PREPARATION AND CHARACTERIZATION OF 92-ELECTRON HEXAHYDRIDOHEXARUTHENIUM CARBONYL CLUSTER COMPLEXES - THEIR POTENTIAL SIGNIFICANCE IN HOMOGENEOUS CATALYTIC-HYDROGENATION

The 48-electron complex [Ru3(mu-H)(mu3-eta2-ampy) (CO)9] (1; ampy = 2- amino-6-methylpyridinate) reacts with molecular hydrogen (110-degrees- C, 1 atm) to give the 92-electron hexanuclear hexahydrido derivative [ Ru6-(mu-H)6(mu3-eta2-ampy)2(CO)14] (2). This hexanuclear compound unde rgoes CO substitution instead of ligand addition when treated with P(p -tolyl)3 to give the complex [RU6(mu-H)6(mu3-eta2-ampy)2{P(p-tolyl)3}2 (CO)12] (3), which has been characterized by X-ray diffraction methods . Compound 2 is an efficient catalyst precursor for the homogeneous hy drogenation of diphenylacetylene to cisstilbene under mild conditions (50-degrees-C, 1 atm).