HYPERCARBON CHEMISTRY HYPERCARBON CHEMISTRY Second Edition GEORGE A OLAH G K SURYA PRAKASH KENNETH WADE ÁRPÁD MOLNÁR ROBERT E WILLIAMS A JOHN WILEY & SONS, INC., PUBLICATION Copyright © 2011 by John Wiley & Sons, Inc All rights reserved Published by John Wiley & Sons, Inc., Hoboken, New Jersey Published simultaneously in Canada No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, scanning, or otherwise, except as permitted under Section 107 or 108 of the 1976 United States Copyright Act, without either the prior written permission of the Publisher, or authorization through payment of the appropriate per-copy fee to the Copyright Clearance Center, Inc., 222 Rosewood Drive, Danvers, MA 01923, (978) 750-8400, fax (978) 750-4470, or on the web at www.copyright.com Requests to the Publisher for permission should be addressed to the Permissions Department, John Wiley & Sons, 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Customer Care Department within the United States at (800) 762-2974, outside the United States at (317) 572-3993 or fax (317) 572-4002 Wiley also publishes its books in a variety of electronic formats Some content that appears in print may not be available in electronic formats For more information about Wiley products, visit our web site at www.wiley.com Library of Congress Cataloging-in-Publication Data: Hypercarbon chemistry / by George A Olah [et al.] – 2nd ed p cm Includes index ISBN 978-0-470-93568-2 (cloth) Carbonium ions Organometallic chemistry I Olah, George A (George Andrew), 1927QD305.C3H97 2011 547.01–dc22 2010044306 Printed in the United States of America ePDF ISBN 9781118016442 ePub ISBN 9781118016459 oBook ISBN 9781118016466 10 In Memory of the Late Professor William N Lipscomb CONTENTS Foreword to the First Edition xiii Preface to the Second Edition xv Preface to the First Edition Introduction: General Aspects 1.1 1.2 1.3 1.4 Aims and Objectives Some Definitions Structures of Some Typical Hypercarbon Systems The Three-Center Bond Concept: Types of Three-Center Bonds 1.5 The Bonding in More Highly Delocalized Systems 1.6 Reactions Involving Hypercarbon Intermediates References Carbon-Bridged (Associated) Metal Alkyls 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 Introduction Bridged Organoaluminum Compounds Beryllium and Magnesium Compounds Organolithium Compounds Organocopper, Silver, and Gold Compounds Scandium, Yttrium, and Lanthanide Compounds Titanium, Zirconium, and Hafnium Compounds Manganese Compounds Other Metal Compounds with Bridging Alkyl Groups xvii 1 10 21 26 31 37 37 41 50 53 58 62 64 66 68 vii viii CONTENTS 2.10 Agostic Systems Containing Carbon–Hydrogen–Metal 3c–2e Bonds 2.11 Conclusions References Carboranes and Metallacarboranes 3.1 Introduction 3.2 Carborane Structures and Skeletal Electron Numbers 3.2.1 Closo Carboranes 3.2.2 Nido and Arachno Carboranes 3.2.3 Carbon Sites in Carboranes; Skeletal Connectivities k 3.2.4 Skeletal Bond Orders in Boranes and Carboranes 3.3 Localized Bond Schemes for Closo Boranes and Carboranes 3.3.1 Lipscomb’s Styx Rules and Williams’ Stx Rules 3.3.2 Bond Orders and Skeletal Connectivities 3.3.3 Bond Networks and Skeletal Connectivities 3.3.4 Calculated Charge Distributions and Edge Bond Orders 3.4 MO Treatments of Closo Boranes and Carboranes 3.5 The Bonding in Nido and Arachno Carboranes 3.5.1 Localized Bond Schemes 3.5.2 MO Treatments of Nido and Arachno Boranes and Carboranes 3.5.3 Some Boron-Free Nido and Arachno Systems 3.6 Methods of Synthesis and Interconversion Reactions 3.7 Some Carbon-Derivatized Carboranes 3.7.1 Carboranyl C–H -X Hydrogen-Bonded Systems 3.7.2 Carboranyl–Metal Systems 3.7.3 Some Aryl-Carboranes 3.8 Boron-Derivatized Carboranes: Weakly Basic Anions [CB11H6X6]− 3.9 Metallacarboranes 3.9.1 Structural Types, Electron Counts, and Isolobal Units 3.9.2 Predicting Structures from Formulae 3.9.3 Metal Complexes of CxBy Ring Systems 3.10 Supraicosahedral Carborane Systems 3.11 Conclusions References Mixed Metal–Carbon Clusters and Metal Carbides 4.1 Introduction 4.2 Complexes of CnHn Ring Systems with a Metal Atom: Nido-Shaped MCn Clusters 4.3 Metal Complexes of Acyclic Unsaturated Ligands, CnHn+2 70 76 77 85 85 87 88 89 97 98 98 98 100 101 102 104 107 107 108 110 111 114 114 114 116 122 123 123 126 130 133 137 137 149 149 150 157 CONTENTS 4.4 Complexes of Unsaturated Organic Ligands with Two or More Metal Atoms: Mixed Metal–Carbon Clusters 4.5 Metal Clusters Incorporating Core Hypercarbon Atoms 4.6 Bulk Metal Carbides 4.7 Metallated Carbocations 4.8 Conclusions References Hypercoordinate Carbocations and Their Borane Analogs 5.1 General Concept of Carbocations: Carbenium Versus Carbonium Ions 5.1.1 Trivalent–Tricoordinate (Classical) Carbenium Ions 5.1.2 Hypercoordinate (Nonclassical) Carbonium Ions 5.2 Methods of Generating Hypercoordinate Carbocations 5.3 Methods Used to Study Hypercoordinate Carbocations 5.3.1 NMR Spectroscopy in Solution 5.3.2 13C NMR Chemical Shift Additivity 5.3.3 Isotopic Perturbation Method 5.3.4 Solid-State 13C NMR at Extremely Low Temperature 5.3.5 X-Ray Diffraction 5.3.6 Tool of Increasing Electron Demand 5.3.7 ESCA 5.3.8 Low Temperature Solution Calorimetry 5.3.9 Quantum Mechanical Calculations 5.4 Methonium Ion (CH5+) and Its Analogs 5.4.1 Alkonium Ions Incorporating Bridging Hydrogens (Protonated Alkanes, CnH2n+3+) 5.4.1.1 The Methonium Ion (CH5+) 5.4.1.2 Multiply-Protonated Methane Ions and their Analogs 5.4.1.3 Varied Methane Cations 5.4.1.4 Ethonium Ion (C2H7+) and Analogs 5.4.1.5 Proponium Ions and Analogs 5.4.1.6 Higher Alkonium Ions 5.4.1.7 Adamantonium Ions 5.4.1.8 Hydrogen-Bridged Cycloalkonium Ions 5.4.1.9 Hydrogen-Bridged Acyclic Ions 5.4.1.10 Five-Center, Four-Electron Bonding Structures 5.4.2 Hypercoordinate Carbocations Containing 3c–2e C -C -C Bonds 5.4.2.1 Cyclopropylmethyl and Cyclobutyl Cations 5.4.2.2 The 2-Norbornyl Cation 5.4.2.3 The 7-Norbornyl Cation 5.4.2.4 The 2-Bicyclo[2.1.1]hexyl Cation 5.4.2.5 The Polymethyl 2-Adamantyl Cations ix 160 162 173 176 176 177 185 185 186 187 188 189 189 192 192 193 193 194 194 195 195 195 195 196 202 205 208 210 211 217 217 221 223 223 223 229 243 243 245 x CONTENTS 5.5 Homoaromatic Cations 5.5.1 Monohomoaromatic Cations 5.5.2 Bishomoaromatic Cations 5.5.3 Trishomoaromatic Cations 5.5.4 Three-Dimensional Homoaromaticity 5.5.5 Möbius Homoaromaticity 5.6 Hypercoordinate (Nonclassical) Pyramidal Carbocations 5.6.1 (CH)5+-Type Cations 5.6.2 (CH)62+-Type Dications 5.7 Hypercoordinate Heterocations 5.7.1 Introduction 5.7.2 Hydrogen-Bridged Silyl Cations 5.7.3 Homoaromatic Heterocations 5.8 Carbocation–Borane Analogs 5.8.1 Introduction 5.8.2 Hypercoordinate Methonium and Boronium Ions 5.8.3 Cage Systems 5.8.4 Hypercoordinate Onium–Carbonium Dications and Isoelectronic Onium–Boronium Cations 5.9 Conclusions References Reactions Involving Hypercarbon Intermediates 6.1 Introduction 6.2 Reactions of Electrophiles with C–H and C–C Single Bonds 6.2.1 Acid-Catalyzed Reactions and Rearrangements of Alkanes, Cycloalkanes, and Related Compounds 6.2.1.1 Carbon–Hydrogen and Carbon–Carbon Bond Protolysis 6.2.1.2 Isomerization and Rearrangement 6.2.1.3 Alkylation 6.2.2 Nitration and Nitrosation 6.2.3 Halogenation 6.2.4 Carbonylation 6.2.5 Oxyfunctionalization 6.2.5.1 Oxygenation with Hydrogen Peroxide 6.2.5.2 Oxygenation with Ozone 6.2.5.3 Oxygenation with Other Reagents 6.2.6 Sulfuration 6.2.7 Reactions of Coordinatively Unsaturated Metal Compounds and Fragments with C–H and C–C σ Bonds 247 247 249 256 258 259 260 260 264 266 266 266 267 268 268 272 272 274 276 277 295 295 298 298 298 307 320 325 328 331 332 332 334 337 339 340 CONTENTS xi 6.2.7.1 Carbon–Hydrogen Bond Insertion 6.2.7.2 Carbon–Carbon Bond Insertion 6.2.8 Reactions of Singlet Carbenes, Nitrenes, and Heavy Carbene Analogs with C–H and C–C Bonds 6.2.9 Rearrangement to Electron-Deficient Metal, Nitrogen, and Oxygen Centers 6.2.9.1 Isomerization, Rearrangement, and Redistribution of Alkylmetal Compounds 6.2.9.2 Rearrangements to Electron-Deficient Nitrogen and Oxygen Centers 6.3 Electrophilic Reactions of π-Donor Systems 6.4 Bridging Hypercoordinate Species with Donor Atom Participation 6.4.1 Carbocations with 3c–2e Bond 6.4.2 Five-Coordinate SN2 Reaction Transition States and Claimed Intermediates 6.4.3 Six-Coordinate Hypervalent Compounds 6.5 Conclusions References 342 362 389 393 394 394 Conclusions and Outlook 417 Index 419 371 377 377 381 383 388 388 FOREWORD TO THE FIRST EDITION The periodic nature of the properties of atoms and the nature and chemistry of molecules are based on the wave property of matter and the associated energetics Concepts including the electron-pair bond between two atoms and the associated three-dimensional properties of molecules and reactions have served the chemist well, and will continue to so in the future The completely delocalized bonds of π-aromatic molecules, introduced by W Hückel, also provided a basis for a rational description of molecular orbitals in these systems An extended Hückel theory allowed a study of molecular orbitals throughout chemistry at a certain level of approximation The localized multicenter orbital holds a certain intermediate ground, and is particularly useful when there are more valence orbitals then electrons in a molecule or transition state First widely used in the boron hydrides and carboranes, these three-center and multicenter orbitals provide a coherent and consistent description of much of the structure and chemistry of the upper left side of the periodic table, and of the interactions of metallic ions with other atoms or molecules Skeletal electron counts (the sum of the styx numbers), first proposed by Wade, Mingos, and Rudolph, have also provided a guide for synthesis, and have given a basis for filled bonding description of polyhedral species and their fragments Together with the isolobal concept, diverse areas of chemistry have thereby been unified In this book, one sees the remarkable way in which these ideas bring together structure and reactivity in a great diversity of novel carbon chemistry and its relationship with that of boron, lithium, hydrogen, the metals, and others The authors are to be congratulated xiii ... First Edition xiii Preface to the Second Edition xv Preface to the First Edition Introduction: General Aspects 1.1 1.2 1.3 1.4 Aims and Objectives Some Definitions Structures of Some Typical Hypercarbon. .. THE SECOND EDITION More than 20 years have passed since the publication of our book on hypercarbon chemistry The book became out of print and much progress has since been made in the field Hypercarbon. . .HYPERCARBON CHEMISTRY Second Edition GEORGE A OLAH G K SURYA PRAKASH KENNETH WADE ÁRPÁD MOLNÁR ROBERT E WILLIAMS