This award in the Inorganic, Bioinorganic, and Organometallic Program supports research on photoinitiated electron transfer reactions by Dr. Karen J. Brewer of the Chemistry Department, Virginia Polytechnic Institute. Trimetallic complexes which covalently couple two light-absorbing metal centers to a central metal section through polypyridyl bridging ligands will be synthesized. In these complexes, low lying unoccupied orbitals on the ligand are capable of accepting electrons and mediating the electron transfer between metal sites. The photophysical and electrochemical properties of these complexes will be studied in order to find the optimal conditions for promoting electron build-up, as well as to understand the details of multi-electron transfer. Many important reactions in nature, such as the reduction of carbon dioxide and nitrogen fixation, require many electrons. The goal of this project is to investigate a method for promoting multi-electron transfer reactions. Metal complexes which can each contribute electrons will be linked together in large molecules. Light will be used to drive electrons between metal centers so that a number of electrons can be available for reaction. Although it is concerned with only a part of the process, this study is expected to provide basic information related to the development of solar-powered devices which could be used to promote a variety of chemical reactions.
