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