This award in the Inorganic, Bioinorganic, and Organometallic Chemistry Program supports research on multielectron oxidation-reduction processes by Daniel G. Nocera of the Chemistry Department, Michigan State University. The long-term goal is to develop detailed understanding of the mechanism of multielectron processes in order to enable rational design of reactions such as atom transfer and reductive elimination. Reactions of metal-localized excited states of quadruply bonded metal-metal complexes will be investigated. Tungsten and molybdenum complexes and mixed-valence binuclear rhodium fluorophosphine complexes will be synthesized for use in the studies. The photoexcited intermediates generated will be characterized by picosecond and nanosecond time-resolved excited state spectroscopy. Solar photoconversion has great potential as an efficient means of promoting complex chemical transformations which require movement of more than one electron. Such reactions occur in natural systems during nitrogen fixation, but chemists have yet to understand the reaction details well enough to be able to design reactions in which sunlight rather than heat is used beneficially. Much of what is known involves one-electron processes. This project will provide additional information on reactions involving bond breaking and bond making, which are fundamental to chemical transformations and generally involve multiple electrons.