THE PHOTOCHEMISTRY OR RHENIUM HYDRIDES. A FLASH PHOTOLYTIC INVESTIGATION OF THE TRANSIENTS IN THE PHOTOCHEMISTRY OF TRIS(DIMETHYLPHENYLPHOSPHINE)PENTAHYDRIDORHENIUM(V)

Article abstract of DOI:10.1016/S0022-328X(00)98632-7

The photochemistry of ReH5P3, (P<*>PMe2Ph) has been investigated by laser and conventional flash photolysis.The first species observed in laser flash photolysis of the rhenium complex in saturated hydrocarbons has been assigned as an heptacoordinated 16-electron complex, ReH5P2, which is found to react with P at the diffusion-controlled rate.However, for photolysis in benzene such species is replaced by another metastable product, ReH5P2(C6H6), which is proposed to be a η²-C6H6 complex.At 10^-5 M Re, isomerization and possibly elimination of hydrogen in subsequent unimolecular steps can precede dimerization, which has also been observed.The observed transient transformations have been correlated with previous observations during continuous photolysis, including coordination of simple olefins and H/D exchange of aenes.Kinetic measurements reveal that the transient ReH5P2 forms a dimetallic species by reaction with ReH5P3 and not with another (unsaturated) transient.