The Inorganic, Bioinorganic and Organometallic Chemistry Program supports basic research in Organometallic Photochemistry. This research supported by the program is aimed at future efforts in solar conversion and photocatalysis. Pulsed laser flash photolysis (FP), through which kinetically-labile species in solution implicated in important thermal reactions of substituted metal carbonyls and silenes may be generated, will be employed to probe intermediate reaction steps. Rates of reaction will be investigated by both UV/visible and IR spectroscopy and as a function of variable high pressure (FP/HP) to 200 MPa. The FP/IR technique, which employs a line-tuneable IR diode laser analyzing beam, is under continuing development in the project. It will afford high-resolution carbonyl stretching spectra through which bonding properties in metal carbonyl transients can be probed. Successful demonstration of FP/HP which affords volumes of activation will be particularly useful in the elucidation of mechanisms of reaction for photochemically-generated metal carbonyl intermediates where corresponding thermal reactions take place via interchange pathways. The energetics of specific reactions of photoproduced coordinatively-unsaturated metal carbonyls with halogenated solvents to form X-to-metal coordinate bonds, and with aliphatic and aromatic hydrocarbon solvents to form three-center C-H-to-metal bonds, will be probed. FP/IR will also be employed to investigate trans-cis isomerization in substituted coordinatively-unsaturated metal carbonyls and will be extended also to investigations of "trapping" reactions of silenes in which the Si-H stretching frequencies will be monitored.
