Development of Bis(amidophenyl)amine Redox-active Ligands for Multi-electron Catalysis by Transition Metals Restricted; Files Only

Liu, Dan (Fall 2020)

Permanent URL: https://etd.library.emory.edu/concern/etds/5d86p135d?locale=en
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Abstract

The development of transition metal catalysts for multi-electron chemical transformations have been investigated intensively in the past decades. Although significant progress has been made in applying precious metals such as rhodium, ruthenium or palladium for these transformations, the application of earth-abundant metals for catalyzing multi-electron chemical transformations are less well-studied.

In chapter 2 of this dissertation, the design, synthesis, characterization, and application of a series of dinuclear NiII complexes for catalytic oxidative dehydrogenation of hydrazones to form diazo compounds as the product will be described. Through modifications in the ligand scaffold, the effect of electronic properties, steric bulk, the presence of weak C-H bond, and the appearance of secondary H bonding donor on the catalytic reactivity of the corresponding NiII complexes were investigated. Chapter 3 reports the design, synthesis, and characterization of the novel 4-coordinated square planar NiII complexes for catalytic aziridinations. Mechanistic studies revealed that a 5-coordinated NiIII complex supported by a ligand radical likely acts as the reactive intermediate during the catalytic process. In Chapter 4, new RuII complexes are designed with easy preparation and purification. These RuII complexes are applied to catalytic C-H amination reactions.

Table of Contents

Chapter 1. Historical Development of Redox-active Ligands and Their Applications in Promoting First-row Transition Metal Catalysis 1

Introduction 1

Redox-active ligands in nature 2

Development of redox-active ligands 4

Dithiolene Ligand 4

Dioxolane Ligand 7

Amidophenolate and Diimine Ligand 9

Applications of first-row transition metal catalysts supported by redox-active ligands in catalysis 15

Metal Carbene chemistry 16

Metal Nitrene chemistry 17

Reference 22

Chapter 2. The Design, Synthesis and Characterization of Nickel Catalysts and Their Corresponding O2 Activation Reactivity 36

Abstract 36

Introduction 38

Results and discussion 40

Ligand synthesis 40

Synthesis of nickel complexes 42

Conclusion 66

Experimental section 68

General considerations 68

Ligand synthesis 70

Synthesis of nickel complexes 74

Catalytic aerobic oxidation procedure 81

Catalytic O-atom transfer reaction procedure 88

Appendix I 89

References 90

Chapter 3. Nitrene Transfer Reactions Catalyzed by a Nickel (II) Complex Incorporated with Redox-Active Ligands 98

Abstract 98

Introduction 99

Ligand synthesis 102

Synthesis of nickel complex 104

Results and discussion 105

Catalytic aziridinations and mechanistic studies 114

Conclusion 122

Experimental section 124

General considerations 124

Ligand synthesis 125

Synthesis of nickel complexes 130

Synthesis and characterization of PhINTs 135

General catalytic aziridination reaction procedure 135

Appendix I 139

Appendix II 140

Appendix III 141

Appendix IV 142

References 143

Chapter 4. The Design and Synthesis of Ruthenium Catalysts for C-H Aminations and Oxygenations 147

Abstract 147

Introduction 148

Ruthenium catalysts for sp3 C-H nitrogenations 149

Ruthenium catalysts for sp2 C-H nitrogenations 150

Ruthenium catalysts for sp3 C-H oxygenations 152

Ruthenium catalysts for sp2 C-H oxygenations 152

Ligand synthesis 155

Synthesis of ruthenium complexes 156

Results and discussion 157

C-H nitrogenation and oxygenations 178

Intramolecular sp3 C-H amination 178

Intramolecular sp2 C-H aminations 180

Intermolecular C-H aminations 182

Intramolecular sp2 C-H hydroxylation 183

Conclusion 184

Experimental section 185

General considerations 185

Ligand synthesis 186

Synthesis of ruthenium complexes 191

General procedures for catalytic reactions 198

Appendix I 200

Reference 201

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