Edited by William B.Tolman WILEY-VCH Activation of Small Molecules Organometallic and Bioinorganic Perspectives
The Editor Prof William B.Tolmar publisher do not warrant the information containec ity of Min Reade Library of Congress Card No.:applied for British Library Catalo ublished by lists this WILEYVCH Veng CmbCG du mbH,He Grafik-Design Schulz. ce pape
The Editor Prof. William B. Tolman Department of Chemistry University of Minnesota 207 Pleasant St. SE Minneapolis, MN 54555 USA Library of Congress Card No.: applied for British Library Cataloguing-in-Publication Data A catalogue record for this book is available from the British Library. Bibliographic information published by the Deutsche Nationalbibliothek The Deutsche Nationalbibliothek lists this publication in the Deutsche Nationalbibliografie; detailed bibliographic data are available in the Internet at http://dnb.d-nb.de. © 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim, Germany All rights reserved (including those of translation into other languages). No part of this book may be reproduced in any form – by photoprinting, microfilm, or any other means – nor transmitted or translated into a machine language without written permission from the publishers. Registered names, trademarks, etc. used in this book, even when not specifically marked as such, are not to be considered unprotected by law. Typsetting K+V Fotosatz GmbH, Beerfelden Printing Strauss GmbH, Mörlenbach Bookbinding Litges & Dopf Buchbinderei GmbH, Heppenheim Cover Design Grafik-Design Schulz, Fußgönheim Printed in the Federal Republic of Germany Printed on acid-free paper ISBN-13: 978-3-527-31312-9 ISBN-10: 3-527-31312-5 All books published by Wiley-VCH are carefully produced. Nevertheless, authors, editors, and publisher do not warrant the information contained in these books, including this book, to be free of errors. Readers are advised to keep in mind that statements, data, illustrations, procedural details or other items may inadvertently be inaccurate
Contents Preface XIII List of Contributors XV Carbon Dioxide Reduction and Uses as a Chemical Feedstock 1 Michele Aresta 1.1 Introduction 1 1.2 Properties of the CO2 Molecule 3 1.2.1 Molecular Geometry 3 122 Spectroscopic Properties 3 1221 Vibrational 3 1.2.2.2 UV-Vis 4 1.223 BC.Nuclear magnetic Reson 123 Data and Re. etics Rel 5 13 action of Cowith Metal Atoms at ow Temperature:Stabilit of the 13.3 Reactivity of CO2 Coordinated to Transition Metal Systems 8 1.4 CO,Conversion 9 1.4.1 Carboxylation Reactions 10 1.4.1.1 C-C Bond Formation 10 1.41.1.1 Natural Processes 11 1.4.1.1.2 Artificial Processes 12 1412 N-C Bond Formation 16 1413 O-C Bond Formation 18 1.4131 Cyclic Carbonates 18 14132 ates 1414 Use of Urea 26 1.4.15 as ap cation ns 1.4.2 Red action Reactions
Preface XIII List of Contributors XV 1 Carbon Dioxide Reduction and Uses as a Chemical Feedstock 1 Michele Aresta 1.1 Introduction 1 1.2 Properties of the CO2 Molecule 3 1.2.1 Molecular Geometry 3 1.2.2 Spectroscopic Properties 3 1.2.2.1 Vibrational 3 1.2.2.2 UV-Vis 4 1.2.2.3 13C-Nuclear Magnetic Resonance (NMR) 4 1.2.3 Energy Data and Reaction Kinetics Relevant to CO2 Conversion 5 1.3 CO2 Coordination to Metal Centers and Reactivity of Coordinated CO2 6 1.3.1 Modes of Coordination 6 1.3.2 Interaction of CO2 with Metal Atoms at Low Temperature: Stability of the Adducts 8 1.3.3 Reactivity of CO2 Coordinated to Transition Metal Systems 8 1.4 CO2 Conversion 9 1.4.1 Carboxylation Reactions 10 1.4.1.1 C–C Bond Formation 10 1.4.1.1.1 Natural Processes 11 1.4.1.1.2 Artificial Processes 12 1.4.1.2 N–C Bond Formation 16 1.4.1.3 O–C Bond Formation 18 1.4.1.3.1 Cyclic Carbonates 18 1.4.1.3.2 Linear Carbonates 22 1.4.1.4 Use of Urea as an Active-CO2 Form 26 1.4.1.5 Transesterification Reactions 27 1.4.2 Reduction Reactions 28 V Activation of Small Molecules. Edited by William B. Tolman Copyright © 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim ISBN: 3-527-31312-5 Contents
VI Contents 1.4.2.1 Energetics of the Reactions 28 14211 Natural Processes 28 1.4.2.1.2 Artificial Processes 29 1.4.2.1.3 Photoelectrochemical Reduction 33 1.5 Conclusions 34 Refere ces 2 Nitrogen Monoxide us Oxide Bindi ing and Reduction 4 Kenneth D.Karlin 2 Introduction 22 NO 44 2.2.1 Bonding and structures of metal Nitrosyls 44 2.2.1.1 Heme Proteins:Guanylate Cyclase-NO Binding and Trans-bond labilization 47 2.2.12 Bridging (nu)Complexes 49 2213 n-uNO Bridg ing Complexes 49 2)14 n.NO Bridging Complexes 50 2.2.1.5 Isonitrosyl and Side-onNO Comple xes 50 2.2.1.6 Side-on NO Coppe t Protein Structu res 51 2.2.1.7 of Nitr Metal Co of No mplexes 53 nd Related Che mistry Chemical Reduction of Metal und NO 21 I-NO Redu ction Ac NoN-O Cleavage 56 Electrophilic ttac HNO (Nitroxyl) Complexes 58 2.2.2.3 Electrocatalytic Reduction of NO 2.2.2.4 Biological NO Reduction:NORs 61 2.2.2.4.1 Bacterial NORs of the Heme Copper Oxidase(HCO)Type 61 2.2.2.4.2 Models for NORs 63 2.2.2.4.3 Fungal P450-type NORs 63 2.2.2.4.4 Flavorubredoxins as Scavenging(S)-NORs 64 2225 Metal Complex-mediated NO Disproportionation 65 23 N,066 2.3.1 Structure and Bonding 66 2.3.2 Metal- 68 sfer Re n 6 fe avage 70 Ele taly luction of N2O to N2 71 Biological N2O Reduction 4 Summary and Conclusions References
1.4.2.1 Energetics of the Reactions 28 1.4.2.1.1 Natural Processes 28 1.4.2.1.2 Artificial Processes 29 1.4.2.1.3 Photoelectrochemical Reduction 33 1.5 Conclusions 34 References 35 2 Nitrogen Monoxide and Nitrous Oxide Binding and Reduction 43 Dong-Heon Lee, Biplab Mondal, and Kenneth D. Karlin 2.1 Introduction 43 2.2 NO 44 2.2.1 Bonding and Structures of Metal Nitrosyls 44 2.2.1.1 Heme Proteins: Guanylate Cyclase – NO Binding and Trans-bond Labilization 47 2.2.1.2 Bridging (1 -2-) Complexes 49 2.2.1.3 1 -3-NO Bridging Complexes 49 2.2.1.4 2 -NO Bridging Complexes 50 2.2.1.5 Isonitrosyl and Side-on 2 -NO Complexes 50 2.2.1.6 Side-on 2 -NO Copper Protein Structures 51 2.2.1.7 Spectroscopic Features of Nitrosyl Metal Complexes 53 2.2.2 Chemical Reduction of NO and Related Chemistry 53 2.2.2.1 Chemical Reduction of Metal-bound NO 53 2.2.2.1.1 Metal–NO Reduction Accompanied by N–O Cleavage 56 2.2.2.2 Electrophilic Attack on Metal-bound NO :HNO (Nitroxyl) Complexes 58 2.2.2.3 Electrocatalytic Reduction of NO 60 2.2.2.4 Biological NO Reduction: NORs 61 2.2.2.4.1 Bacterial NORs of the Heme Copper Oxidase (HCO) Type 61 2.2.2.4.2 Models for NORs 63 2.2.2.4.3 Fungal P450-type NORs 63 2.2.2.4.4 Flavorubredoxins as Scavenging (S)-NORs 64 2.2.2.5 Metal Complex-mediated NO Disproportionation 65 2.3 N2O 66 2.3.1 Structure and Bonding 66 2.3.2 Metal-mediated N2O Reduction 68 2.3.2.1 Oxo Transfer Reactions 68 2.3.2.2 Catalytic Oxo Transfer 70 2.3.2.3 N2O N–N Bond Cleavage 70 2.3.2.4 Electrocatalytic Reduction of N2O to N2 71 2.3.2.5 Biological N2O Reduction 72 2.4 Summary and Conclusions 73 References 74 VI Contents
Contents VIl 3 Bio-organometallic Approaches to Nitrogen Fixation Chemistry 81 lonas C.Peters and Mark P.Mehn ntroduction-The N2 Fixation Challenge 81 32 Biological na Reduction 83 3.2.1 General Comments 83 3.2.2 Structural Data 84 3.23 Assigning the FeMoco Oxidation States 85 3.3 Biomimetic Systems that Model Structure and Function 86 331 General Comments 86 232 Mon clear molybde um Systems of Biomimetic Interest 86 2201 The Originally Proposed"Cha Cycle"87 3.3.22 An Ele ocatalytic A M()- med: ng Low-valent Tungsten 89 A Cp Me (Na)Model System (M Mo,W) 9 3.32 Bimetallic Mol m Systems that Cleave N2 93 3.32.6 Sulfur-supported Mo-N2 Complexes 95 3.3.3 Considering Mechanisms Involving Multiple and Single Iron Sites for N2 Reduction 96 3.3.3.1 General Comments 96 3.3.32 Theoretical Studies that Invoke Iron-mediated Mechanisms 96 3.3.3.2.1 3.333 Shncoculple ro Sle1 3334 Nitrogenase-related Transformations at Cluster Models 104 3339 Considering N.Fixation Involving a Scheme single iron Site 102 3.3.3.6 Model Studies that May be Relevant to N,Fixation Involving a Single Iron Site 108 3.3.3.61 Fe(0)-N2Co and NH,versus NaH Production 108 3.33.6.2 109 3.4 ordinate Iron Model Systems ences A The Activation of Dihydrogen Jesse W.Tye and Michael B.Hall 4.1 ntroduction 12 4.1.1 Why Activate H,?121 4.1.2 Why is it so Difficult to Activate H2?122 4.2 Structure and Bonding of Metal-bound H-Atoms 124 4.2.1 Why can Metal Centers React Directly with H2. yhile most Nonmetals Cannot?124 4)) Seminal Work:The Discovery of Metal-bound H2 Complexes 125 4.2.3 What are the possible co gely Uns 126 424 o 13g 4.25 of Activation esof the H Interaction and Degree
3 Bio-organometallic Approaches to Nitrogen Fixation Chemistry 81 Jonas C. Peters and Mark P. Mehn 3.1 Introduction – The N2 Fixation Challenge 81 3.2 Biological N2 Reduction 83 3.2.1 General Comments 83 3.2.2 Structural Data 84 3.2.3 Assigning the FeMoco Oxidation States 85 3.3 Biomimetic Systems that Model Structure and Function 86 3.3.1 General Comments 86 3.3.2 Mononuclear Molybdenum Systems of Biomimetic Interest 86 3.3.2.1 The Originally Proposed “Chatt Cycle” 87 3.3.2.2 An Electrocatalytic Reduction Cycle using Low-valent Tungsten 89 3.3.2.3 A Mo(III)-mediated Catalytic N2 Reduction System 90 3.3.2.4 A Cp*MMe3(N2) Model System (M = Mo, W) 92 3.3.2.5 Bimetallic Molybdenum Systems that Cleave N2 93 3.3.2.6 Sulfur-supported Mo-N2 Complexes 95 3.3.3 Considering Mechanisms Involving Multiple and Single Iron Sites for N2 Reduction 96 3.3.3.1 General Comments 96 3.3.3.2 Theoretical Studies that Invoke Iron-mediated Mechanisms 96 3.3.3.2.1 Comparing Several Proposed Mechanisms 97 3.3.3.3 Synthetic Efforts to Model N2 Reduction by Multiple Iron Sites 103 3.3.3.4 Nitrogenase-related Transformations at Cluster Models 104 3.3.3.5 Considering N2 Fixation Involving a Scheme Single Iron Site 107 3.3.3.6 Model Studies that May be Relevant to N2 Fixation Involving a Single Iron Site 108 3.3.3.6.1 Fe(0)-N2 Complexes and NH3 versus N2H4 Production 108 3.3.3.6.2 Low-coordinate Iron Model Systems 109 3.4 Concluding Remarks 115 References 116 4 The Activation of Dihydrogen 121 Jesse W. Tye and Michael B. Hall 4.1 Introduction 121 4.1.1 Why Activate H2? 121 4.1.2 Why is it so Difficult to Activate H2? 122 4.2 Structure and Bonding of Metal-bound H-Atoms 124 4.2.1 Why can Metal Centers React Directly with H2, while most Nonmetals Cannot? 124 4.2.2 Seminal Work: The Discovery of Metal-bound H2 Complexes 125 4.2.3 What are the Possible Consequences when H2 Approaches a Coordinatively Unsaturated Transition Metal Center? 126 4.2.4 Elongated 2 -H2 Complexes 128 4.2.5 Experimental Gauges of the H–H Interaction and Degree of Activation 129 Contents VII
Contents 4.2.5.1 Neutron Diffraction 129 4252 'H NMR Studies:HD Coupling 130 4.25.3 H NMR Studies:Proton Relaxation Time(T Measurements)130 42.5.4 IR and Raman Spectral Studies:v(H-H)Measurements 130 amolecular H-Aton 131 atio 132 change 135 Nor H-Bonds 44.1 Hydride Ligands as Nonclassical H-Bond Acceptors 136 4.42 y2.H2 as a Nonclassical H-Bond Donor 136 4.5 Reactivity of metal-bound H-Atoms 137 4.5.1 How Does the Reactivity of Metal-bound H-atoms Compare to that of Free h 137 4.5.2 Metal-Monohvdride species "Hydride Ligands can be Acidic!" 138 453 Increased Acidity of H,139 45.4 Seminal work:Intramolecular heterolvtic clea avage of H2 141 4.6 Recent Advances in the Activation of Dihydr V S mthetic Cor ptake by 14 142 encaps of H2 in Coo ersion of Bi mass to H2 First Group 5H2 Complex Enzymatically Catalyzed Dihydrogen Oxidation and Proton Reduction 142 4.7.1 General Information about H2ase Enzymes 143 4.7.11 [NiFe]Hzase 143 4.7.1.2 [FeFe]Hzase 145 4.7.2 H2 Production by Nase 148 4721 General Information about Nase Enzymes 148 4722 Molybdenum-Iron-containing Nzase 14g 4.8 Conclusions 149 Acknowledgments 150 Abbreviations 150 rences 150 5 Molecular Oxygen Bind Activation:Oxidation Catalysis 159 Candace N.Corne 5 Introduction Additive Coreductants 167 5.2.1 Aldehydes 161 5.2.2 Coupled Catalytic Systems 165 5.2.2.1 Organic Cocatalysts 166
4.2.5.1 Neutron Diffraction 129 4.2.5.2 1 H NMR Studies: HD Coupling 130 4.2.5.3 1 H NMR Studies: Proton Relaxation Time (T1 Measurements) 130 4.2.5.4 IR and Raman Spectral Studies: (H–H) Measurements 130 4.3 Intramolecular H-Atom Exchange 131 4.3.1 Rotation of 2 -H2 Ligands 132 4.3.2 H2/H– Exchange 134 4.3.3 Hydride–Hydride Exchange 135 4.4 Nonclassical H-Bonds 136 4.4.1 Hydride Ligands as Nonclassical H-Bond Acceptors 136 4.4.2 2 -H2 as a Nonclassical H-Bond Donor 136 4.5 Reactivity of Metal-bound H-Atoms 137 4.5.1 How Does the Reactivity of Metal-bound H-atoms Compare to that of Free H2? 137 4.5.2 Metal-Monohydride Species – “Hydride Ligands can be Acidic!” 138 4.5.3 Increased Acidity of 2 -H2 139 4.5.4 Seminal Work: Intramolecular Heterolytic Cleavage of H2 141 4.6 Recent Advances in the Activation of Dihydrogen by Synthetic Complexes 141 4.6.1 H2 Uptake by a Pt–Re Cluster 141 4.6.2 H2 Binding to IrIII Initiates Conversion of CF3 to CO 142 4.6.3 Encapsulation of H2 in C60 142 4.6.4 Conversion of Biomass to H2 142 4.6.5 First Group 5 2 -H2 Complex 142 4.7 Enzymatically Catalyzed Dihydrogen Oxidation and Proton Reduction 142 4.7.1 General Information about H2ase Enzymes 143 4.7.1.1 [NiFe]H2ase 143 4.7.1.2 [FeFe]H2ase 145 4.7.2 H2 Production by N2ase 148 4.7.2.1 General Information about N2ase Enzymes 148 4.7.2.2 Molybdenum–Iron-containing N2ase 149 4.8 Conclusions 149 Acknowledgments 150 Abbreviations 150 References 150 5 Molecular Oxygen Binding and Activation: Oxidation Catalysis 159 Candace N. Cornell and Matthew S. Sigman 5.1 Introduction 159 5.2 Additive Coreductants 161 5.2.1 Aldehydes 161 5.2.2 Coupled Catalytic Systems 165 5.2.2.1 Organic Cocatalysts 166 VIII Contents
Contents IX 5.22.2 Metal Cocatalysts 166 5.2.2.2.1 Copper 166 5.2.2.2.2 Multicomponent Coupled Catalytic Cycles 169 5.3 Ligand-modified Catalvsis 170 5.3.1 Porphyrin Catalysis 171 5.3.2 Schiff Bases 172 5321 Industrial Considerations 175 533 Nitrogen-based Ligands 176 5.3.4 Other Ligand Systems 180 5.3.41 N-Hete yclic Carbenes (NHCs)180 5.3.4.2 5.4 ions and Outlook References 6 Dioxygen Binding and Activation:Reactive Inte ediates 187 Andrew S.Borovi Paul Zinn and Matthew K.Zart 6.1 ntroduction 18. 6.1.1 An Example:Cytochromes P450 188 6.1.1.1 Mechanism 188 6.1.1.2 The Role of the Secondary Coordination Sphere in Catalysis 190 6.12 Effective O2 Binders and Activators in Biology 191 6121 Accessibility 191 6122 Secondary Coordination Sphere 191 61)2 Flow of Electrons and Protons 192 6.12.4 Lessons from Nature 192 6.2 Dioxygen Binders 192 6.21 192 e moglobins 102 6.22 Synthet nalogs 9 6.22.1 Hemoglobin Models 195 6.2.2.2 Hemerythrin Models 196 6.2.2.3 Synthetic #-Peroxo Diiron Complexes 197 6.2.2. Structurally Characterized u-Peroxo Diiron Complexes 198 6.2.2.5 Monomeric Nonheme Iron-Dioxygen Adducts 200 6.2.2.6 Models for Hemocyanin 202 6227 Monomeric Coppe er-Dioxygen Adducts 204 63 6.3.1 Reactive Species with Fe-oxo Motifs 208 6.3.11 Reactive Species from Monomeric Heme Iron-Dioxyger Compl 208 6.3.12 e Species from Monomeric Nonheme Iron-Dioxyger omple 6.3.13 Reactive Intermediates:Nonheme Fe(IV)-oxo Species 212
5.2.2.2 Metal Cocatalysts 166 5.2.2.2.1 Copper 166 5.2.2.2.2 Multicomponent Coupled Catalytic Cycles 169 5.3 Ligand-modified Catalysis 170 5.3.1 Porphyrin Catalysis 171 5.3.2 Schiff Bases 172 5.3.2.1 Industrial Considerations 175 5.3.3 Nitrogen-based Ligands 176 5.3.4 Other Ligand Systems 180 5.3.4.1 N-Heterocyclic Carbenes (NHCs) 180 5.3.4.2 Polyoxometalates (POM) 180 5.4 Conclusions and Outlook 182 References 183 6 Dioxygen Binding and Activation: Reactive Intermediates 187 Andrew S. Borovik, Paul J. Zinn and Matthew K. Zart 6.1 Introduction 187 6.1.1 An Example: Cytochromes P450 188 6.1.1.1 Mechanism 188 6.1.1.2 The Role of the Secondary Coordination Sphere in Catalysis 190 6.1.2 Effective O2 Binders and Activators in Biology 191 6.1.2.1 Accessibility 191 6.1.2.2 Secondary Coordination Sphere 191 6.1.2.3 Flow of Electrons and Protons 192 6.1.2.4 Lessons from Nature 192 6.2 Dioxygen Binders 192 6.2.1 Respiratory Proteins 192 6.2.1.1 Hemoglobins 192 6.2.1.2 Hemerythrin 193 6.2.1.3 Hemocyanins 194 6.2.2 Synthetic Analogs 194 6.2.2.1 Hemoglobin Models 195 6.2.2.2 Hemerythrin Models 196 6.2.2.3 Synthetic -Peroxo Diiron Complexes 197 6.2.2.4 Structurally Characterized -Peroxo Diiron Complexes 198 6.2.2.5 Monomeric Nonheme Iron–Dioxygen Adducts 200 6.2.2.6 Models for Hemocyanin 202 6.2.2.7 Monomeric Copper–Dioxygen Adducts 204 6.3 Reactive Intermediates: Iron and Copper Species 207 6.3.1 Reactive Species with Fe-oxo Motifs 208 6.3.1.1 Reactive Species from Monomeric Heme Iron–Dioxygen Complexes 208 6.3.1.2 Reactive Species from Monomeric Nonheme Iron–Dioxygen Complexes 209 6.3.1.3 Reactive Intermediates: Nonheme Fe(IV)-oxo Species 212 Contents IX
x Contents 6.3.2 Reactive Iron and Copper Intermediates with M(u-O)M Motifs 215 6321 Reactive Intermediates with Cu(III)(u-O)Cu(III)Motifs 215 6.3.2.2 Reactive Intermediates with Cus(u-O),Motifs 217 6.3.2.3 Reactive Intermediates with Felu-O)Fe Motifs 218 221 021 -superoxo Co 222 xygen Complex -Dioxygen Complexes and Their Reactive Intermediates 227 Summary 229 Acknowledgments 229 References 229 Methane Functionalization 235 Brian Conley,William J.Tenn,Ill,Kenneth J.H.Young,Somesh Ganesh, Steve Meier,Jonas Oxgaard,Jason Gonzales,William A.Goddard,Ill., and Roy a Periana 7.1 Methane as a replac ment for Petroleum 235 7.2 Low Temperature is key to economical methane Functionalization 237 Ter eads to Lower Costs 237 ion by CH 238 thane as the Least E ant on the Planet 238 ethane Functional 7.2.5 Requirements of Methane Functionalization Chemistry Influenced by Plant Design 241 7.2.6 Strategy for Methane Hydroxylation Catalyst Design 244 7.3 CH Activation as a Pathway to Economical Methane Functionalization via CH Hydroxylation 245 7.3.1 CH Activation is a Selective,Coordination Reaction 245 732 Comparison of CH Activation to Other Alkane Coordination Reactions 248 7.3.3 Some key challenges and approaches to designing hydroxvlation Catalysts based on the cH activation reaction 253 on 254 Rat of CH Activatio 257 st e of A vents Minimize Catalyst Inh or by Ground State Destabilizat on <60 7.3.32.3 Catalyst Modifications that Minimize Catalyst Inhibition by Ground State Stabilization <64 7.3.32.4 Heterolytic CH Activation with Electron-rich Metal Complexes 267 7.3.3.3 Coupling CH Activation with Functionalization 270 7.3.3.3.1 Functionalization by Formal C-O Reductive Eliminations 270
6.3.2 Reactive Iron and Copper Intermediates with M(-O)2M Motifs 215 6.3.2.1 Reactive Intermediates with Cu(III)(-O)2Cu(III) Motifs 215 6.3.2.2 Reactive Intermediates with Cu3(-O)2 Motifs 217 6.3.2.3 Reactive Intermediates with Fe(-O)2Fe Motifs 218 6.4 Cobalt–Dioxygen Complexes 221 6.4.1 Cobalt-2 -Dioxygen Complexes 221 6.4.2 Dinuclear Cobalt--superoxo Complexes 222 6.5 Manganese–Dioxygen Complexes 225 6.6 Nickel–Dioxygen Complexes and Their Reactive Intermediates 227 6.7 Summary 229 Acknowledgments 229 References 229 7 Methane Functionalization 235 Brian Conley, William J. Tenn, III, Kenneth J.H. Young, Somesh Ganesh, Steve Meier, Jonas Oxgaard, Jason Gonzales, William A. Goddard, III, and Roy A. Periana 7.1 Methane as a Replacement for Petroleum 235 7.2 Low Temperature is Key to Economical Methane Functionalization 237 7.2.1 Lower Temperature Leads to Lower Costs 237 7.2.2 Methane Functionalization by CH Hydroxylation 238 7.2.3 Methane as the Least Expensive Reductant on the Planet 238 7.2.4 Selectivity is the Key to Methane Functionalization by CH Hydroxylation 240 7.2.5 Requirements of Methane Functionalization Chemistry Influenced by Plant Design 241 7.2.6 Strategy for Methane Hydroxylation Catalyst Design 244 7.3 CH Activation as a Pathway to Economical Methane Functionalization via CH Hydroxylation 245 7.3.1 CH Activation is a Selective, Coordination Reaction 245 7.3.2 Comparison of CH Activation to Other Alkane Coordination Reactions 248 7.3.3 Some Key Challenges and Approaches to Designing Hydroxylation Catalysts Based on the CH Activation Reaction 253 7.3.3.1 Stable Catalyst Motifs for CH Activation 254 7.3.3.2 Slow Rates of CH Activation-based Catalysts 257 7.3.3.2.1 Catalyst Inhibition by Ground State Stabilization 257 7.3.3.2.2 Use of Acidic Solvents to Minimize Catalyst Inhibition by Ground State Destabilization 260 7.3.3.2.3 Catalyst Modifications that Minimize Catalyst Inhibition by Ground State Stabilization 264 7.3.3.2.4 Heterolytic CH Activation with Electron-rich Metal Complexes 267 7.3.3.3 Coupling CH Activation with Functionalization 270 7.3.3.3.1 Functionalization by Formal C-O Reductive Eliminations 270 X Contents
Contents XI 7.33.3.2 Functionalization by Oxidative Insertion 273 7.3.33.3 Functionalization by O-Atom Insertion 276 7.4 Conclusions and Perspective for Methane Functionalization 282 References 283 Water Activation:Catalytic Hydrolysis 287 Lisa M Rerreau 8.1 Introduction 287 8.1.1 Water Activation 287 8.1.2 Catalytic Hydrolysis 287 8.2 Water Activation:Coordination Sphere Effects on M-OH2 Acidity mary C tion Environment 288 ng.293 8.2.3 amolecular H-Bonding and Mononuclear Zn-OH Stabilization 29 8.2.4 Structural Effects Derived from M-OH2 Acting as an Intramolecular H-Bond Donor to a Bound Phosphate Ester 298 8.2.5 Ligand Effects on the pK of a Metal-bound Water in Co(III) and Fe(IIl)Complexes 299 8.2.6 Acidity and Water Exchange Properties of Organometallic Aqua 10mg300 8.3 Secondary H-Bonding Effects on Substrate Coordination.Activation and Catalytic hydrolysis Involving phosphate esters 302 8.31 H-Bonding and Phosphate Ester Coordination to a Metal Center 01 8.3.2 H-Bondin and Stochiometric and Catalytic Phosphate Ester Hydrolysis 204 8.4 mary an Future Directions 312 rences 314 9 Carbon Monoxide as a Chemical Feedstock Carbonylation Catalysis 319 Piet W.N.M.van Leeuwen and Zoraida Freixa Introduction 319 9.1.1 Heterogeneous processes 319 9.12 Homogeneous Catalysts 321 Rhodium-catalyzed Hydroformylation 322 9.2.1 Introduction 322 9.2.2 Co as the ligand 323 9.2.3 Phosphites as Ligands 324 9.2.4 osphines 328 9.2.4.1 hin 328 14 kenes
7.3.3.3.2 Functionalization by Oxidative Insertion 273 7.3.3.3.3 Functionalization by O-Atom Insertion 276 7.4 Conclusions and Perspective for Methane Functionalization 282 References 283 8 Water Activation: Catalytic Hydrolysis 287 Lisa M. Berreau 8.1 Introduction 287 8.1.1 Water Activation 287 8.1.2 Catalytic Hydrolysis 287 8.2 Water Activation: Coordination Sphere Effects on M-OH2 Acidity and Structure 288 8.2.1 Primary Coordination Environment 288 8.2.2 Secondary H-Bonding 293 8.2.3 Intramolecular H-Bonding and Mononuclear Zn-OH Stabilization 297 8.2.4 Structural Effects Derived from M-OH2 Acting as an Intramolecular H-Bond Donor to a Bound Phosphate Ester 298 8.2.5 Ligand Effects on the pKa of a Metal-bound Water in Co(III) and Fe(III) Complexes 299 8.2.6 Acidity and Water Exchange Properties of Organometallic Aqua Ions 300 8.3 Secondary H-Bonding Effects on Substrate Coordination, Activation and Catalytic Hydrolysis Involving Phosphate Esters 302 8.3.1 H-Bonding and Phosphate Ester Coordination to a Metal Center 302 8.3.2 H-Bonding and Stochiometric and Catalytic Phosphate Ester Hydrolysis 304 8.4 Summary and Future Directions 312 References 314 9 Carbon Monoxide as a Chemical Feedstock: Carbonylation Catalysis 319 Piet W.N.M. van Leeuwen and Zoraida Freixa 9.1 Introduction 319 9.1.1 Heterogeneous Processes 319 9.1.2 Homogeneous Catalysts 321 9.2 Rhodium-catalyzed Hydroformylation 322 9.2.1 Introduction 322 9.2.2 CO as the Ligand 323 9.2.3 Phosphites as Ligands 324 9.2.4 Arylphosphines as Ligands 328 9.2.4.1 Monophosphines 328 9.2.4.2 Diphosphines 329 9.2.4.2.1 1-Alkenes 333 Contents XI
XⅫ|Contents 9.2.4.2.22-Alkenes335 9.2.4.2.3 Mechanistic Studies 336 9.2.5 Alkylphosphines as Ligands 337 9.2.5.1 osphines 337 Dirhodium Tet ra osphine 338 ation 339 339 anism of the Monsanto Process 340 9.3.3 The Rate-limiting Step 342 9.3.4 Ligand Design 344 9.3.5 Trans-diphosphines in Methanol Carbonylation- Dinuclear Systems?347 9.3.6 Iridium Catalysts 349 9.4 Concluding Remarks 351 References 351 Subiect Index 357
9.2.4.2.2 2-Alkenes 335 9.2.4.2.3 Mechanistic Studies 336 9.2.5 Alkylphosphines as Ligands 337 9.2.5.1 Monophosphines 337 9.2.5.2 Dirhodium Tetraphosphine 338 9.3 Methanol Carbonylation 339 9.3.1 Introduction 339 9.3.2 Mechanism and Side-reactions of the Monsanto Process 340 9.3.3 Oxidative Addition of MeI to Rhodium – The Rate-limiting Step 342 9.3.4 Ligand Design 344 9.3.5 Trans-diphosphines in Methanol Carbonylation – Dinuclear Systems? 347 9.3.6 Iridium Catalysts 349 9.4 Concluding Remarks 351 References 351 Subject Index 357 XII Contents