Photochemical features of intermolecular C-H bond activation

The photophysical and photochemical properties of the C-H activating (eta(5)-C5H5)Rh(CO)(2), (eta(5)-C5Me5)Rh(CO2), (eta(5)-C5H5)Ir(CO)(2) and (HBPz(3)*)Rh(CO)(2) (Pz* = 3,5-dimethylpyrazolyl) complexes in room-temperature hydrocarbon solutions are compared and contrasted. Recent quantitative measurements of the solution photochemistry and kinetic analyses of the reaction pathways are discussed. The data reveal that the C-H and Si-H activation reactions occur via similar photochemical routes, whereas the ligand photosubstitution reaction proceeds by a different pathway. Several key mechanistic features of the light-induced intermolecular C-H bond activation process are identified. (C) 1998 Elsevier Science S.A.