RUTHENIUM DIPHOSPHINE COMPLEXES FOR CATALYSIS - A GENERAL-SYNTHESIS AND DIRECT COMPARISONS WITH RHODIUM COMPLEXES

A method for the preparation of diphosphineruthenium complexes from a range of diphosphine precursors is described. The stable products, of general formula P2Ru(allyl)acac (P = phosphine ligand), do not catalys e the hydrogenation of alkenes but can easily be converted into cataly tically active species by reaction with trimethylsilyl trifluoromethan esulfonate. The chemistry involved in this transformation is discussed . Catalysis of the hydrogenation of a range of alkenes, and direct com parison with related rhodium reductions, is described. Some mechanisti c insights are gained through additions of D-2 to alkenes and parallel hydrogenations on deuterated solvent, supporting the intervention of conventional dihydride and alkyl hydride intermediates which undergo e xchange with solvent at both stages.