macromolecules containing metal and metal-like elements (metal-coordination polymers) ||...

1

CHAPTER 1

Introduction to Metal-Coordination Polymers

Charles E. Carraher Jr.

Department of Chemistry and Biochemistry, Florida AtlanticUniversity, Boca Raton, Florida

Charles U. Pittman Jr.

Department of Chemistry, Mississippi State University, Mississippi State, Mississippi

Alaa S. Abd-El-Aziz

Department of Chemistry, The University of Winnipeg,Winnipeg, Manitoba, Canada

CONTENTS

I. INTRODUCTION 2

II. POLYMER SOLUBILITY 3

III. POLYMER FORMATION 5

IV. COMPLEX STRUCTURES 14

V. SCHIFF BASE POLYMERS 19

VI. PORPHYRIN SYSTEMS 21

Macromolecules Containing Metal and Metal-Like Elements, Volume 5: Metal-Coordination Polymers, edited by Alaa S. Abd-El-Aziz,

Charles E. Carraher, Jr., Charles U. Pittman, Jr., and Martel Zeldin.Copyright © 2005 John Wiley & Sons, Inc.

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VII. PHTHALOCYANINE SYSTEMS 23

VIII. PYRIDINE AND RELATED SYSTEMS 24

IX. MISCELLANEOUS RING AND MULTISITE SYSTEMS 27

X. COORDINATION NETWORKS CONSTRUCTED FROMORGANOMETALLIC LIGAND SPACERS 28

XI. REFERENCES 34

I. INTRODUCTION

In this volume, a coordination polymer is defined as a polymer that contains ametal, which coordinates to Lewis base-like ligands, and these coordination com-plexes are part of the overall polymer. Many biologically important metal-containingpolymers are coordination polymers, which includes metal-containing macromole-cules in the human body such as transferrin and hemoglobin (iron), xanthine oxidase(molybdenum), hemovanadin (vanadium), carbonic anhydrase (zinc), and hepa-tocuprein (copper). Coordination polymers also play an essential role in plants wherephotosynthesis, via chlorophyll, lies at the heart of energy use to build biomass.

There are a variety of ways of defining coordination compounds. This chapterwill be somewhat restrictive, requiring a material to exist in polymeric form in solu-tion to be considered a coordination polymer. Thus, compounds such as lead chlo-ride that are polymeric as solids from X-ray studies, will not be considered ascoordination polymers since in solution they are monomeric or they exist as distinctmonomers. Thus, a number of organolead halides exist in the solid as collections ofsupramolecular assemblies, but in solution exist as monomeric compounds. Onesuch structure is trimethyllead(IV) iodide, 1, which exists as a zigzag chain confor-mation in the solid phase.1

The term “classical complexes” is employed to describe the materials coveredin this volume.2 Classical complexes include ligands with a discrete electron popu-lation bound to a metal with a well-defined oxidation number. This eliminates com-plexes where the metal–ligand bonding is highly covalent and/or multiple bonding.Thus, metallocenes such as ferrocene are not covered in this chapter. Further, usingthis logic, organometallic compounds, such as dibutyltin dichloride, are eliminatedfrom consideration in this chapter.

CH3

Pb

CH3

CH3

Pb

H3C CH3H3C CH3

PbH3C

CH3Pb

H3CCH3

CH3

2 Introduction to Metal-Coordination Polymers

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Coordination polymers hold a special place among metal-containing poly-mers. These materials were first emphasized in the late 1940s–1960s, when theywere the subjects of widespread research activity. Much of this effort was supportedby the U.S. government through activity headquartered at Wright-Patterson Air ForceBase, just outside of Dayton, OH. The effort was largely aimed at the production ofmaterials with outstanding thermal stabilities for use in the emerging space program.This activity stemmed from the observation that some organometallic coordinationcomplexes were thermally stable from 200 to 400C and the hope that the thermalstability of coordination polymers would greatly exceed this stability. Unfortunately,polymeric analogues did not generally give more thermally stable materials. Oftenthe polymeric versions underwent thermally induced degradation at lower tempera-tures. Many outstanding polymer and inorganic chemists were involved in this effortincluding Marvel and Bailor.

The bonding between the ligand and the metal ion is generally formed by atypical Lewis acid–base reaction where the Lewis acid, A (acceptor atom), and base,:B (donor atom), form a coordinate bond, A:B. An example coordination compoundmade from ethylenediamine (en) and nickel in sulfate solution is Ni(en)2SO4. Here,the “en” is a multidentate or a chelate ligand. The nickel complex is a chelate com-pound, and the cation is a chelate ion. Further, the number of binding sites used bythe chelating ligand can be two, bidentate; three, tridentate; four, quadridentate; five,quinquedentate; and six, sexadentate.

The reason metals are included into coordination polymers is to take advan-tage of the chemical and/or physical properties, which the metal may add to thepolymer. Further, introduction and greater in-depth coverage of coordination com-pounds is given in general and specific texts.2–9

II. POLYMER SOLUBILITY

A general problem with coordination polymers is their lack of ready solubilitylimiting both the use and characterization of the products. Even when solubilized,solubility is often accompanied by polymer degradation, rearrangement, solvation,and so on. Further, because of the difficulty of obtaining single crystals of coordi-nation polymers, few X-ray studies have been carried out so structural characteriza-tion of coordination polymers is often difficult and incomplete.

The following is a brief review of comments related to coordination polymersas described by Bailor.10 These principles are generally applicable.

• Little flexibility is imparted by the metal ion and within its immediate environment.• Metal ions only stabilize those ligands in the immediate vicinity, thus the chelates

should be stable and close to the metal atom.• Polymers must be designed specifically for the properties desired, such as solubility.• Metal–ligand bonds have enough ionic character to permit them to rearrange more

readily than typical “organic bonds”.

Polymer Solubility 3

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• Flexibility often increases as the covalent nature of the metal–ligand bondincreases.

• The coordination number and stereochemistry of the metal ion or oxide dictatepolymer structure.

• Solvents that are employed to solubilize coordination polymers should not formstrong complexes with the metal atom or chelating agent. They could be incorpo-rated into the polymer structure or prevent desired subsequent reactions fromoccurring.

Archer11 and Carraher et al.12 described attempts to increase the solubility ofmetal-containing polymers including coordination polymers. Archer lists the follow-ing as approaches to overcoming solubility problems.

1. The presence of bulky ligands minimizes stacking interactions providing solubleplanar divalent d8 polymers.

2. Eight-coordinate centers that tend to be nonrigid have been used for synthesizingsoluble polymers.

3. Octahedral coordination centers with a metal ion surrounded by three bidentateligands can be made to produce soluble polymers.

4. Strong solvent interactions with metal coordination centers assist in the solubil-ity of metal-containing polymers.

5. Small tetrahedral centers allow for the production of soluble polymers.

With respect to the use of strong solvent interactions, item 4, Archer,11 ourgroup,12–19 and others have found that the solvent molecules may actually act as aligand complexing the metal site as solution occurs. This additional complexing canoccur through substitution of an existing ligand or through expansion of the coordi-nation number.

Other items that have aided solubility include

• Use of nonsymmetrical ligands and metal sites.11–19

• Use of flexible units in the polymer backbone including dimethylsiloxane, meth-ylene oxide, ethylene oxide, and methylene units.18

• Use of strongly polar–dipolar aprotic liquids that also can coordinate to metalcenters. Examples include dimethyl sulfoxide (DMSO), dimethylacetamide (DMA),dimethylformamide (DMF), hexamethylphosphoramide (HMPA), and NMP (N-methylpyrrolidone).11–19

• Use of flexibilizing units as side chains to both increase the flexibility of the poly-mers and to discourage orderly packing and crystalline formation.

• Polymer isolation from rapidly stirred systems before the polymer becomes a solid.The precompletely solidified polymer still retains some reaction solvent molecules.19

• Addition of a plasticizing agent as polymer formation occurs.• Use of bulky and extended groups that tend to inhibit crystal formation.• Through heating.

The presence of alkyl groups tends to increase solubility in organic solvents whilephenyl and rigid groups reduce polymer solubility. Solubility in polar solvents often is


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enhanced by polar units in the polymers while the absence of polar units enhances thesolubility in nonpolar liquids.

III. POLYMER FORMATION

John Bailor was kind enough to write a review for us on coordination polymersin 1978. Readers are referred to this book for Bailor’s review of older material.19

Coordination polymers were reviewed in Volume 1, Chapter 5 of this series.21

Related topics will be briefly covered.20

There are three main approaches to metal-containing coordination polymersynthesis.19,21 They are coordination polymer formation through:

1. Complexation with ligands that produce a polymer backbone containing the lig-and and metal in the backbone.

2. Chelation of metals to an already formed polymer that contains complexing lig-and moieties.

3. Polymerization of ligand groupings that already complex the metal.

Each of these avenues to metal-coordination polymers is covered in greaterdepth in various locations throughout this volume.

There are numerous coordination complexes that can be defined in the solidstate as polymeric materials. X-ray diffraction studies show that various componentsof the structure are sufficiently close enough to one another to be called polymers orsupramolecular. One such example is Prussian Blue, a mixed-Fe(II) and -Fe(III)three-dimensional (3D) solid structure, where each iron is octahedrally coordinatedby six cyano ligands. Upon dissolution, a polymeric, high molecular weight speciesno longer exists. As noted before, this class of complexes will not be emphasized inthis chapter.

1. Complexation with ligands that produce a polymer backbone containing theligand and metal in the backbone. Here ligands simultaneously attach them-selves to two or more metals. There is a vast array of structures that have beenformed through ligand attachment to a metal. If the complexing groups are some-what removed from one another, then there is opportunity for larger structures tobe formed including macromolecular structures. These ligands can be chelatingwith several complexing sites acting in concert as in the rubeanate bis-chelatingagents during the formation of structure 2.22

S+

Ni2 −

S

2

+

Ni2 −

HNR

RS+

HN

NH

NH

Ni2 −S+

R

R

Polymer Formation 5

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The ligand can be composed of two “widely” spaced mono or chelating complexinggroups as was used to complex the uranyl ion22–25 forming general structures suchas 3. Reaction with disodium terephthate gives polymer 4.


nC

O

O

C

O

U

OO

3

4

H2O

OH2O

R

C

O

O

C

O

U

OO

H

CO2− + uranyl ion

Product of the uranyl ion and the salt of terephthalic acid

2O

OH2O

n

R−O2C

+1/X

[ Ru (R2bpy)Cl3 ]xethanol/water

N N

R R

Ru NN

N

N N N N

N

N

N

Ru

N N

R R

N

N N

N N

N Ru

N

N

N

N

R R

R

RR

5

6

H , Ph−

N

N

N

N

N

N

n/2

(2n + 2)+

(2n + 2)Cl −

Where bpy = 2, 2′ - or 4, 4′ - bipyridine

The synthesis27 of the soluble, ruthenium-containing octahedral polymer 6from the bis-chelating rigid ligand 5 is a typical example of coordination polymer-ization where a ligand binds to two different metals. Ruthenium is an integral andnecessary part of the polymer backbone in 7.26

Polymers are formed from single attachments by at least two coordination siteson the same ligand molecule to two metal atoms. Thus, coordination polymers areenvisioned to be important alternatives to small coordination complexes such as cis-platin in the treatment of cancer.27–34 The product polymer, 7, from tetrachloroplatinateand 1,6-hexamethylenediamine is shown below. These products were reviewed inVolume 3 of this series.

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In some cases, when the ligands can bind to a metal, single and multiple bridgesare formed leading to polymers. Block et al. prepared many products of this kindwhere the metal ions are linked together by substituted phosphinous anions.35

Structures 8 and 9 are examples. High molecular weight polymers were achieved andthese were among the Wrst coordination polymers to exhibit good solubilities. Themetals Al, Be, Co, Cr, Ni, Ti, and Sn were used. Commercial film products with highthermal stabilities (to 450C) were made. The chromium(III) polyphosphinates wereused in high-pressure silicone greases.

Polymer Formation 7

NH2NH

7

H2N (CH2)6 NH2 + PtCl4−

2

Pt

Cl Cl

n

O

PR R

R R

M

OP

O

M

O

O P O

R

M = Al, Be, Co, Cr,Ni, Ti, Sn

R rnM

8 9

OP

R R

OM

OP

R R

Some of these coordination polymers are linear (e.g., 8) with –(–M–O–P–O–)–repeat units while others exhibit the bridging shown above in 9.

An excellent example of polymer formation by reacting a bis-chelating ligandwith metal ions was provided by Chen and Archer.36,37 Trivalent lanthanide nitrateswere reacted with the sodium salts of bridging tetradentate Schiff-based ligands 10and 11 to generate polymers 12 and 13 in DMSO. Dimethyl sulfoxide was able tosolubilize both the lanthanide nitrates and the ligand salts. Importantly, DMSO isable to dissolve the polymers produced, which allows the formation of soluble, highmolecular weight products. The lanthanide ions used (YIII, LaIII, EuIII, GdIII, andLuIII) are expected to be very labile. However, these polymers are stable in solutionand do not break down into low molecular weight species. The key to this stabilityis the tetradentate nature of the binding, which holds each ligand to the metal ion. Inorder to fragment a chain, all four binding sites between the ligand and metal mustbe simultaneous broken. Each metal ion is eight coordinate. These eight-coordinatecenters are conformationally nonrigid and conformational fluctuations enhance thesolubility and decrease the tendency for regular packing of the polymer chains dur-ing solidification. Molecular weights of 21,600 and 18,500 were obtained using nuclearmagnetic resonance (NMR) methods for M Y and Eu, respectively.

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N

N

4Na+

10, x= −11, x= −CH2−

12, x= −13, x= −CH2−

X

M= YIII,LaIII

EuIII,GdIII,

LuIII

N

M(NO3)3

DMSO

N O−

O−O−

O−

N

N O

O

M

N

N

n

O

O X

RM

E+ Mn+

D

R n

M

R n2 R n

R nR n

CM

B

+ Mn+

+ Mn+

Rn

M

An

R+ Mn+

+ Mn+

nR

n+

n

nRR n

Mn

R2

2. Chelation to an already formed polymer that contains complexing ligandmoieties. Polymers, which have chelating ligands, either in the backbone or pen-dent to the backbone, can capture metal ions leading to coordination polymers.Rehahn38 divided this class of polymers into three subclasses, A–C shown below.One can imagine a large number of possibilities for each of these classifications.For example, the ligand in each case could have a variety of types of bindingsites. It could have mono-, di-, tri-, tetra-, or other polydentate sites. Furthermore,type A and C subclasses could actually form so as to cross-link different chainstogether, giving network polymers of the types D or E. In A, a metal ion has beenchelated to ligand sites all lying along the backbone. In B, a cyclic chelatingagent such as a porphyrin is in the main chain and chelates a metal. A pendentligand along a polymer chain can capture a metal ion as shown in C. If two pen-dent chelating ligands are required, cross-linking can give D and E is formed ifthe chelating sites are along the main chains of two polymer molecules.

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The ligand-containing polymer can be as simple as the salt of poly(acrylicacid), 14,39,40 or poly(vinyl pyridine). It can be more complex as with polythiosemi-carbazides, 16.41,42 The salt of polyacrylic acid reacts to complex uranyl ions giving15, which is analogous to the formation of polymer subclass C. The reaction of 16,on the other hand, binds Cu2 to the backbone. Thus, generation of 17 is an exam-ple of forming a polymer of the subclass A. Another example of this subclass resultsfrom the reaction of poly[teraphthaloyl oxalic-bis(amidrazone)], 18, with zinc ions.Chelation produces the thermally stable fiberous polymer 19. Products derived frompreexisting polymers, such as the salt of poly(acrylic acid), will contain severalstructures including the chelated products depicted below and unreacted units.

Polymer Formation 9

R

R

OO-

RR

OO

U OO

RR

O O

Na

14

Repeat units from reaction ofSodium poly(acrylic acid) and the uranyl ion

Copper (II) polythiosemicarbazide

16

18 19

17

15

+

OH2

OH2

Cu2+ + N N

S

N

H

S

N

H

R1

R

NH

R1

NH

S

NN

N

CuS

N NR

NR

R

H H

n+ 2H+

N NN

H2N NH2

N

O O

n

H HN

Zn

N N

OO

N

H2N NH2

n

Zn2+

Structure 20 is formed by reacting a copolymer with PtCl4 in an attempt toform water-soluble products.43,44 Here, the tetrachloroplatinate reacts almost exclu-sively with the amine functional units forming a platinum-containing structure thatexhibits anticancer activity.

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Carraher and Xu45 created a number of simple chelation polymers, 21, from reac-tion of zirconyl chloride with poly(acrylic acid) for the purpose of depositing Zr and Mgon a molecular level to form high strength Mg–PSZ ceramics. The approach was suc-cessful and allowed the synthesis of a number of high-strength advanced ceramics.

Styrene–divinylbenzene resins functionalized with diphenylphosphino moi-eties have been widely used to prepare polymer-anchored “homogeneous catalyststhat function as heterogeneous catalyst beds”. This work was pioneered in the late1960s and early 1970s by Pittman and others.46–86 Several reviews are available towhich readers are referenced.46–50,57,58,72–75 A very important aspect of these coordina-tion polymers was the availability of reversible ligand dissociation–association equi-libria with the metal center that permitted the tailoring of catalytic activity in severalcases. For example, the reaction of diphenylphosphinated styrene–divinylbenzeneswellable polymer beads with (PPh3)3RhH(CO) gave the polymer-immobilized versionof the homogeneous catalyst, 22a.47,49,54–66 These resins catalyzed the hydroformylationof olefins.47,60,61,66–68 Within the 3D cross-linked matrix of the polymer, the PPh2 lig-and equilibria can be varied enormously by changing the P/Rh ratio, the loading of–PPh2 in the resin, and the resin’s cross-link density. This, in turn, was used to con-trol the normal/branched product ratio, which depends on the predominant rhodiumcoordination state. Other examples of selectivity72,77,78,84,85 and rate62 enhancementshave been observed.

R

R

OO

Zr

R

21

R

O O

O

RR

NH2 NH2 S

O−

O O

K+

Pt

Cl

20

Cl


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Polymer Formation 11

PP Ph + (PPh3)3RhH(CO)2

CHO +R

CHO

P RhH(CO)Pn

Ph2

P RhH(CO)P

18 Electron 16 Electron

14 Electron

Ligand equilibria within the polymer matrix

3Ph2P RhH(CO)P

2Ph2PP Ph2 +

P RhH(CO)P Ph2PP Ph2 +

P

R R

= Styrine / Divinylbenzene

Normal Branched

H2 / CO

22a

22a

Polymer-anchored catalysts were devised to mimic many homogeneously cat-alyzed reactions while simultaneously permitting many of the advantages of het-erogeneous catalysts to be applied. For example, polymer-anchored catalysts can beused as fixed beds and reagents can be continuously pumped through them. Morenovel uses included the simultaneous use of two mutually incompatible catalystcenters in the same reactor. If two different metal centers were not stable togetherin the same solution (e.g., the metal–ligand site of one type of catalyst would reactwith the second type of metal–ligand site) they could become immobilized on sep-arate polymer beads so that these sites could not encounter another to react. Severalexamples of using two polymer-anchored catalysts, which are “site isolated,” haveappeared.46–49,54,55,59,60,65,76 These beads could be mixed together in the same solventand reaction vessel and multistep reactions could be carried out as schematicallynoted below. The immobilization of catalytic metal sites on the resins, allowedeffective site isolation of the different types of catalytic metal centers from eachother. Thus, “one-pot” multistep catalytic reactions became possible.

Another aspect of coordination chemistry was used to advantage in this polymer-supported catalyst development. The immobilization of ligand–metal complexes withina polymer matrix reduces the mobility of ligand–metal species during the reaction.In some reactions, especially those involving Pd(0) catalytic centers, insoluble andinactive metal-containing species form in solution and precipitate, thereby slowingthe rate and lowering productivity and turnover frequency. By reducing mobility of

LxM2LxM1

PA B +−++ CA B C

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N NC

N

NN

N Ru2+

N NCO

O

R O C

O

O R O C

O O

x y

2 Cl−

O R OC

O

N N

Ru(bpy)2(OTF)2.(acetone)2

C

O23

24

22b

such catalytic sites within a resin, the catalytic lifetime of the system can be increased.The selectivity and original reaction pathway that would be induced by a homoge-neous version of that same catalyst were also preserved.63,64,69,79

Photochemical generation of active catalytic sites on polymer-immobilizedphosphine-coordinated iron carbonyl complexes has been reported.76 Excited-stateinduced phosphine ligand versus carbonyl group dissociation at low temperaturesproduced catalytically active centers. These active centers catalyzed olefin isomer-izations and alkylsilyl hydride additions.

The polymer-immobilized transition metal catalyst field is continuing its rapidgrowth as evidenced in more recent reviews.57,73–75 A pyridine-containing polymer,22b, has been used to coordinate a ruthenium complex, 23, giving the ruthenium-containing polymer 24.87

1 or 2PPh2 Fe(CO)3 or 4 PPh2 Fe(CO)2 or 3

−Chν

hν

O1 or 2

1 P

Photochemically generatedpolymer-anchored catalysts

Ph2 Fe(CO)3

Metal ions are often employed to cross-link two polymer chains, which wasillustrated earlier in the generalized structures D and E. Ionomers are another class ofthis as a broad grouping. Ionomers can form clusters of salt centers, which are quitesmall, or larger domain-sized aggregates. These provide effects similar to cross-linking.Strictly, the ligand is an anion and the metal is a cation center in sulfonate ionomers,so they represent the extreme ionic end of the coordination scale. Structure 25 issuggested for chelation of copper(II) salts with poly(vinyl alcohol) (PVACu2)upon mixing and subsequent modification by I2 doping of films of this product. Thesefilms are conductive with surface conductivities on the order of 103 Ω-cm2.88

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A second example is the cross-linking of polyethyleneimine through the intro-duction of a platinum-containing moiety.89–91 These products (see 26) exhibit goodanticancer activity and were described in Volume 3 of this series.

Carraher, Jiang, and Baird92,93 recently described the synthesis of a new ligand-containing polymer derived from poly(vinyl alcohol). The chelating ligand site isformed from the nucleophilic aromatic substitution by poly(vinyl alcohol) ontonitrophthalonitrile as shown below.

NH

PtCl

ClN

26

H

OH

25

OH HO

HO

Cu

I

I R

R

R

R

Polymer Formation 13

n

RR

O

N

N

27

n

N

N

N+

O−

O

RR

OH

K 2CO3

This product is then reacted to form poly[5-(1,3-bis(2-pyridylimino)-isoindolyloxy)ethylene], PBPIE, 28. Polymer 28 contains strongly chelating pendenttridentate ligands.

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NH

28

NN

NN

PBPIE

OR

R

n

n

N

N

Copper chelated "claw" portion of PBPIE

29

N N

NCu+

O

PBPIE was reacted in solution with various metal ions or through heating ofthe solid polymer. The structure for the copper(II) chelated polymer is shown in 29.

IV. COMPLEX STRUCTURES

A plethora of coordination polymeric shapes have been synthesized containingmetal atoms. Along with the “simple” linear and bridged structures shown before,more complex structures have been formed including dendrites, starbursts, rods,sheets, braids, coils, and shish kebabs.

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Early work included the efforts of polymer chemist, Carl “Speed” Marvel, andinorganic chemist, John Bailor, who demonstrated the marriage of polymer chem-istry and inorganic chemistry could be binding and produce interesting offspring.This marriage is illustrated by coordination polymers. Complex sheets and/or flat-bridged structures were reported in the 1950s by Marvel and Rassweiler94 andDrinkard and Bailor.95 Bailor reported that the reaction of pyromellitic dianhydride,Cu(II), and urea in the presence of a catalytic amount of ammonium molybdate pro-duced oligometic copper phthalocyanine linear bridged product, 30, that may well

Complex Structures 15

N

N NN

N

N NN

Cu

COOHHOOC

HOOC

HOOCN

N NN

N

N NN

Cu

COOHHOOC

N

N NN

N

N NN

Cu

COOH

COOH

HOOC COOH

N

N NN

N

N NN

Cu

HOOC

HOOC

CO

31

OHHOOC

N

N NN

N

N NN

Cu

COOHHOOC

HOOC

H

Linear

30

OOC

2–5

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32

O

OO

O

O

O O

OFe

O

OO

OFe

O

O O

OFeFe Fe

N

N

NN

MN

N

N

N

N N N N

N

N

NN

MN

N

N

33

N

N N

N

N

NN

MN

N

N

N

also have the more sheet-like structure, 31.95 Characterization was difficult withmajor problems of even obtaining molecular weight data.

Sheet-like structures, 32, were made through reactions of Fe(II) with 2,5-dihydroxybenzoquinone in basic media.96

Stacked or sandwich coordination products have been reported. These includeshish kebab-like structures. A metal phthalocyanime structure with bridging pyrazinegroups resembles a shish kebab structure with the face-to-face phthalocyanines act-ing as the stacked units and the pyrazine and metal atoms moieties as the skewer orspacing units, 33.97

Polymer 34 illustrates a coordination structure containing Rh–Rh bonds in themain chain coordinated on either end of this unit to a pyridine nitrogen.98 However, anorganometallic ferrocene unit is also connected so that iron is also an essential part ofthe backbone. Surrounding the Rh–Rh axle-like bond are coordinated octanoic acids.These form a paddlewheel-like structure with four solublizing, flexible heptyl groups,which also act to inhibit crystal formation.

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A similar structure, 35, is formed upon incorporating a zinc porphyrin into abackbone that contains “whole-chain” resonance and side-arms that encourage solu-bility and inhibit crystal formation.99 Incorporation of different substituents (electrondonating or accepting) on the aromatic rings alters the electronic properties of thesematerials.

A complex bridged structure containing “U”-shaped units coordinated to, andbridging between, MoMo bonds is illustrated by 36.100 This structure places met-als as a necessary part of the backbone. Furthermore, the metals form the rungs of aladder along the backbone strip.

Complex Structures 17

Rh Rh

O O

O O

OO

O O

C7H15 C7H15

C7H 15

34

C7H15

N

Fe

N

n

N N

O

MoMo

O

O O

R

OO

R

MoMo

O O

R

O O

R

O

N NO

n

N

N

N

N

O

35 36

C15H31

C15H31O

Znn

Various multibridged structures are not uncommon. Braided structures havebeen synthesized as the product of the phenyltetrazolate anion with metal cations. TheNi(II) and Fe(II) products, 37, give extremely viscous, aqueous solutions from whichflexible sheets and threads have been made.101 The ferromagnetic properties of theFe(II) products with long alkyl-chain-substituted tetrazolate anions varied with tem-perature because these chains align. As temperature changes, phase transitions

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M

N

N

N

N

N

N

N

N

N

M

N

N

N

N

N

N

M

N

N

N

N

N

N

M

N

N

N

N N = N

N N

N

C6H5

-

M = Ni, Fe

or long-chain alkyl

37

N N

NN

NN

O

N N

O N

N

N

Ru2+

N

N

N

Ru2+N N

N N

O

N

N

N

Ru2+

Ru2+

N

NN

ON

N

N

Ru2+

N

N

N

O

N

N

N Ru2+

N N

NO

N

N

N

Ru2+N

N

38

N

observable by differential scanning colorimetry (DSC) occur.102 These, in turn, varythe magnetic properties.

Star-like polymers, such as 38, have been formed through the coordination ofRu(II) with both bidentate and tridentate ligands.103 Examining the beauty of these

c01.qxd 6/2/2005 1:07 PM

structures is inspiring. For example, structure 38 is reminiscent of an artistic tilepattern.

One special grouping is the so-called parquet polymers. These polymers con-tain a flat, net-like organic “caging” that surrounds the metal ion. Two importantgroup members are poly(porphyrinato) and poly(phthalocyanato) complexes. Manyof the biologically important coordination polymers are members of this group,including hemoglobin, which utilizes a poly(porphyrinato) type of unit as the cage.Similar synthetic polymers have been made.104,105 For example, hematoporphyrin IXwas initially reacted with group 4 (IVB) metallocene dihalides forming complexcross-linked structures. These materials were then subjected to solutions containingcopper ions forming complexes such as 39.

Schiff Base Polymers 19

Zr

NH N

NHN

CH3

O R

CH3

CH3

O

OR

CH3

CH3

O

CH3

O

O

R

39

Zr

R

Cu

V. SCHIFF BASE POLYMERS

Schiff bases (imines) are formed from the reaction of aromatic amines withaldehydes or ketones. Schiff bases became important in dye-making efforts. Anumber of Schiff bases (such as 40) have been used to make coordination poly-mers. In 1961, Goodwin and Bailor used Schiff bases in the preparation of coor-dination polymers, 41, containing Cu, Ni, and Co.106 These materials were onlypoorly soluble.

Archer and co-workers overcame many of the early barriers and obtainedcharacterizable coordination polymers.36,37,107–109 Unlike the strategy used byGoodwin and Bailor that involved the coordination of metal ions to preexistingpolymers, Archer and co-workers reacted organic Schiff base ligands that couldcomplex with two metal ions producing coordination polymers. Archer and

c01.qxd 6/2/2005 1:07 PM


ON

N O

O N

NO

ZrCH2

n42

co-workers prepared and studied the luminescent properties of lanthanide-coordi-nated Schiff coordination polymers 12 and 13 mentioned earlier in this chapter.36,37

Included in their studies was the influence of different spacer groups and counteri-ons on polymer solubility. Through the use of end-group analysis using nuclearmagnetic resonance (NMR), molecular weights of 21,600 (M Y) and 18,500(M Eu) were found. Analogous coordination polymers were formed with lan-thanum, gadolinium, ytterbium, and cerium ions coordinated to bis(tetradentate)Schiff base ligands. Zirconium-coordinated Schiff base polymers, such as 42, were found to adhere to glass and metal surfaces.107–109 The preparation of a specific adhesive binder 43 using a zirconium coordination polymer and a methyl-substituted butyrolactone is shown below. The adhesion was so tenacious that ultra-sonic cleaning failed.

X

N

O

NM

n

n

O X

X

N

OH

N

H

40

41

X = SO2, CH2

M = Cu, Ni, Co

M2+

O X

c01.qxd 6/2/2005 1:07 PM

End-group capping is necessary before characterization is possible in dehy-drating solvents, because adhesion to glass, metal, or metal oxide surfaces is sostrong.

VI. PORPHYRIN SYSTEMS

Conjugated polymers containing metal porphyrins within their structures havepotential use in solar energy conversion, optical and electronic devices, and asenzyme mimics. A brief glimpse of some porphyrin-containing coordination poly-mers is provided below.

High molecular weight metalloporphyrin-containing products have been difficult to characterize because of their general poor solubility.110–113

Pomogailo et al.111 incorporated metalloporphyrins into the side chain of poly-mers producing high molecular weight products via addition polymerization ofporphyryl-coordinated metal monomers. For example, the copper and zinc monomercomplexes 44 and 45 were copolymerized with styrene producing high molecularweight products. This is an example of the approach for coordination polymer syn-thesis given on page 15.

Metalloporphyrin units, when properly aligned, induce nonlinear opticalproperties. Anderson and co-workers reported that the microscopic polarizabili-ties of porphyrins in polymers were three orders of magnitude greater than those of monomeric porphyrins.112 This report described the largest one-photon,

Porphyrin Systems 21

43

OHC

N

HCN O

OCH2

N

CHNO

Zr

NNH

O

HC

N

HCN O

O

CH2

O

CH

OOZr

C)n

C)nCH2CH

CH2CHOH (

OCH3

O H (

CH3 O

H

OHC

N

HCN O

OCH2

N

CHNO

Zr

H2NNH2

O

HC

N

HCN O

O

CH2

O

CH

OOZr

n −1

n −1

OO

CH3

+

+ 2 HCl

c01.qxd 6/2/2005 1:07 PM


N N

NNZn

N

O

N

O

N

O

N

O

46

n

47

N N

NN

Zn

N

O

N

O

N

O

N

O

CuCl

TMEDA

Where TMEDA = N, N, N ′, N ′ - tetramethylethylenediamine

off-resonance, third-order optical susceptibility for an organic substance. Theresults are indicative of interporphyrin conjugation. The products, such as 47, weresynthesized with bulky groups in the meso positions of the porphyrin, allowing the polymer to be soluble in the presence of a metal-coordinating ligand such aspyridine.113

N N

N N

44 45

M

N N

N N

M

Metalloporphyrin coordination polymers have been used to sense dissolvedoxygen by taking advantage of their luminescent properties,114 suggesting that theuse of coordination polymers in sensors may be a growing application area.

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VII. PHTHALOCYANINE SYSTEMS

Phthalocyanines are structurally similar to porphyrins except there are fouradditional arenes and an additional four nitrogen atoms in the inner grouping. Marveland Rassweiler94 reported the synthesis of copper-coordinated phthalocyanine poly-mers in 1958. The polymerization was achieved through the reaction of pyromelliticacid, phthalic anhydride, and urea to give products very similar to those reported 1 year later by Drinkard and Bailor95 (see 30 and 31) except the carboxyl functionswere not present. The products were blue-green to green-black in color. Kimura et al.115 reported the synthesis of linear and network copper and zinc polyphthalo-cyanines via olefin metathesis polymerization of the corresponding monomers. Thesynthesis of the copper phthalocyanine monomer, 50, and the formation of linearpolymer 51 by metathesis polymerization is shown below.

Phthalocyanine Systems 23

N

N

N

N

N

N

N

N

Cu

OO

O

ONC

NC

C

49

50

51

48

uCl2

N

N

N

N

N

N

N

N

Cu

OO

(PCy3)2Cl2Ru(=CHC6H5)

n

CN

CN

c01.qxd 6/2/2005 1:07 PM

Cofacial phthalocyanine polymers have been featured in some studies inattempts to produce electrically conducting products. In these systems, the macro-cyclic rings are stacked forming a “shish kebab”-like structure with the metalbeing part of the polymer backbone. Electrical, thermal, and chemical propertiesare generally studied as a function of the number of atoms separating the phthalo-cyanine rings and nature of substituents that are present on the rings. These sub-stituents are often present to allow chain alignment and to discourage closeinteraction between separate polymer chains, encouraging solubility. The synthe-sis of polymer 54 occurs by reaction of the ferrous phthalocyanine complex 52,with pyrazine, 53.97


NN

N

N

N

N

N

NFe

n

NN

N

N

N

52

53

54

N

N

NFe + N N N N

VIII. PYRIDINE AND RELATED SYSTEMS

Reactions involving pyridines and metal ions have been widely reported andare part of most inorganic courses. Extensions producing polymeric products arestraightforward simply requiring: (1) the presence of several pyridines on a sin-gle ligand; (2) polymerization of pyridine-containing monomers that already contain the complexed metal ion; or (3) the presence of one or more pyridineunits on an already existing polymer. An example of polymer formed from thereaction of metal ions with ligands containing several pyridine units is given inthe top half of the scheme below, where monomer 55 is reacted with rutheniumchloride giving polymer 56. This product was also made116 using the palladium-catalyzed Suzuki coupling reaction between monomers 57 and 58, again formingpolymer 56. This pathway represents approach 2 for the synthesis of pyridinecoordination polymers.

A variation of this second approach is the polymerization of vinyl monomerswith at least one of them containing metal ions bonded previously. The next schemeillustrates this approach. Here, a ruthenium-containing monomer, 61, is reacted withtwo other dye-containing monomers, 59 and 60. These products were more soluble

c01.qxd 6/2/2005 1:07 PM

than polymers prepared by the grafting approach. The adsorption and luminescentproperties of polymer 62 was greater than that of dyes 59 and 60 and the rutheniumcomplexes 61.117

The third approach is illustrated by the formation of polymer 67 through reac-tion with a terpyridine-containing polymer, 63.118 In this example, block copolymers

Pyridine and Related Systems 25

C6H13

C6H13

(HO)2B B(OH)2

[Pd(diphenylphosphinoferrocene)Cl2]

N

N

N

N

N

N

C6H13

C6H

55

56

57 58

13

N

N

N

N

N

N

C6H13

C6H13

RuCl3 3H2O,

AgBFF4/acetone

Ru2+

N

N

N

N

N

N

BrRu2+Br +

n2 BF4

−

2 BF4−

1-butanol/Dimethylacetamide

DMA, Et3N

DIRECT COORDINATION

SUZUKI COUPLING

c01.qxd 6/2/2005 1:07 PM

+

59 60

62

61

NN

N

NN

NRu2++

N

O

O

NN

N

NN

N

OO

O

O

N

Ru2+

0.29 0.3 0.41

N

O

O

OO

O

O

N

N N

63

64

65

66

67

N

OO

OO

n RuCl3, MeOH

NN

N

O O O On

Ru

ClClCl

N

N

N

Om

N

N

N

Om

N

N

N

OO

OO

nRu2+

c01.qxd 6/2/2005 1:07 PM

were made by joining the polyethylene oxide and polystyrene blocks by generatinga bis(terpyridine) ruthenium complex at the juncture of the blocks.

IX. MISCELLANEOUS RING AND MULTISITE SYSTEMS

A number of ring and multisite ligand systems have been employed to chelatemetal ions. These include crown ethers, poly(ethylene oxides) and poly(methyleneoxides), catenanes, rotaxanes, and calixarenes. Some have been studied with the intentof producing products that exhibit electro- and photoactivity.

The following scheme illustrates Swager’s119,120 use of both a cyclic system,68, and linear multisite molecule, 69, to form the coordination precursor 70 topolymer 71. Swager and co-workers120 synthesized conducting polymetallorotax-anes that are coordinated to zinc and copper ions. Thus, reaction of bithionyl-substituted bpy, 69, with the macrocyclic 1,10-phenanthroline(phen), 68, gave

Miscellaneous Ring and Multisite Systems 27

N

N

O

O

68

69

70

71

O

O

O

O

N NS S

S S

N N

O O

O OO O

N NS S

S SM

N N

O O

O OO O

N NS SS S

M

+

n

Zn(ClO4)2orCu(CH3CN)4BF4

− 2e, −2H+

c01.qxd 6/2/2005 1:07 PM

a metallorotaxane, 70, which were electropolymerized to give the polymetalloro-taxane, 71.

X. COORDINATION NETWORKS CONSTRUCTEDFROM ORGANOMETALLIC LIGAND SPACERS

Coordination-directed self-assembly, using organometallic species to con-struct coordination networks with infinite macrostructures can be considered asanother classification of coordination polymers. In earlier sections of this chapter(pp. 6, 8, 9, and 15), many examples were presented of organic spacer ligands containing two chelating functions, which formed coordination polymers whenreacted with metal ions. We will now discuss briefly cases where the spacer has anorganometallic unit pendent to the spacer (or as a part of the spacer chain), which isthen reacted with another, M, through coordination complexing, to form polymers.


SPACER + M SPACERM

n

+ M SPACERM

n

SPACER

where is an organometallic moiety

Many supramolecular structures have been made with specifically defined geometries that contain organometallic units.121–124 Geometry control has employedmetal complexes as sides or corners to generate a variety of 2D and 3D shapes such astriangles, squares, hexagons, cubes, parallopipides, and so on. The formation of molec-ular triangle 72 is an example of where the square-planar geometry about a Pt, the 180angles of the linear rod, and the bent (60) phenanthrene create a situation where thetriangle structure self-assembles.126 Here, pyridine nitrogen coordinates to Pt, replac-ing nitrate, and the linear organometallic Pt complexes become the sides of the trian-gle. Compound 72, while a supramolecular species, it is not a polymer. However, thissame sort of self-assembly has been used to produce solid-phase macromolecules.

The reaction of copper(II) acetate with hydroquinone gave the novel dicop-per (I) diacetate moiety held by η2,η2-bonding to benzequinone [e.g., Cu2(µ2-η2,η2-benzoquinone)(OAc)2] via an oxidation–reduction reaction.125 When bpy

c01.qxd 6/2/2005 1:07 PM

Coordination Networks Constructed from Organometallic Ligand Spacers 29

Pt

Pt

ONO2PEt3

PEt3

ONO2

PEt3

PEt3

Pt PEt3Et3P

N

N

+

PtPtPEt3

Et3P N

Et3P

PEt3N

Pt PtPEt3

Et3P

Et3P

PEt3

N NPt Pt

PEt3

Et3P

Et3P

PEt3

Pt Pt

PEt3

PEt3

N

PEt3

PEt3

NPt

PEt3

P

72

Et3

was added, the one-dimensional (1D) coordination polymer, 73, is formed as bpyunits that act as main chain coordination units and the backbone contains Cu–Cubonds.

Coordination polymers containing diisonitriles and diphosphines, that serve asspacers while connecting metal ions, were reported by Harvey.126,127 Structure 74 is anexample. Supramolecular polymeric arrays containing bimetallic nodes, such as 76,have been synthesized128–131 from the bis-dinuclear rhodium species 75 by Cottonet al.128,130–131 and Chisholm.129

c01.qxd 6/2/2005 1:07 PM

An interesting new type of coordination network was reported by Sweigartand co-workers in 2001132 containing organometalloligand spacers, with a pendentMn(CO)3 moiety on quinoid systems along the main propagation chain.

Electrophilic activation by the Mn(CO)3 moiety in 77 promotes deprotonation,giving the η5-semiquinone complex, 78, which actually exists in a linear polymer


74

P P

M+

C C

NN

RR

P P

M+

C C

NN

RR

nM + = Cu+ , A g+

73

N NCuN N Cu

OO O

O

OO

n

Rh

Rh

Rh

Rh

Rh

Rh

Rh

Rh

Rh

Rh N

O

O O

O

Rh

RhN

O

OO

O CH2

CH2 NN

NN

NN

NN

NN

NC

N

OMeM

75

76

eOH

c01.qxd 6/2/2005 1:07 PM

structure 79 held together by hydrogen-bonding. The o-quinone Mo(CO)3 complexreacts easily with divalent metal ions through coordination to both oxygens. Thisgives neutral cheated monomers, M(o-quinone manganese tricarbonyl)2 L2, whereM Mn, Cd, or Co. If the ligand L is 4.4-bpy, 1D polymers form as represented bystructure 80.


+Mn(CO)3

HO OH++

− H+

HO OH

M

77 78

n(CO)3+

79

80

OH

O

HO

O

HO

Mn(CO)3

Mn(CO)3Mn(CO)3

2.47 A

Mn(CO)3 M

M = Mn, Cd, or Co

n(CO)3 Mn(CO)3

NMN

OO

NMN

OO

NMN

OO

OO OO OO

Mn(CO)3Mn(CO)3 Mn(CO)3

The p-quinone Mn(CO)3 monomer can form oxygen-to-metal bonds arrangedin coordination networks.133 Thus, crystalline polymers, 81, formed as 1D strings inmoderate to excellent yields with Mn, Ni, Co, and Cd cations. A diverse array of 1D,2D, and 3D polymers were obtained with speciWc architectures that depended on thegeometrical requirements of the added metal ion, the solvent, and on the presence ofadded organic ligands that function as additional spacers. For example, the use of4,4-bpy as the axial ligand produced the 2D network 82.133

c01.qxd 6/2/2005 1:07 PM


81

82

Mn(CO)3

Mn(CO)3 M

M = Mn, Ni, Co, Cd

n(CO)3

Mn(CO)3 Mn(CO)3

Mn(CO)3

O

O

M

O

O

L

L

O

O

O

O

O

O

M

O

O

L

L

Mn(CO)3

Mn(CO)3 Mn(CO)3

Mn(CO)3 Mn(CO)3

Mn(CO)3

Mn(CO)3

Mn(CO)3 Mn(CO)3

Mn(CO)3 Mn(CO)3

Mn(CO)3

O

O

M

O

OO

O

O

O

O

O

M

O

O

O

O

M

O

OO

O

O

O

O

O

M

O

ON

N

N

N

Using a bridging metal, such as Zn(II), that prefers tetrahedral coordinationgeometry, resulted in a 3D polymer where the solid-state structure consists of twointerpenetrating diamonded networks.132

Lanthanides can be ligated by organometallic moieties to produce solid poly-meric networks.134 When Fe3(CO)12 was reduced by ytterbium in liquid ammonia,followed by treatment with MeCN, two types of coordination networks wereformed containing the organometalloligand [Fe(CO)4]2.134 Both the ladder poly-mer structure, 83, and the extended sheet geometry, 84, were formed. These struc-tures contain both heterometallic Yb–Fe bonds and carbonyl linkages, where the[Fe(CO)4]2 moiety serves as an organometallic ligand that coordinates ytterbiumnodes via carbonyl linkages. Methyl cyanide (MeCN) ligands on the Yb atoms arenot shown.

A growing area, which will become increasingly important for coordinationpolymers, is the development of stimuli-responsive polymers. This class of materi-als shows dramatic property changes in response to a stimulus. Stimuli-responsivepolymers can be classified based on their response to photo, electrical, chemical,

c01.qxd 6/2/2005 1:07 PM

and mechanical stimuli.135 Beck and Rowan136 reported the use of reversible metal–ligand coordination interactions to assemble metallo-supramolecular gel-like sys-tems that can respond to thermal, mechanical, and photochemical simulations. Thetridentate ligand, bis(2,6-bis(1-methylbenzimidazdyl)-4-hydroxypyridine), 85, wasemployed as the metal chelating function. This ligand can form 2:1 ligand–metalcomplexes with transition metals and 3:1 complexes with lanthanide ions. Mixing atransition metal ion (Co2 or Zn2) with a lanthanide ion (La3 or Eu3) in 95%transition metal/5% lanthanide ratios produced cross-linked gels when the bis ana-logues of 85, for example, 86, was used.136 These gels are represented schematicallyby structure 87a–d. All four of these gels were thermoresponsive, changing colorwith changes in temperature. This response is due to lanthanide–ligand bond break-ing as the temperature is raised. The gels are also mechanoresponsive, exhibitingshear-thinning behavior. Furthermore the Zn/Eu polymers were also photolumines-cent and this property was used to probe the bonding structure within the gels.Heating provoked a reduction in the Eu3 chelate emission, but no change in the lig-and emission. This confirmed the Eu3-to-ligand bonds were thermally broken andnot the Zn2-to-ligand linkages.

The field of coordination polymers is rich in both its diversity of structureand variety of applications. Interesting work continues to appear regularly. As a finalexample, we mention the tris(bipyridyl) Ru(II) macromolecular architecture ofLeBouder et al., which features octupolar complexes that undergo supramolecularself-ordering into dendritic structures.137 Their nonlinear optical properties appearpromising. Indeed, this entire field evokes promise! Some of that promise is illus-trated in the chapters that follow.


YbFe

C O

O C

Yb F

83 84

e

O C

C O

Fe Yb

C O

O C

Yb Fe

OC

OC

CO

CO

OC

OC

CO

CO

YbFe

C O

O C

Yb Fe

O C

C O

Fe Yb

C O

O C

Yb Fe

O C

C O

YbFe

C O

O C

Yb Fe

O C

C O

Fe Yb

C O

O C

Yb Fe

O C

C O

C

O

O

C

O

C

C

O

c01.qxd 6/2/2005 1:07 PM


OOOON

NN

NN

Me

Me

O O N

NN

NN

Me

Me

N

NN

NN

85

86

86

Me

Me

M M M

M

n

n

M

1. 3% La(NO3) or Eu(NO3)

3

3

2. 97% Co(ClO4) o

87a La3+ / Co2+

87b La3+ / Zn2+

87c Eu3+ / Co2+

87d Eu3+ / Zn2+

r Zn(ClO4)2

2

XI. REFERENCES

1. H. Preut, F. Huber, Z. Anorg. Allg. Chem. 435, 234 (1977).

2. F. A. Cotton, G. Wilkerson, Advanced Inorganic Chemistry, John Wiley & Sons, Inc., New York, 1999.

3. F. Basolo, R. C. Johnson, Coordination Chemistry, Science Reviews, London, 1994.

4. M. J. Winter, d-Block Chemistry, Oxford Chemistry Primers, Oxford Science Pubs., Oxford,1994.

5. M. Winter, Fundamentals of Inorganic Chemistry, Oxford University Press, Cary, NC, 2001.

6. R. van Eldik, Advances in Inorganic Chemistry, Elsevier, New York, 2004.

7. G. Messler, Inorganic Chemistry, Prentice Hall, Englewood CliV, NJ, 2003.

8. S. Asperger, Chemical Kinetics and Inorganic Reaction Mechanisms, Kluwer, New York, 2003.

9. J. Huheey, Inorganic Chemistry, Addison-Wesley, New York, 2003.

10. J. C. Bailor, in Preparative Inorganic Reactions, Vol. 1, W. Jolly, Ed., Interscience, New York,1964.

11. R. Archer, Inorganic and Organometallic Polymers, John Wiley & Sons, Inc., New York, 2001.

12. C. Carraher, H. Blaxall, J. Schroeder, W. Venable, Org. Coat. Plast. Chem. 39, 549 (1979).

13. C. Carraher, H. Blaxall, Angew. Makromol. Chem. 83, 37 (1979).

14. C. Carraher, L. Hedlund, Polymer P. 16(2), 264 (1975).

15. C. Carraher, L. Torre, Org. Coat. Plast. Chem. 45, 252 (1981).

16. C. Carraher, L. Torre, in Macromolecular Solutions: Solvent-Property Relationships inPolymers, R. Seymour, G. A. Stahl, Eds., Pergamon, New York, 1982.

17. C. Carraher, L. Reckleben, in Polymer ModiWcation, G. Swift, C. Carraher, C. Bowman,Eds., Plenum, New York, 1997.

c01.qxd 6/2/2005 1:07 PM

18. A. Zhao, C. Carraher, PMSE, 89, 367 (2003).

19. J. C. Bailor, in Organometallic Polymers, C. Carraher, J. Sheats, C. Pittman, Eds.,Organometallic Polymers, Academic Press, New York, 1978.

20. A. Abd-El-Aziz, C. Carraher, C. Pittman, J. Sheats, M. Zeldin, Macromolecules ContainingMetal and Metal-Like Elements, Vol. 1, A Half Century of Metal- and Metalloid-ContainingPolymers, John Wiley & Sons, Inc., Hoboken, NJ, 2003.

21. B. M. Foxman, S. W. Gersten, Encyclopedia of Polymer Science and Engineering, 2nd ed.,John Wiley & Sons, Inc., New York, 1988.

22. K. Jensen, Z. Anorg. Chem. 252, 227 (1944).

23. C. Carraher, J. Schroeder, Polym. Lett. 13, 215 (1975).

24. C. Carraher, J. Schroeder, Polym. P. 19(2), 619 (1978).

25. C. Carraher, J. Schroeder, Polym. P. 16, 659 (1975).

26. R. Knapp, A. Schott, M. Rehahn, Macromolecules 29, 478 (1996).

27. C. Carraher, G. Hess, W. Chen, J. Polym. Mater. 8, 7 (1991).

28. C. Carraher, T. Manek, D. Giron, M. Trombley, K. Casberg, W. J. Scott, in New Monomers andPolymers, B. Culbertson, C. Pittman, Eds., Plenum, New York, 1983.

29. C. Carraher, W. Chem, G. Hess, I. Lopez-Esbenshade, PMSE 78, 104 (1998).

30. C. Carraher, W. Chem, G. Hess, D. Giron, PMSE 59, 530 (1988).

31. C. Carraher, G. Hess, W. Chem, PMSE 59, 744 (1988) and 58, 557 (1988).

32. C. Carraher, W. Chem, G. Hess, D. Giron, in Progress in Biomedical Polymers, C. Gebelein, R. Dunn, Eds., Plenum, New York, 1990.

33. C. Carraher, V. Nwufoh, J. R. Taylor, PMSE 60, 685 (1989).

34. C. Carraher, A. Gasper, M. Trombley, F. Deroos, D. Giron, G. Hess, K. Casberg, in NewMonomers and Polymers, B. Culbertson, C. Pittman, Eds., Plenum, New York, Chapt. 9, 1983.

35. P. B. Block, Inorg. Macromol. Rev. 1(2), 115 (1970).

36. H. Chen, R., D. Archer, Macromolecules 28, 1609 (1995).

37. H. Chen, R., D. Archer, Macromolecules 29, 1957 (1996).

38. M. Rehahn, Acta Polym. 49, 201 (1998).

39. C. Carraher, S. Tsuzo, W. Feld, J. Dinunzio, Org. Coat. Appl. Polyms. Sci. 46, 254 (1982).

40. C. Carraher, S. Tsuzo, W. Feld, J. Dinunzio, in ModiWcation of Polymers, C. Carraher, J. Moore, Eds., Plenum, New York, Chapts. 15 and 16, 1983.

41. L. G. Donaruma, S. Kitoch, G. Walsworth, J. Depinto, J. Edzwald, Macromolecules 12, 435(1979).

42. E. Tomic, T. Campbell, V. Foldi, J. Polym. Sci. 62, 379, 387 (1962).

43. C. Carraher, C. Ademu-John, J. Fortman, D. Giron, C. Turner, R. Linville, in PolymericMaterials in Medication, C. Gebelein, C. Carraher, Eds., Plenum, New York, 1985.

44. C. Carraher, C. Ademu-John, J. Fortman, D. Giron, C. Turner, PMSE 51, 307 (1984).

45. C. Carraher, X. Xu, Polymer Material Science and Engineering (PMSE) 75, 182 (1996).

46. C. U. Pittman, Jr., G. O. Evans, Chemtech 560, (1973).

47. C. U. Pittman, Jr., Q. Ng, A. Hirao, R. Hanes, a chapter in Colloques InterNationaux du D. N.R. S. No. 281, Relations Between Homogeneous and Heterogeneous Catalysts, (a book),Lyon, France, Nov. 3–6 (1977), 49–100 (1979).

48. C. U. Pittman, Jr., a chapter in Polymer-supported Reagents, Catalysts and Protecting Groups,(a book), P. Hodge, D. C. Sherrington, Eds., John Wiley & Sons, Inc. pp. 249–291, 1980.

49. C. U. Pittman, Jr., chapter 55, in Comprehensive Organometallic Chemistry, 5, “The Synthesis,Reactions, and Structure of Organometallic Compounds,” G. Wilkinson, F. G. A. Stone, Eds.,Pergamon Press, New York, 1982.

50. C. U. Pittman, Jr., Polymer News 4, 5–15 (1977).

References 35

c01.qxd 6/2/2005 1:07 PM

51. G. O. Evans, C. U. Pittman, Jr., R. McMillan, R. T. Beach, R. Jones, J. Organometal. Chem.67, 295 (1974).

52. C. U. Pittman, Jr., R. M. Hanes, Ann. N.Y. Acad. Sci. 239, 76 (1974).

53. S. E. Jacobson, C. U. Pittman, Jr., J. Chem. Soc. Chem. Comm. 187 (1975).

54. C. U. Pittman, Jr., L. R. Smith, R. M. Hanes, J. Am. Chem. Soc. 97, 1742 (1975).

55. C. U. Pittman, Jr., L. R. Smith, J. Am. Chem. Soc. 97, 1749 (1975).

56. C. U. Pittman, Jr., B. T. Kim, W. M. Douglas, J. Org. Chem. 40, 590 (1975).

57. F. R. Hartley, Supported Metal Complexes, D. Reidel Publishing Co., Dordrecht, The Netherlands,1985. Also see A. K. Kakkar, Chem. Rev. 102 (2002); I. F. J. Vankelecom, P. A. Jacobs, in ChiralCatalyst Immobilization and Recycling, D. E. DeVos, I. F. J. Vankelecom, P. A. Jacobs, Eds.,Wiley-VCH, Weinheim, 19–42, 2000.

58. C. U. Pittman, Jr., L. R. Smith, J. Am. Chem. Soc. 97, 341 (1975).

59. C. U. Pittman, Jr., L. R. Smith, in Organotransition Metal Chemistry, a book, Y. Ishii, M. Tsutsui, Eds., Plenum Press, New York, p. 143, 1975.

60. C. U. Pittman, Jr., L. R. Smith, S. E. Jacobson, in Catalysis. Heterogeneous andHomogeneous, B. Delmon, G. Jannes, Eds., Elsevier Publ. Co., Amsterdam, The Netherlands,pp. 393–406, 1975.

61. H. Hiramoto, C. U. Pittman, Jr., J. Mol. Catal. 1, 73 (1975).

62. C. U. Pittman, Jr., S. E. Jacobson, H. Hiramoto, J. Am. Chem. Soc. 97, 4774 (1975).

63. C. U. Pittman, Jr., S. E. Jacobson, J. Mol. Catal. 293 (1977/78).

64. C. U. Pittman, Jr., S. K. Wu, S. E. Jacobson, J. Catalysis 44, 87 (1976).

65. C. U. Pittman, Jr., S. Jacobson, L. R. Smith, W. Clements, H. Hiramoto, in Catalysis inOrganic Synthesis, P. Rylander, ed., Academic Press, New York, pp. 393–405, 1976.

66. C. U. Pittman, Jr., R. M. Hanes, J. Am. Chem. Soc. 98, 5402 (1976).

67. C. U. Pittman, Jr., A. Hirao, J. J. Yang, Q. Ng, R. Hanes, C. C. Lin, Preprints Div. PetroleumChem. ACS 22, 1196–1200 (1977).

68. C. U. Pittman, Jr., R. M. Hanes, J. Org. Chem. 44, 1194 (1977).

69. C. U. Pittman, Jr., Q. Ng, J. Organometal. Chem. 153, 85–97 (1978).

70. C. U. Pittman, Jr., A. Hirao, J. Org. Chem. 43, 640–646 (1978).

71. C. U. Pittman, Jr., C. C. Lin, J. Org. Chem. 43, 4928–4932 (1978).

72. C. U. Pittman, Jr., G. Wilemon, Ann. N.Y. Acad. Sci. 333, 67–73 (1980).

73. N. E. Leadbeater, M. Marco, Chem. Rev. 102, 3217–3274 (2002).

74. C. A. McNamara, M. J. Dixon, M. Bradley, Chem. Rev. 102, 3275–3300; D. E. Bergbreiter,Chem. Rev. 102, 3345–3384 (2002).

75. P. Mastrorilli, C. F. Nobile, Coord. Chem. Rev. 248, 377 (2004).

76. R. D. Sanner, R. G. Austin, M. S. Wrighton, W. D. Honnick, C. U. Pittman, Jr., J. Inorg. Chem.18(4), 928–932 (1979).

77. C. U. Pittman, Jr., W. D. Honnick, J. J. Yang, J. Org. Chem. 45, 684–689 (1980).

76. C. U. Pittman, Jr., Y. F. Liang, J. Org. Chem. 45, 5048–5052 (1980).

77. C. U. Pittman, Jr., Q. Y. Ng, U.S. Patent, 4,258,206, March 24 (1981).

78. C. U. Pittman, Jr., G. M. Wilemon, Q. Y. Ng, L. I. Flowers, Polym. Preprints 21(1), 153–154(1981).

79. C. U. Pittman, Jr., U.S. Patent 4,243,829, January 6 (1981).

80. C. U. Pittman, Jr., E. H. Lewis, M. Habib, J. Macromol. Sci. Chem. 15(5), 897–914 (1981).

81. C. U. Pittman, Jr., Y. Kawabata, R. Kobayashi, J. Mol. Catal. 12, 113 (1981).

82. C. U. Pittman, Jr., G. M. Wilemon, J. Org. Chem. 46, 1901 (1981).

83. C. U. Pittman, Jr., R. M. Hanes, J. J. Yang, J. Mol. Catal. 15, 77–381 (1982).

84. C. U. Pittman, Jr., Y. Kawabata, L. I. Flowers, J.C.S. Chem. Commmun. 473–474 (1982).


c01.qxd 6/2/2005 1:07 PM

References 37

85. C. U. Pittman, Jr., L. I. Flowers, Q. Ng, Preprints Div. Petroleum Chem. 27(3), 614–623 (1982).

86. C. U. Pittman, Jr., Chen De-An, J. Mol. Catal. 21, 405–414 (1983).

87. S. C. Yu, S. Hou, W. K. Chan, Macromolecules 33, 3259 (2000).

88. F. Higashi, C. S. Cho, H. Kakinoki, O. Sumita, J. Polym. Sci. Chem. Ed. 17, 313 (1979).

89. C. Carraher, C. Ademu-John, J. Fortman, D. Giron, R. Linville, PMSE 49, 210 (1983).

90. C. Carraher, C. Ademu-John, J. Fortman, D. Giron, C. Turner, J. Polym. Mat. 1, 116 (1984).

91. C. Carraher, C. Ademu-John, J. Fortman, D. Giron, in Metal-Containing Polymeric Systems,J. Sheats, C. Carraher, C. Pittman, Eds., Plenum, New York, 1985.

92. C. Carraher, Y. Jiang, D. Baird, PMSE 89, 517 (2003).

93. C. Carraher, Y. Jiang, D. Baird, PMSE 89, 543 (2003).

94. C. S. Marvel, J. H. Rassweiler, J. Am. Chem. Soc. 80, 1197 (1958); 39, 513 (1967).

95. W. C. Drinkard, J. C. Bailor, J. Am. Chem. Soc. 81, 4795 (1959).

96. J. T. Wrobleski, D. B. Brown, Inorg, Chem. 18, 498 and 2738 (1979).

97. B. Diel, T. Inabe, N. Jaggi, J. Lyding, O. Schneider, M. Hameck, C. Kannewurf, T. Marks, L. Schwarz, J. Am. Chem. Soc. 106, 3207 (1984).

98. W. Xue, F. Kuhn, E. Herdtweck, Q. Li, Eur. J. Inorg. Chem. 213 (2001).

99. B. Jiang, S. Yang, D. Barbini, W. E. Jones, Chem. Commun. 213 (1998).

100. M. H. Chisholm, Acc. Chem. Res. 33, 53 (2000).

101. L. Richards, I. KouWs, C. Chan, J. Richards, C. Cotter, Inorg. Chem. 105, 121 (1985).

102. T. Fujigaya, D.-L. Jiang, T. Aida, J. Am. Chem. Soc. 125, 14690 (2003).

103. E. C. Constable, Chem. Commun. 1073 (1997).

104. C. Carraher, J. Haky, A. Rivalta, D. Sterling, PMSE 70, 329 (1993).

105. C. Carraher, J. Haky, A. Rivalta, in Functional Condensation Polymers, C. Carraher, G. Swift,Eds., Kluwer, New York, 2002.

106. H. Goodwin, J. C. Bailor, J. Am. Chem. Soc. 83, 2467 (1961).

107. H. Chem, J. A. Corin, R. D. Archer, Inorg. Chem. 34, 2306 (1995).

108. B. Wang, R. D. Archer, Chem. Mater. 5, 317 (1993).

109. R. D. Archer, B. Wang, Polym. Mater. Sci. Eng. 61, 101 (1989) and references cited therein.

110. H. L. Anderson, Chem. Commun. 2323 (1999).

111. A. D. Pomogailo, N. Bravaya, V. Razumov, I. Voloshanovskii, N. Kitenko, V. Berezovskii, A. Kuzaev, A. Ivanchenko, Russ. Chem. Bull. 45, 2773 (1996).

112. T. Screen, K. Lawton, G. S. Wilson, N. Dolney, R. Ispansoiu, T. Goodson, S. Martin, D. Bradley, H. Anderson, J. Mater. Chem. 11, 312 (2001).

113. S. M. Kuebler, R. Denning, H. Anderson, J. Am. Chem. Soc. 122, 339 (2000).

114. A. S. Holmes-Smith, A. Hamill, M. Campbell, M. Uttamlal, Analyst 24, 1463 (1999).

115. M. Kimura, K. Wada, K. Ohta, K. Hanabusa, H. Shirai, N. Kobayashi, Macromolecules 34,4706 (2001).

116. S. Kelch, M. Rehahn, Macromolecules 32, 5818 (1999).

117. J. Serin, X. Schultz, A. Andronov, J. M. J. Frechet, Macromolecules 35, 5396 (2002).

118. J. Gohy, G. Lohmeijer, U. S. Schubert, Macromolecules 35, 4560 (2002).

119. S. S. Zhu, P. Carroll, T. M. Swager, J. Am. Chem. Soc. 118, 8713 (1996).

120. S. S. Zhu, T. M. Swager, J. Am. Chem. Soc. 119, 12568 (1997).

121. S. Leininger, B. Olenyuk, P. J. Stang, Chem. Rev. 100, 853–908 (2000) and T. Yamamoto, A. M. Arif, P. J. Stang, J. Am. Chem. Soc. 125, 12309–12317 (2003).

122. S. R. Seidel, P. J. Stang, Acc. Chem. Res. 35, 972–983 (2002).

123. A. H. Eisenberg, M. V. Ovchinnikov, C. A. Mirkin, J. Am. Chem. Soc. 125, 2836–2837 (2003).

c01.qxd 6/2/2005 1:07 PM

124. Y. K. Kryschenko, S. R. Seidel, A. M. Arif, P. J. Stang, J. Am. Chem. Soc. 125, 5193 (2003).

125. S. Masaoka, G. Akiyama, S. Horike, S. Kitagawa, T. Ida, K. Endo, J. Am. Chem. Soc. 125,1152 (2003).

126. P. D. Harvey, Coord. Chem. Rev. 219, 17 (2001).

127. P. D. Harvey, Macromol. Symp. 196, 173–185 (2003).

128. F. A. Cotton, C. Lin, C. A. Murillo, Acc. Chem. Res. 34, 759 (2001).

129. M. H. Chisholm, Acc. Chem. Res. 33, 53 (2000).

130. F. A. Cotton, J. P. Donahue, C. A. Murillo, J. Am. Chem. Soc. 125, 5436–5450 (2003).

131. F. A. Cotton, C. Lin, C. A. Murillo, Chem. Commun. 11 (2001).

132. M. Oh, G. B. Carpenter, D. A. Sweigart, Angew. Chem. Int. Ed., Engl. 40, 3191 (2001).

133. M. Oh, G. B. Carpenter, D. A. Sweigart, Angew. Chem. Int. Ed., Engl. 41, 3650 (2002).

134. C. E. Plecnik, S. Liu, S. G. Shore, Acc. Chem. Res. 36, 499 (2003) and references citedtherein.

135. T. P. Russell, Science 297, 964 (2002).

136. J. B. Beck, S. J. Rowan, J. Am. Chem. Soc. 125, 13922 (2003).

137. T. LeBouder, O. Maury, A. Bondon, K. Costuas, E. Amouyal, I. Ledoux, J. Zyss and H. LeBozec, J. Am. Chem. Soc. 125, 12,284 (2003).


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