This Presidential Young Investigator Award from the Inorganic, Bioinorganic and Organometallic Chemistry Program will support research in biologically relevant inorganic chemistry. The emphasis of the project will be the elucidation of the role of metal ions in important biological transformations. Of particular interest is the participation of transition metal ions in the terminal steps of the reduction of dioxygen by cytochrome oxidase and the evolution of oxygen by the photosynthetic apparatus. Small molecule analogs of the metal centers of these and other metalloproteins, especially manganese-containing proteins, will be synthesized and characterized. The general strategy to be taken will involve the design and synthesis of organic ligands, preparation and purification of their complexes with transition metals, and thorough characterization of such systems by a variety of structural, magnetic, and spectroscopic techniques. In addition to the systems mentioned above, others of interest include the magnetically-coupled siroheme and iron-sulfur cluster in sulfite reductase, and the participation of nickel in hydrogenase and methanogenesis activity. Finally, the role of low valent vanadium in catalyzing the conversion of dinitrogen to ammonia and hydrazxine will be explored. Comparison of the spectroscopic and chemical properties of the model compounds is expected to yield valuable insight into the detailed workings of the modeled biological systems.
