This project in the Inorganic, Bioinorganic and Organometallic Chemistry Program deals with the synthesis and study of compounds which are designed to model the active site of blue copper proteins. These important proteins have a variety of functions, including participation in electron-transfer chains and the transport and activation of molecular oxygen. The target protein sites are the reduced and oxidized sites of the blue proteins which participate in electron transfer chains and the sequentially oxidized binuclear units in hemocyanins and tyrosinases which respectively bind dioxygen for transport and activate dioxygen to accomplish the ring hydroxylation of aromatic substrates. Previous work on ligand design in this project has afforded redox-stable Cu(II) aliphatic thiolates and Cu(I) and Cu(II) complexes having pseudotetrahedral coordination by biologically realistic ligands, such as imidazoles, thiolates and thioethers. The technology for synthesizing and elaborating polyimidazole ligands will be further developed with the aim of preparing good synthetic approximations of these target sites. The relationship of electronic structure to molecular structure will be probed by a combination of crystallographic, electronic spectral, electrochemical, epr, molecular orbital, and photoelectron spectroscopic and single crystal spin-echo studies. General questions regarding the epr properties of approximately tetrahedral Cu(II) and the nature of azide-to-Cu(II) LMCT will be probed by oriented single crystal spectroscopic studies of Cu(II) doped into isostructural Zn(II) lattices.
