This award in the Inorganic, Bioinorganic, and Organometallic Chemistry Program supports research on sulfur, oxygen, and nitrogen transfer reactions by Dr. Robert G. Bergman of the Department of Chemistry, University of California-Berkeley. Transition metal complexes capable of transferring heteroatoms, such as sulfur, oxygen, and alkylated nitrogen, between organic molecules and metal centers will be studied. Initial work will focus on organotantalum complexes which remove these atoms and groups from three-membered organic ring compounds, creating hydrocarbons and new metal complexes with heteroatom-metal multiple bonds. After this initial phase, the project will define the mechanism of these reactions in preparation for identifying other metal complexes which can run these reactions in reverse catalytically, thus generating complexes which can convert alkenes into species such as epoxides, thiiranes and aziridines. The transfer of heteroatoms such as sulfur, oxygen, and nitrogen between organic molecules and transition metal centers is a fundamental chemical process in organic and biological enzyme chemistry. The results should lead to the design of reactions useful in organic synthesis in the chemical and pharmaceutical industries, and to methods for removal of sulfur, oxygen, and nitrogen from fuels, thus reducing production of environmentally harmful sulfur and nitrogen oxides from this source.