Dorothy H. Gibson of the University of Louisville (Kentucky) is supported by the Inorganic, Bioinorganic, and Organometallic Chemistry program for research on cyclical catalytic systems that reduce carbon dioxide to organic compounds that contain one or two carbon atoms (together with oxygen and hydrogen atoms). A long-term benefit of such research would be development of efficient cyclical catalytic systems that could produce fuels from the ubiquitous 'green-house gas,' carbon dioxide. One main aim of the research is to identify effective catalysts and catalytic cycles. A second main goal will be to increase understanding of how such cyclical catalysts function. A main thrust of the research is to explore the causes and effects of catalytic reactions in which there are changes in the number of coordination sites (on metal atoms) spanned by particular ligands ('variable denticity'). Both electrochemical and photochemical techniques will be employed.
Target reduction products include formic acid, formaldehyde and methanol, and also glyoxylic acid and glycolic acid. Catalytic species being investigated include a number of rhenium, rhodium and ruthenium complexes that contain both bipyridine molecules (as 'electronic reservoirs') and other ligands that have the ability to change (reversibly) between bidentate and terdentate configurations. Preliminary results have identified several promising catalytic systems. A number of examples of putative reaction intermediates have been prepared and characterized.
