Bis(carboranes) in catalysis : from chelation to metalation

Abstract

Chapter 1 is an overview of the chemistry of carboranes and their reactivity with particular focus on metalation and use in catalysis. The chemistry of bis(carboranes) is also discussed in detail. A full scope of thesis is also included. Chapter 2 describes the development of synthetic routes using bis(o-carborane) as a chelating ligand to a ruthenium centre. Novel compounds are characterised and suitable species are tested as catalysts in Diels-Alder cycloaddition reactions. Chapter 3 expands on the synthesis of new catalysts exploring substitution reactions on the cages of bis(o-carborane). Octamethyl-bis(o-carborane) is synthesised and used as a ligand to a metal centre. One product is tested as a catalyst in Diels-Alder cycloaddition reactions. Chapter 4 discusses the displacement of arene ligands from arene-ruthenium derivatives of bis(o-carborane) using phosphine and phosphite ligands. This resulted in an experimental and computational study of a novel isomerisation process. The new characteristics and reactivity of these compounds are discussed and suitable compounds are tested as catalysts in Diels-Alder cycloaddition reactions. Chapter 5 introduces bis(m-carborane) as a different type of ligand to a metal centre. The metalation of bis(m-carborane) is discussed using different metal fragments. Chapter 6 outlines the experimental procedures for all new compounds discussed, including synthesis and analysis. Appendix A explores the use of bis(o-carborane) as a ligand on Au(III) metal centres with a comprehensive study of novel compounds. Appendix B summarises the crystallographic data for all compounds studied by XRD in this thesis.