carbyne and carbynoid strucfures978-94-011-4742-2/1.pdf · chapter 2: carbyne and carbynoid...

CARBYNE AND CARBYNOID STRUCfURES

Physics and Chemistry of Materials

with Low-Dimensional Structures

VOLUME 21

Editor-in-Chief

F. LEVY. Institut de Physique Appliquee, EPFL, Departement de Physique, PHB-Ecublens, CH-JOI5 Lausanne, Switzerland

Honorary Editor

E. MOOSER, EPFL, Lausanne, Switzerland

International Advisory Board

J. V. ACRIVOS, San Jose State University, San Jose, Calif., U.S.A.

R. GIRLANDA, Universita di Messina, Messina, Italy

H. KAMIMURA, Dept. of Physics, University of Tokyo, Japan

W. Y. LIANG, Cavendish Laboratory, Cambridge, U.K.

P. MONCEAU, CNRS, Grenoble, France

G. A. WIEGERS, University ofGroningen, The Netherlands

The titles published in this series are listed at the end of this volume.

Carbyne and Carbynoid Structures

Editedby

Robert B. Heimann Department of Mineralogy, Freiberg University of Mining and Technology, Freiberg, Germany

'Sergey E. Evsyukov A.N. Nesmeyanov Institute ofOrgano-Element Compounds, The Russian Academy of Sciences, Moscow, Russia

and

Ladislav Kavan J. Heyrovsky Institute of Physical Chemistry, Prague, Czech Republic

SPRINGER-SCIENCE+BUSINESS MEDIA, B.V.

A C.I.P. Catalogue record for this book is available from the Library of Congress.

ISBN 978-94-010-5993-0 ISBN 978-94-011-4742-2 (eBook) DOI 10.1007/978-94-011-4742-2

Printed on acid-free paper

AlI Rights Reserved ©1999 Springer Science+Business Media Dordrecht Originally published by Kluwer Academic Publishers in 1999 No part of the material protected by this copyright notice may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording or by any information storage and retrieval system, without written permission from the copyright owner

HEIMANN - EVSYUKOV - KAVAN

List of Contributors Preface

Chapter 1: Introduction

Table of Contents

1.1. The discovery of carbyne (YlI.P.KlIdryavtsev) 1.2. The nature of carbyne: pros and cons (R.B.Heimann)

Chapter 2: Carbyne and carbynoid structures in nature

2.1. Carbon-how many allotropes associated with meteorites and

ix xiii

1

1 7

17

impact phenomena? (K. W.R.Gilkes and C. T.Pillinger) 17 2.2. Other natural carbynoid structures (L.Kavan and R.B.Heimann) 31

Chapter 3: Syntheses of carbyne and carbynoid structures 39

3.1. Catalytic and electrochemical polycondensation reactions 39 3 .I.I.Dehydropolycondensation of acetylene (YlI.P.KlIdryavtsev) 39 3.1.2.Polycondensation reaction of halides (MKijima and

H.Shirakawa) 47 3.2. Chemical, photo-, and electrochemical transformations of

polymers 55 3.2. 1. Chemical dehydrohalogenation of polymers (S.E.Evsyukov) 55 3.2.2.Photo-and laser-induced dehydrohalogenation of polymers

(A.Yabe) 75 3.2.3.Dehydrogenation of poly acetylene at high static pressure

(J.A. Udod) 93 3.3. Pyrolytic methods

3.3 .I.Decomposition of hydrocarbons (A. Sokolowska and A.Olszyna) 117

3.3 .2.Pyrolysis of organic polymers (S.E.Evsyukov) 133 3.4. Phase transformation of carbon materials 139

3.4. 1. Condensation of carbon vapour 139

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3.4 .I.I.Resistive heating and laser irradiation (R.B.H eimann) 139 3.4. 1.2. Condensation of carbon vapor obtained by electrical arc

discharge (S.Tanuma) 149 3.4.2.Ion-assisted condensation of carbon (V.G.Babaev and

MB.Guseva) 159 3.4.3.Dynamic pressure synthesis (J.l.Kleiman, K. Yamada,

A.B.Sawaoka and R. B. Heimann) 173 3.5. Electrochemical methods (L.Kavan) 189

Chapter 4: Structural models of carbyne 215

4.1. Structural and electronic properties ofpolyyne (MSpringborg) 215 4.2. Kinked chains and layered structure (R.B.Heimann) 235 4.3. Carbyne intercalation compounds (l.A.Udod) 269 4.4. Electron diffraction and microscopy (A.F.Fitzgerald) 295

Chapter 5: Properties of carbyne and carbynoid structures

5.1. Chemical properties (S.E.Evsyukov) 5.2. Thermophysical properties (B. V.Lebedev) 5.3. Electrical and optical properties (E.MBaitinger)

Chapter 6: Molecular and electron spectroscopy of carbyne structures

309

309 317 333

343

6.1. Raman and infrared spectroscopy (L.Kavan and J.Kastner) 343 6.2. Electron spin resonance spectroscopy (D.P.Ertchak) 357 6.3. Electron spectroscopy (L.A.Pesin) 371 6.4. Electron energy loss spectroscopy studies of carbynoid

structures (J.l.Kleiman) 395

Chapter 7: Suggested technical applications of carbyne materials 409

7.1. Diamond synthesis from carbyne (R;B.Heimann) 409 7.2. Medical applications of carbynoid materials (V.l.Kirpatovsky) 427

LIST OF CONTRIBUTORS

Babaev, V.G. Department of Physics, Moscow State University, 119899 Moscow, Russia

e-mail: [email protected]

Baitinger, E.M. Department of Physics, Chelyabinsk State Pedagogical University,454080 Chelyabinsk, p.ussia


Ertchak, D.P. Department of Physics, Byelorussian State University, 220080 Minsk, Byelorussian Republic


Evsyukov, S.E. ( co-editor)

A.N.Nesmeyanov Institute of Organometallic Compounds, The Russian Academy of Sciences 117813 Moscow, Russia (on leave)

Present Address: BASF Aktiengesellschaft, Polymer Laboratory ZKS/A - B 1,67056 Ludwigshafen, Germany


Fitzgerald, A.G. Department of Applied Physics and Electronic & Mech. Eng., University of Dundee, Dundee DDl 4HN, Scotland, UK


Gilkes, K. Department of Earth Sciences, The Open University, Milton Hall Milton Keynes MK7 6AA, UK

Guseva, M.B. Department of Physics, Moscow State University, 119899 Moscow, Russia

e-mail: via V.G. Babaev ix

x

Heimann, R.B. (Editor-in-Chief)

Department of Mineralogy, Chair of Technical Mineralogy,

Kastner, J.

Kavan, L. (co-editor)

Kijima, M.

Freiberg University of Mining and Technology, 009599 Freiberg, Germany


PROF ACTOR Produktionsforschung GmbH, Wehrgrabengasse 1, A-54400 Steyr, Austria


J.Heyrovsky Institute of Physical Chemistry The Czech Academy of Sciences, 182 23 Prague 8, Czech Republic.


Institute of Materials Science, University of Tsukuba, Tsukuba, Ibaraki 305, Japan


Kirpatovsky, V.I. Laboratory for Experimental Modelling of Urological Diseases, Institute of Urology, 3rd Parkovaya str. 51, 105425 Moscow, Russia


Kleiman, J.I. Integrity Testing Laboratory Inc., c/o Institute for Aerospace Studies (UTIAS), University of Toronto, 4925 Dufferin Street, North York, Ontario, M3H 5T6 Canada


Kudryavtsev, Yu.P. A.N.Nesmeyanov Institute of Organoelement Compounds, The Russian Academy of Sciences, 117813 Moscow, Russia


xi

Lebedev, B.V. Scientific Research Institute of Chemistry, Nizhnii Novgorod State University, 603600 Nizhnii Novgorod, Russia


Olszyna, A. Warsaw University of Technology, Department of Materials Science and Engineering, 02-524 Warsaw, Poland


Pes in, L.A. Department of Physics, Chelyabinsk State Pedagogical University, 454080 Chelyabinsk, Russia


Pillinger, C.T. Department of Earth Sciences The Open University, Milton Hall Milton Keynes MK7 6AA, UK


Sawaoka, A.B. Materials and Structures Laboratory Tokyo Institute of Technology, Midori, Yokohama 226, Japan


Shirakawa, H. Institute of Materials Science, University of Tsukuba, Tsukuba,Ibaraki305,Japan


Sokolowska, A. Warsaw University of Technology, Department of Materials Science and Engineering, 02-524 Warsaw, Poland


Springborg, M. Fakultat fur Chemie, Universitat Konstanz, D7750 Konstanz, Germany


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Tanuma, S.

Udod,I.A.

College of Science and Engineering, Iwaki Meisei University, Iwaki 970, Japan

Department of Chemistry, Moscow State University, Moscow, Russia (on leave)

Present Address: Allied Signal Inc., 101 Columbia Rd., Morristown, NJ 07962, USA


Yabe, A. National Institute of Materials and Chemical Research (NIMC), Tsukuba, Ibaraki 305, Japan


Yamada, K. Department of Chemistry, The National Defence Academy, Hasirimizu, Yokosuka 239, Japan

Preface

"There are more things in heaven and Earth, Horatio, than are dreamt of in your philosophy" (Hamlet, 1st act, 5th scene)

CARBYNE AND CARBYNOID STRUCTURES

The chemistry and materials science of carbon is a fascinating field of endeavour with a plethora of technological applications ever since Tennant in 1797 experimentally proved that diamond is an allotrope of carbon. The history of the synthesis of diamond, the application of carbon fibers for mechanically superior composite materials, the research into intercalated graphite structures, and the recent discovery and exploration of fullerenes and fullerenoids are but a few highlights of this development.

Much less known is the fact that besides the well-known and copiously researched carbon allotropes graphite with sp2 - and diamond with sp3- carbon bond hybridization an allotrope seems to exists with linear sp-carbon bond hybridization that was discovered only in 1960 (Chapter 1.1.). Linear carbon chains with sp-hybridization are present in carbon vapour above 5000 K as well as in molecular clouds and cool carbon stars. Curiously, the search for such molecules triggered the discovery of fullerenes. However, it is an irony of science that fullerenes were never directly observed in outer space to date (Chapter 2.1.). On the other hand, carbyne was discovered in terrestrial impact craters, and related organic structure can be found ubiquituously in biological species (Chapter 2.2.).

The classification scheme of carbon allotropes based on the concept of the hybridization type of the valence orbitals of the carbon atoms was later confirmed by the discovery of mixed bonding types, and graphite and graphene intercalation compounds. The relationship of differently hybridized carbon allotropes is shown in the figure below.

Since there was, and still is a strong resistance, chiefly among organic chemists, to accept carbyne as a stable allotrope of carbon because of the notorious reactivity of carbon double and triple bonds, much work was expended to confirm its existence. Consequently there exists a rich but still higblycontroversial literature that also includes technological applications of carbyne and carbyne-like materials. Today some researchers consider carbyne the "third allotrope of carbon" even though no

xiii

XIV

unambiguous evidence for its existence as a bulk material is available yet (Chapter l.2.).

Diamond Lonsdaleite

\ , "Amorphous

carbon"

; /\ condensation A Vitreous

Po/ycyl:lc " carbon nllworks Grap/Ien"

./

Mo~cydic _ Graphynes- Layer-chaln Carbyne nngs, carbons mLCp

cydOn(N1carbons (m=2,O<p<1)

Nevertheless, a sizeable portion of the papers dealing with carbyne continned the presence of linear sp-hybridized carbon chains in the solid state, in which the carbon atoms are connected either by conjugated triple bonds (polyyne-type isomer) or cumulated double bonds (polycumulene-type isomer). Many ways to synthesize carbyne were explored by polymer scientists and solid state chemists during the last thirty five years (Chapter 3).

It was found that carbyne sensu strictu can be obtained today only by condensation of carbon vapour (Chapters 3.4.l., 3.4.2.), whereas chemical degradation reactions of polymers with a sizeable portion of conjugated multiple carbon bonds generally lead to carbynoid structures (Chapters 3.2., 3.3.2., 3.5.). These structures can be defined as carbon-rich chain-like poly( or oligo )mers with both polyyne- and cumulene-type moieties, extended interchain cross-linking as well as end-capping and/or pendant side groups, and intercalated larger atoms or ions to stablized the conformation. Hence these structures would hardly qualify for a carbon allotrope.

On the other hand, products obtained by condensation of carbon vapour (Chapters 3.4.1., 3.4.2.) under closely controlled conditions in an vacuum or inert gas environment approach the proposed ideal structural conformation of carbyne to a high degree. Long carbon chains terminated by stabilizing bulky organic groups or larger atoms and assembled in a van der Waals-bonded parallel array with occasional crosslinking could be considered a 'pure' carbon allotrope whose surface is terminated

xv

by heteroatoms the same way the surfaces of graphite and diamond are terminated by oxygen atoms and hydroxyl group to satisfy free, i.e. dangling bonds (Chapter 4).

Recently the carbyne research was pointed in a new direction. A series of papers were published dealing with potentially novel technological applications of carbyne intercalation compounds (CIC's) in the field of electrical and electronic devices (Chapter 4.3.). The intercalation of alkali metal atoms appears to split longer carbon chains of the precursor into shorter segments that form a 2D-lattice with allegedly tetragonal symmetIy. Treatment with mineral acids leads to residual intercalation compounds in which metal atoms at the ends of the short chains prevent lateral crosslinking thus stabilizing the sp-hybridized carbyne structure. According to these studies carbyne can be considered a quasicrystalline structure with long range order in <hk.O> direction but short range order in <00.1> direction parallel to the chains.

Very recent work showed that it is possible to synthesize, by a modified KriitschmerHuffinann experiment, carbyne with a chain length n> 100 using a "capping" reaction of reactive conjugated acetylene units with trifluoromethyl and cyano radicals. Since similar experiments were performed to synthesize fullerenes, interesting parallels abound. The explanation of the reaction involves the easy low activation energy transformation of polycyclic polyyne ring isomers into CSO-C76 fullerenes by a "spiraland-zipper" mechanism.

In the course of research on shock-induced transformation of graphite to diamond (Chapter 3.4.3.), several carbyne polytypes with various carbon chain conjugation lengths and bonding type were discovered in the shock-compressed products and classified by a novel model (Chapter 7.1.). This initially phenomenological model of the carbyne conformation explained not only the lattice metric of crystalline carbyne by the existence of carbon chains with differing numbers of carbon atoms but also postulated stiff linear carbon chains arranged in parallel fashion along the c-axis of the carbyne structure and held together rather loosely by van der Waals forces and lateral crosslinks, respectively.

Because the carbon chains are thought to contain kinks, carbynes may form sheet structures in which the carbon chains of adjacent sheets are offset by "kinks". This kink model explains rather well many properties of carbyne, and recently several authors were able to confirm this heuristic model theoretically and experimentally (Chapter 4.2.).

Since then the heuristic-speculative kink hypothesis is being improved and expanded. Based on theoretical calculations it was assumed, and later tentatively confirmed by experimental means, that spin density waves and solitons, respectively exist in the polyyne chains that can travel along the one-dimensional carbon chain. Such waves modulate the electron density and shift carbon atoms to new equilibrium positions. Strong electron-phonon coupling is presumably the driving force for a commensurate-incommensurate transition whose elastic term leads to lattice kinks. These lattice kinks are the domain walls of the transition, and hence the soliton separates two energetically equivalent but structurally different segments of the

xvi

polyyne chain, i.e. the postulated "kinks". This explanation was confirmed in part by a Patterson synthesis of electron density measurements in carbyne and by ESR studies of oriented carbyne films, that revealed a spin-Peierls soliton lattice (Chapter 6.2.).

As an interesting new aspect of a structural model of carbyne appears the notion that carbyne may be related to chiral poly(diacetylene). Indeed, the comparison of the lattice constants of different carbyne polytypic forms reported in the literature with the lattice constants of chiral poly( diacetylene) shows close similarities. This conjecture is also confirmed by the frequently observed fact that the structural building unit of carbyne may be a linear string of just four carbon atoms (diacetylene or butadiynyl units) (Chapter 4.2.).

The unambiguous chemical and physical characterization of such materials with lowdimensional structures is difficult and loaded with contradictions. The extremely small carbyne crystals formed during the syntheses approaches described in Chapter 3 were predominantly identified and classified by electron diffraction studies, and microscopic and microprobe techniques (Chapter 4.4.). Because carbyne crystals with well-defined structure and sufficient size are not available to date, complete x-ray diffraction analyses are still lacking. This is indeed the major obstacle to general acceptance of carbyne as a true carbon allotrope (Chapter l.2.). Instead, molecular and electron spectroscopy is widely used to characterize carbynoid materials, i.e., amorphous and/or mesoscopic solids with short-range order containing carbon chains of varying lengths and bond multiplicity (Chapter 6). Not only the smallness of the crystals but also their impurity content and inhomogeneities in the carbon skeleton make the study of all chemical and physical properties complex and the interpretation of the results subject to debate (Chapters 5 and 6).

Notwithstanding these limitations carbyne may have exciting practical applications as precursor materials for diamond (Chapter 7.1.) and biocompatible material for use in reconstructive surgery (Chapter 7.2.).

Challenging tasks are still ahead, and despite a host of papers dealing with different aspects of the physics and chemistry of carbyne, many questions remain to be solved. We believe that a critical assessment of these papers is required but we also emphasize that continuing efforts will eventually result in carbyne single crystals large enough to permit in-depth structural analysis. Hence it is not the intention of this text to reveal completely new and stunning research results on carbyne but to provide a rather complete, ordered and concise summary of what is known with certainty today and what is still ambiguous or downright wrong. Hence this book should be considered an important stepping stone towards an understanding of carbyne, an aspect many researchers around the world have attempted hitherto. It endeavours to show the research community what has been confirmed, what is still doubtful, what is or was wrong, and most importantly, where do we go from here. As the reader will easily notice, there are some overlaps among the individual contributions to this book. While in a multi-authored text dealing with the same class of materials overlaps can never be

xvii

completely avoided, we consider most of these overlaps fortuitous in that they allow to view many aspects of the subject matter from different angles. Thus we are left with a multifaceted approach to carbyne that will hopefully assist in charting a course towards future endeavours in the field of one of the most fascinating and controversial carbon allotropes in existence.

Since the opinions expressed in the individual chapters are those of the authors, they do not necessarily reflect those of the editors. However, we are proud to have succeeded in assembling a distinguished board of contributors. The text is a joint international endeavour of scientists from many countries: nine authors come from Russia, six from Japan, three from the United Kingdom, two each from Poland and Germany, and one each from Austria, Belorussia, Canada and the Czech Republic.

Many people assisted the editors in many stages of the preparation of this text. In particular, we are very much indebted to Ms. Jutta Hofmann of the Department of Mineralogy, Freiberg University of Mining and Technology for her very dedicated and able help in editing many chapters.

June 1998

Robert B.Heimann, Freiberg Sergey E.Evsyukov, Ludwigshafen Ladislav Kavan, Prague

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