Principles of Organometallic

Chemistry

P. POWELL

Principles of Organometallic

Chemistry

Second edition

Springer -Sciencet B usiness Media, B. V.

© 1988 P. Powell Originally published by Chapman and Hall

Softcover reprint of the hardcover 2nd edition 1988

ISBN 978-94-010-7032-4 ISBN 978-94-009-1197-0 (eBook) DOI 10.1007/978-94-009-1197-0

This title is available in both hardbound and paperback editions. The paperback edition is sold subject to the condition that it shall not, by way of trade or otherwise, be lent. resold, hired out, or otherwise circulated without the publisher's prior consent in any form ofbinding or cover other than that in which it is published and without a similar condition including this condition being imposed on the subsequent purchaser. Ali rights reserved. No part of this book may be reprinted, or reproduced or utilized in any form or by any electronic, mechanical or other means, now known or hereafter invented, including photocopying and recording, or in any information storage and retrieval system, without permission in writing from the publisher.

British Library Cataloguing in Publication Data

Powell. P. Principles of organometallic chemistry. -2nd ed. 1. Organometallic compounds !. Title 547'.05 QD4ll

Library of Congress Cataloging in Publication Data

Powell. P. (Paul). 1936-Principles of organometallic chemistry 1 P. Powell.-2nd ed.

p.cm. Rev. ed. of: Principles of organometallic chemistry 1 G.E. Coates

··· [et al.] .. 1968. Includes bibliographies and index.

l. Organometallic chemistry. !. Principles of organometallic chemistry. Il. Title. QD41l.P64 1988 87-17193 547'.05-dc 19 CIP

Contents

Foreword Preface Periodic table of the elements

1. General survey 1.1 Introduction 1.2 Historical background

ix xi

xiii

1 1 1

1. 3 Properties 2 1.4 Classification of organometallic compounds by bond type 2 1.5 The 'stability' of organometallic compounds 9 1.6 References 13

2. Methods of formation of metal-carbon bonds of the main group elements 15

2.1 The reaction between a metal and an organic halogen compound 15

2.2 Metal exchange: the reaction between a metal and an organometallic compound of another metal 19

2.3 Reactions of organometallic compounds with metal halides 20 2.4 Addition of metal hydrides to alkenes and alkynes 22 2.5 Formation of metal-carbon bonds by other insertion

reactions 2.6 Reactions of diazo compounds 2. 7 Decarboxylation of heavy B-metal salts 2.8 References

3. Organometallic compounds of elements of the first three

25 25 27 28

periodic groups 29 3.1 Introduction 29 3. 2 Structures 31 3.3 Alkali-metal derivatives 39 3.4 Grignard reagents 50

V

Contents

3.5 Beryllium 54 3.6 Calcium, strontium and barium 56 3. 7 Zinc, cadmium and mercury 5 7 3.8 Organoboron compounds 65 3. 9 Organometallic compounds of Al, Ga, In and TI 80 3.10 Organocopper and -silver compounds 87 3.11 Complexes of main group elements with unsaturated

hydrocarbons 90 3.12 References 94

Problems 95

4. Organometallic compounds of elements of main Groups IV and V 98

4.1 Introduction 98 4.2 Tetra-alkyls and -aryls of the elements of Group IV 99 4.3 Organohalides of the elements of Group IV 102 4.4 Silicones 109 4.5 Hydrolysis of organohalides of germanium, tin and lead 116 4.6 Catenated organic derivatives of the elements of Group IV 117 4.7 Divalent organic compounds of the elements of Group IV 121 4.8 pn-pn Bonding in compounds of Groups IV and V 124 4. 9 Organic derivatives of the elements of Group V 12 5 4.10 References 144

Problems 14 5

5. Some transition metal chemistry relevant to organometallic chemistry 148

5.1 The 18-electron rule 148 5.2 Transition metal carbonyls 152 5.3 Some general reactions of transition metal complexes 173 5.4 References 186

Problems 18 7

6. Organometallic compounds of the transition elements. Classification of ligands and theories of bonding 191

6.1 Classification of ligands 191 6.2 Molecular orbital theory 194 6.3 References 211

Problems 211

7. Organotransition metal chemistry. Alkyl and alkylidene derivatives. Complexes of alkenes and alkynes 213

7.1 Alkyls and aryls 213 7.2 Alkylidene and alkylidyne (carbene and carbyne)

complexes 232

vi

Contents

7.3 Complexes of alkenes 7.4 Complexes of alkynes 7. 5 References

Problems

237 243 248 249

8. Allyl and diene complexes of the transition elements 253 8.1 Allyl ( -enyl) complexes 2 5 3 8.2 Diene complexes 263 8.3 References 272

Problems 2 7 2

9. Five electron ligands 278 9.1 Introduction 278 9.2 Bis(cyclopentadienyl) complexes- the metallocenes 279 9.3 Cyclopentadienylmetal carbonyls 292 9.4 Open-chain (acyclic) pentadienyl complexes 301 9.5 Cyclohexadienyltricarbonyliron salts 303 9.6 References 304

Problems 30 5

1 O. Complexes of arenes 311 10.1 Bis( arene )complexes 311 10.2 Arene(tricarbonyl)chromium complexes 316 10.3 Chemistry of some arene complexes of iron 320 10.4 Nucleophilic attack on organotransition metal complexes 321 10.5 tJ 6 -Cycloheptatriene and ry 7-tropylium complexes 330 10.6 References 331

Problems 3 32

11. Cluster compounds 3 3 5 11.1 Introduction 335 11.2 11.3 11.4 11.5 11.6 11.7

Structure and bonding Carboranes Metallocarboranes and metalloboranes Transition metal clusters Clusters and catalysis References Problems

12. Mechanisms of industrial processes clarified by studies of homogeneous catalysis by complexes of transition elements 12.1 Introduction 12.2 Resources 12.3 Catalysis of reactions of alkenes by transition metal

complexes

335 340 344 348 352 355 355

357 357 361

361

vii

Contents

12.4 Chemistry based on synthesis gas 12.5 Conclusion 12.6 References

Problems

13. Some complexes of the lanthanides and actinides 13.1 Introduction -lanthanides

viii

13.2 Introduction-actinides 13.3 Cyclopentadienyls 13.4 Cyclooctatetraene complexes 13.5 References

Index

383 395 395 397

399 399 400 400 402 403

405

Foreword

The teaching of chemistry to undergraduate students presents course-content problems which grow ever more difficult as huge amounts of new material are added yearly to the overall body of the subject.

Some fifty years ago a student graduating with a good quality degree in chemistry could be expected to ha ve a reasonable grasp of most areas, including a fair number of recent developments. Sin ce then, the explosion of knowledge has made any such expectation quite unrealistic. Teachers of the subject continue, however. to need texts to which they can refer students. The excellent but mammoth compendia are clearly unsuitable for anything but reference.

Dr Powell's book provides a suitable anchor for students aiming at a useful grasp of organometallic chemistry, especially that of the transition elements. Applications of chemistry to industry often feature negligibly in undergraduate courses; the chapter on industrial processes should help to remedy this unfortunate situation.

The growth of organometallic chemistry over the past 40-50 years has been immense. The present book can trace its ancestry to a 'slim volume' published in 19 5 5, almost the whole of the very short chapter on transition metals having been added in the proof stage in 19 54. The third edition, written by three authors, devoted an entire volume to transition metals. After the publication of this two volume work, its authors decided that the book was no longer suitable for most students, and that a text aimed at undergraduate students should be written. Dr Powell was o ne of the four authors ofthe resulting book ( 19 68 ), and the present volume stems from it.

G.E. Coates, M.L.H. Green and K. Wade

ix

Preface

In the 20 years since 'Principles' first appeared the field of organometallic chemistry has continued to expand very rapidly. During the 1950s and 1960s the main theme was the preparation and structural characterization of new compounds, especially those ofthe transition elements. The last two decades ha ve seen the development of this theme and many unexpected materials such as carbyne complexes and cluster compounds have been discovered. There is now increasing emphasis on the application of organometallics of al! types in organic synthesis, both in the laboratory and on an industrial scale.

These developments, although very exciting, present problems to anyone rash enough to attempt to write an undergraduate text. Such a book should not be too long and should present a balanced view ofthe field without becoming completely indigestible through a mass of detail. The excellent reference work, 'Comprehen­sive Organometallic Chemistry', published in 1 9 8 2, consists of 8 tomes and a large index volume. Unfortunately, as Professor Coates has' remarked, "though the content of science has grown so much, it is unlikely that the effective capacity of students' brains has increased substantially over the past 15-20 years."

It has therefore been necessary to be very selective in the topics discussed. Emphasis is laid on structures, bonding, methods of preparation and general reactions of organometallic compounds. An elementary knowledge of thermody­namics, bonding theory and the use of spectroscopic methods of structure determination is assumed. The Periodic Groups provide a logica! framework for treating the compounds of the typical elements. In the area of the transition elements, however, the chemistry has been classified in terms of the electron number of the principal ligand. The alternative approach, classification by reaction type, can have the disadvantage that examples have to be drawn from otherwise unrelated areas, which can prove confusing to the beginner.

The relevance of organometallic chemistry to industry has been indicated throughout. Thanks are duc to severa! firms including Associated Octel. Bayer AG, British Petroleum pic, Dow Corning, Esso and Thomas Swan & Co. Ltd. for providing information in this connection. A chapter describes studies of the mechanisms of homogeneously catalysed reactions. A few of these reactions are used in industry. In other cases such mechanistic studies help to clarify how the related heterogeneous systems, which are used in practice, may work.

xi

Preface

Some modern uses of organometallic compounds in specific organic synthesis are indicated. Examples from natural product chemistry have mostly been omitted, because at undergraduate level they may divert attention from the main point.

Study problems ha ve been included at the end of chapters 3-12. A number of these derive from the finals pa pers of various UK universities. In these cases the name of the university is given at the end of the question, which bas been reproduced by kind permission of that institution. A booklet containing answers to these problems may be obtained by writing directly to the publishers.

Undergraduate students have little time to consult research papers or even review articles. Consequently only a few references to textbooks and recent reviews are given. Sources of further information are indicated, however, for those who need them.

I am most grateful to Professor J.A. Connor, Professor T. Edmonds, Dr P.I. Gardner, Dr M.L.H. Green, Dr P.G. Harrison and Dr D.M.P. Mingos for their helpful suggestions during the preparation of the manuscript. I should like especially to thank Professor G.E. Coates who read the complete text and made many valuable comments. I would also like to thank the staff at Chapman and Hali Ltd for their help and guidance during the production of the book.

P. Powell Royal Holloway and Bedford New College, University of London ]anuary 1988

xii

Periodic table of the elements

The periodic table overleafhas been included to give atomic weights for use in the problems at the ends of chapters 3-12. These weights have been taken from the IUPAC Inorganic Chemistry Division Commission on Atomic Weights and Isotopic Abundances published in 1986 in Pure and Applied Chemistry, 58, 16 77-9 2. Brackets indicate that the weight of the commonest nuclide has been given for a non-naturally occurring element.

xiii

Periodic table of elements

Period Group Group Group Group Group Group Group Group la Ilo !Ilo IVa Va Via VIla VIII

1 1 1 1 1 1 H

1 1 1 1

1s 1 1

1 1 1 1 1.01 1 1 1 1

1 1 1

3 4 1 1 1

2 Li Be 1 1 1

2s 2p 1 1 1

1 1

6.94 9.01 1 1

1

1 1

1

11 12 1 1 1

3 1 1 1

1

3s 3p Na Mg 1 1 1 1

1

1 1 1 1 1

22.99 24.31 1 1 1 1 1

4 19 20 21 22 23 24 25 26 27 28

4s 3d4p K Ca Se Ti V Cr Mn Fe Co Ni

39.10 40.08 44.96 47.88 50.94 52.00 54.94 55.85 58.93 58.69

5 37 38 39 40 41 42 43 44 45 46

5s4d5p Rb Sr y Zr Nb Mo Te Ru Rh Pd

85.47 87.62 88.91 91.22 92.91 95.94 (99) 101.07 102.91 106.42

6 55 56 57* 72 73 74 75 76 77 78

6s (4fl Cs Ba La Hf Ta w Re Os lr Pt-5d6p

132.91 137.32 138.91 178.49 180.95 183.85 186.21 190.20 192.22 195.08

7 87 88 89**

7s (5f) Fr Ro Ac 6d (223) (226) (227)

*Lanthanide 58 59 60 61 62 63 64 65

series Ce Pr Nd Pm Sm Eu Gd Tb

4f 140.12 140.91 144.24 (145) 150.36 151.97 157.25 158.93

**Achnide 90 91 92 93 94 95 96 97

series Th Pa u Np Pu Am Cm Bk

Sf 232 231 238 (237) (244) (243) (247) (247)

xiv

Periodic table of elements

Group Group Group Group Group Group Group Group lb llb lllb IVb Vb Vlb Vllb o

1 1 1 1 2 1 1 1 H He 1 1 1 1 1

1 1 1 1.01 4.. 00 1

1 5 6 7 8 9 10 1 1 8 c N 1

o F Ne 1 10.81 12.01 14..01 16.00 19.00 20.18 1 1 13 14 15 16 17 18 1 1 Al Si p s CI Ar 1 1 26.98 28.09 30.97 32.07 35.45 39.95 1

29 30 31 32 33 34 35 36

Cu Zn Ga Ge As Se Br Kr 63.55 65.39 69.72 72.61 74.92 78.96 79.90 83.80

47 48 49 50 51 52 53 54

Ag Cd In Sn Sb Te 1 Xe 107.87 112.41 114.82 118.71 121.75 127.60 126.90 131.29

79 80 81 82 83 84 85 86

Au Hg TI Pb Bi Po M Rn

196.97 200.59 204.38 207.20 208.98 [-210) (-210) (-222)

66 67 68 69 70 71

Dy Ho Er Tm Yb Lu

162.50 164.93 167. 26 168.93 173.04 174.97

98 99 100 101 102 103

Cf Es Fm Md No Lr (251) (252) [257) (258) (259) [260)

XV