SYNTHESIS AND CHARACTERIZATION OF RUTHENIUM(II) COMPLEXES CONTAINING CHIRAL BIS(FERROCENYL)-P-3 OR BIS(FERROCENYL)-P2S LIGANDS - ASYMMETRICTRANSFER HYDROGENATION OF ACETOPHENONE

A number of new chiral bis(ferrocenyl)-triphosphine ligands have been synthesized by the reaction of cyclohexylphosphine with different chir al ferrocenyl aminophosphines in hot acetic acid. The thioether ligand {(S)-1-[(R)-2-(diphenylphosphino)ferrocenyl]ethyl} sulfide has been s imilarly prepared by the reaction of (S)-1-[(R)-2-(diphenylphosphino)f errocenyl]ethyl acetate with either (S)-1-[(R)-2-(diphenylphosphino)fe rrocenyl]ethyl mercaptan or (S)-1-[(R)-2-(diphenylphosphino)ferrocenyl ]ethyl mercaptan sodium salt. All the above reactions proceed with ret ention of configuration on the side-chain stereocenters of the startin g materials. Monomeric Ru(II) complexes containing either chloride or acetonitrile coligands have been prepared with all the chiral tridenta te ligands. Both the new ligands and the ruthenium complexes have been characterized by multinuclear NMR spectroscopy. The structure of [(S) -(R)-Pigiphos]RuCl2 . 2CH(2)Cl(2) ((S)-(R)-Pigiphos = nylphosphino)fer rocenyl]ethyl}cyclohexylphosphine) has been determined by X-ray diffra ction. The asymmetric transfer hydrogenation of acetophenone catalyzed by various Ru(II) bis(ferrocenyl) tridentate complexes in propan-2-ol is also reported.