This project, funded by the Inorganic, Bioinorganic and Organo- metallic Chemistry Program, deals with the mechanistic based development of catalysts for alkane carbonylation and the reverse process, aldehyde decarbonylation. Several approaches to the development of catalytic systems will be studied including novel radical-based photochemical and thermal systems, photochemically activated trans-carbonylchloro- bis(trimethylphosphine)rhodium(I), and other thermally activated compounds of rhodium and ruthenium. Both experi- mental and theoretical approaches to catalyst design will be utilized. %%% Selective functionalization of hydrocarbons under mild conditions remains as one of the most significant, but elusive, goals of modern chemistry. The technological implications of selective, and energy-efficient reactions of hydrocarbons are enormous. Recent discoveries by organo- metallic chemists have indicated that certain transition metal complexes will react with hydrocarbons under mild conditions. This project will attempt to extend these earlier studies to generate catalytic cycles in which metallated hydrocarbons react with carbon monoxide to produce aldehydes, which can serve as precursors to a wide variety of other types of compounds.