Synthesis of molybdenum and tungsten complexes and their application in olefin epoxidation

Abstract

This thesis comprises the synthesis of serious of molybdenum and tungsten complexes and their application in olefin epoxidation reaction. Chapter 1 provides a brief historic overview of the development of molybdenum and tungsten organometallic complexes and their application in olefin epoxidation. Chapter 2 describe the synthesis of Mo(0) and W(0) bis(diphenylphosphanyl)amine (PNP) complexes. The Mo complexes can be applied as active and selective olefin epoxidation catalysts. In chapter 3, the synthesis and reactivity of Mo(0) and W(0) N-heterocyclic carbene (NHC) complexes has been studied. The stability of metal- NHC bonds under the oxidative condition has been studied. Chapter 4 describe the synthesis of a series of NHC complexes with the formula CpMo(CO)2(NHC)X (X=Br, Cl or BF4). The stability of metal-NHC ligand bonds in these compounds under oxidative conditions has been investigated. The thermally stable Mo(VI) dioxo NHC complex has been isolated by the oxidation of the ionic complexes.