Photochemistry of M(PPsub 3)Hsub2 (M = Ru, Os; PPsub3 = P(CHsub2CHsub2PPhsub2)): Preparative, NMR and time-resolved studies

Photochemical elimination of dihydrogen is a key route to carbon-hydrogen bond activation, particularly by half-sandwich rhodium, osmium and iridium compounds. The photochemical method is able to obtain kinetic data by laser flash photolysis. Studies of complexes of the type RU(Rsub2PCHsub2CHsub2PRsub2)sub2Hsub2 (R = Me, Et, Ph, Csub2Fsub5), showed that each undergoes dihydrogen photodissociation, yielding 16-electron Ru(Rsub2PCHsub2CHsub2Prsub2)sub2 fragrments, characterized by a multiband UV/vis spectra. The photochemistry of RU(PPsub3)Hsub2 and Os(PPsub3)Hsub2 by preparative and in situ NMR is explored.