This project, funded in the Inorganic, Bioinorganic and Organo- metallic Chemistry Program, provides for continuation of studies on bimetallic complexes that are encapsulated in a macrocyclic ligand such that one metal ion is six coordinate and serves as an electron reservoir and the other metal ion is four coordinate and can coordinate dioxygen or an oxo ligand. The ultimate goal is to find systems that can cause four- electron reduction of dioxygen and to use products of such reactions to catalytically oxidize organic substrates. Initial studies have suggested that five and six membered chelate rings formed by complexation of the macrocyclic ligand donors to the metal ions lead to high strain and prevent the formation of complexes with the desired stereochemistry. In this phase of the investigation new ligand designs that will result in the formation of seven membered rings will be tested with the expectation that steric effects will be reduced and the desired product stereochemistry will be realized. The proposed ligands will also allow for the incorporation of asymmetry and thus will allow for possible asymmetric oxygenations. %%% Whereas many biological oxidants use molecular oxygen effectively for oxidation of organic molecules scientists have been much less successful in performing similar reactions in the laboratory. Success in this endeavour could be of significant industrial consequence as molecular oxygen is a readily available and inexpensive reagent and biological oxidations are typically highly selective. Studies such as those planned by Professor Bosnich are designed to provide the fundamental information that will ultimately be required to develop the necessary technology to use molecular oxygen for selective oxidations on an industrial scale.
