Photochemistry and C-H Activation Reactivity of TpMe2IrH2(COE) in Benzene Solution.

Research on the activation of C-H bonds is very actively pursued and stable transition metal compounds which can accomplish such activation are now known for a number of systems. The process leading to the formation of such compounds usually involves either the photochemical or thermal generation of high-energy, electronically and coordinatively unsaturated intermediates capable of inserting into the C-H bond of an alkane or arene. The work described here centers on the photolysis, in solution, of a tris(pyrazolyl) borate complex of iridium, i.e., TpMe2IrH2(COE) (TpMe2 = tris(3,5-dimethylpyrazolyl)borate, COE = cis-cyclo-octene), 1. Photolysis of this complex, in benzene in the presence of P(OMe)3, produces the stable hydrido phenyl iridium(III) complex 2 (eq. 1). This complex was characterised in solution by one- and two-dimensional multinuclear NMR spectroscopy.