional, 76, 83zigzag, 127

Structuring of water, 16

Subacid, 18, 19Supramolecular chemistry, 4Surface-active substance (SAS), 16Swelling

equlibrium, 237Symmetry

D2h and D4h, 153Synthesis

bottom up, 263conditions, 77hydrolysis, 34hydrothermal, 29, 289metallopolymers, of, 105methacrylate Mn12, 29non-aqueous medium, 38organometallic, 96polymer-assisted, 281salts, unsaturated carboxylic acids, 27sol–gel, 283sol-gel, 34solid-phase, 201stereospecific, 117top-down, 263

Systembiological, 145, 172biomimetic, 1ion-polymer, 146natural, 145oxidation-reduction, 19

Tearing strength, 221Technique

atom transfer radical polymerization,275

inverse micelle, 280Langmuir–Blodgett, 280magnetic resonance visualization, 232sol–gel, 283stopped-flow, 155

TEM, 263, 272Tensile strength, 221, 223, 225Tercopolymer, 231Termination, (intramolecular deactivation),

116Terpolymer, 139–141, 219, 226,

230, 235Terpolymerization, 138, 139tert-Butyl hydroperoxide, 106Tetraalkoxide (orthotitanates), 32tert-Butyl hydroperoxide, 105

Index 305

Thermolysis, 268, 270kinetics, 266metal acrylates, 270solid-phase products, 268

Transmission electron microscopy (TEM),190, 191

Tributyltin acrylate, 106Tributyltin methacrylate, 118Trimerization, 120tris(Acetylacetonate) terbium, 30

Ultrafiltration, 145, 238

Vesicle (micelle-like aggregates), 204Viscosity, 106

characteristic, 159, 160Vulcanization, 222, 224, 225, 233

Wide angle X-ray scattering (WAXS), 183,184

X-ray diffraction, 2, 58, 65, 121, 269Xerogel, 233

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