Synthetic Inorganic Models for Biological Activation and Reduction of Nitrous Oxide and Carbon Dioxide

Synthetic inorganic models for biological activation and reduction of nitrous oxide and carbon dioxide is presented in this thesis. Chapter one discusses reduction and conversion of nitrous oxide and carbon dioxide gases to control their impacts on the earth atmosphere by nitrous oxide reductase and CO dehydrogenase. In this chapter we also discuss the important role of bimetallic cooperative effect in both multimetallic nitrous oxide and reductase CO dehydrogenase enzymes in the activation and reduction of N2O and CO2, respectively. Chapter two examines the small-molecule activation by Hillhouse’s carbene-supported [Cu2(µ-S)] complex as a model of CuZ site to add further insight into possible roles of tetranuclearity in CuZ and its effect on unsupported sulfide ligand in the active site. Chapter three investigates a tunable bimetallic effect on product selectivity in catalytic CO2 reduction by using N-heterocyclic carbene-ligated Cu complexes. Introducing a bimetallic effect with analogous Cu−Fe, Cu−W, and Cu−Mo catalysts produces mixtures of formate and CO. Within a series of isosteric catalysts, the selectivity of CO versus formate can be controlled by tuning the electronic nature of the Cu/M (M= Fe, W, Mo) pairing. Chapter four discusses catalytic hydroboration of ketones and aldehydes by readily available copper carbene complex, (IPr)CuOtBu, at very low catalyst loadings (0.1 mol%), in some cases with turnover frequencies exceeding 6000 h-1. The hydroboration of ketones and aldehydes occurs selectively in the presence of other reducible functional groups including alkenes, nitriles, esters, and alkyl chlorides.