Hydride complexes of ruthenium derived from the heterolytic activation of dihydrogen by amidophosphine complexes

{The reaction of [NPNH]Ru(eta(3):eta(2)-Cyclooctadienyl) (1) (where [NPNH] = [ PhNHSiMe2CH2P(Ph)CH2SiMe2NPh}), an organometallic mono-amide complex of ruthenium(II), with hydrogen gas (1-4 atm) generates three ruthenium hydride species: [NPNH]RuH (2), [NPNH2]RuH2(C7H8) (3) and [NPNH2]RuH2 (4). All of these complexes result from hydrogenation of the cyclooctadienyl group; complexes 3 and 4 also undergo conversion of the amido linkage into a ruthenium hydride and an amine. Complexes 2 and 3 have been characterized both in solution by NMR spectroscopy and in the solid state by X-ray Diffraction and Infrared Spectroscopy. While 4 was fully characterized in solution by NMR spectroscopy, attempts to recrystallize this material yielded 2; the reaction of 2 with H, does not produce 4. The starting complex I acts as a catalyst precursor for the hydrogenation of imines such as benzylidene aniline; however, none of the isolated hydride species 2, 3 or 4 were active as catalyst precursors.