Mechanisms in iron, nickel, and manganese, catalysis with small molecule oxidants

Oxidation plays a vital role in the metabolism of living organisms, manifested in a finely organized set of enzymes and proteins to selectively oxidize substrates in a controlled fashion. Biochemical oxidation has inspired many scientists to model the processes found in living organisms to synthetic reactions, so called bio-mimics. However, the bio-mimetic complexes developed are often quite different structurally to their biological counterparts due to limitations in the synthesis of large molecular structures to surround the active centers, and especially second co-ordination sphere effects. In this thesis, mechanistic studies of iron, nickel and manganese complexes are described with the oxidants H2O2, NaOCl and O2. The aim of this thesis is to give insight into the complex nature of the transition metal centers and the ligands around it under catalytic conditions. Here, we show that the efficiency of the catalysts in oxidation is critically dependent on the concentration of water, and selectivity, and yields of products can be increased using additives such as acetic acid. These mechanistic studies performed focused on speciation of the complexes formed under reaction conditions using a battery of spectroscopic, theoretical and electrochemical methods. These studies resulted in the characterization of reactive intermediates that oxidize substrates, which in turn gives insight into the reaction mechanisms, and finally ultimately opens doors to achieving high catalytic yields.