This award in the Inorganic, Bioinorganic, and Organometallic Chemistry Program supports research by Dr. Joseph S. Merola of the Chemistry Department, Virginia Polytechnic Institute, on oxidation addition reactions of various organic substrates to iridium phosphine complexes. The substrates involve E-H bonds, where E = H,B,C,N,O. The reaction chemistry of the series of E-Ir-H compounds thus generated will be investigated, especially with respect to the insertion of unsaturated molecules into the E-Ir and H-Ir bonds. Thus, fundamental processes occurring at the metal center in chemistry related to hydrogenation, catalytic hydroboration, C-H bond activation, hydroamination, and hydroalkoxlylation will be studied. Anionic groups on the iridium will be varied in order to promote the catalytic activity of these systems. Some of the reactions will be carried out in aqueous solution. %%% Oxidation addition reactions play an important role in both catalytic and stoichiometric reaction chemistry of organometallic compounds. The long range goal of this project is to develop catalyst systems for the addition of E-H bonds to unsaturated organic compounds. This could have important industrial implications but since the reaction chemistry of these potentially significant processes is not well known, fundamental advances are also anticipated.