HEXARUTHENIUM CARBIDO CARBONYL METHYL CLUSTER [PPN][RU6C(CO)16(CH3)] AS CATALYST PRECURSOR FOR HYDROGENATION OF OLEFINS - SYNTHESES AND STRUCTURES OF UNSATURATED AND SATURATED HEXARUTHENIUM HYDRIDO CLUSTERS [PPN][RU6C(CO)15H] AND [PPN][RU6C(CO)16H]

Cluster [PPN][Ru6C(CO)16(CH 3)] (2) has been found to be catalytic active for the hydrogenation and isomerization of olefins at 60-degrees-C after an induction period. Reaction of 2 or [PPN][Ru6C(CO)15(C3H5)] with dihydrogen at 130-degrees-C gives an unsaturated hydrido cluster [PPN][RU6C(CO)15H] (6), which behaves as the catalyst at ambient temperature. The structure of 6 has a carbon-centered octahedral geometry of ruthenium atoms which is surrounded by fifteen carbonyl ligands, two terminal ones for each ruthenium atom and three bridging ones, and a bridging hydrido ligand. Treatment of 6 with carbon monoxide yields a saturated hydrido cluster [PPN][RU6C(CO)16H] (5), which is also prepared by protonation of [PPN]2[RU6C(CO)16]. X-ray analysis of 5 shows the cluster anion is disordered between two sites in the ratio of 8 to 2. The major one contains a carbon centered octahedron of six ruthenium atoms with two terminal carbonyl ligands for each ruthenium atom, with four bridging carbonyl ligands, and a terminal hydrido ligand.