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