The interaction of [Rh(COD)Cl]2 with two equivalents of (S)-N,NX-biswo-( diphenylphosphino) benzylidenexpropane-1, 2-diamine [(S)-1] or (S)-N, N'-bis [o-(diphenylphosphino) benzylxpropane-1, 2-diamine [(S)-2] in benzene/methanol mixture and then precipitation by the addition of a solution of NH4PF6 in water afforded cationic rhodium (I) complexes [Rh(S)-MeP2N2] [PF6] and [Rh(S)-MeP2 (NH)2] [PF6] in good yield, respectively. Complexes [Rh(R,R)-C6P2N2] [PF6] and [Rh(R,R)-C6P2(NH)2] [PF6] were also prepared by an analogous manner. All these rhodium complexes have been characterized by analytical and spectroscopic methods and their asymmetric catalytic properties for enantioselective transfer hydrogenation of acetophenone have been tested. [Rh(R,R)-C6P2(NH)2] [PF6] was used as an excellent catalyst precursor for enantioselective transfer reduction of acetophenone in 2-propanol, leading to 2-phenylathanol in 97% yield and in 91% ee after 7 h at 83℃.

The condensation of (S)-propane-1, 2-diamine with two equivalents of o- (diphenylphosphino) benzaldehyde gives (S)-N, N'-bis[o-(diphenylphosphino) benzylidenexpropane-1, 2-diaminew [(S)-1] ligand. The reduction of (S)-1 with excess NaBH4 is carried out in refluxing ethanol to afford corresponding (S)-N, N'-bis [o-(diphenylphosphino) benzylxpropane-1, 2-diamine [(S)-2]. The interaction of trans-RuCl2(DMSO)4 with one equivalent of (S)-1 or (S)-2 in refluxing toluene gives (S)-3 or (S)-4 in good yield, respectively. (S)-1, (S)-2, (S)-3 and (S)-4 have been fully characterized by analytical and spectroscopic methods. The structure of (R)-3 has been also established by an X-ray diffraction study. Catalytic studies showed that (S)-4 as an excellent catalyst precursor for the asymmetric transfer hydrogenation of acetophenone with 90% yield and up to 91% enantiomeric excess.

Water-soluble and air-stable triruthenium carbonyl cluster Ru3 CO.9 TPPMS.3 TPPMSssodium diphenylphosphi-nobenzene-m-sulphonate. was used as catalyst precursor to hydrogenated acrylic acid in good yield. The cluster also catalyzed the hydroformylation of propylene with syngas in water, the main product is n-butyraldehyde; side-products are iso-butyraldehyde and a small amount of 1-butyl and isobutyl alcohols. At 1208C and propylene, CO and H2 partial pressures of 0.7 MPa, 2.0 MPa and 2.0MPa, respectively, catalytic turnover of 61.2 mol productsrmol cluster h and product n:i ratio of 15.9 were obtained. For ethylene hydroformylation, the main product is propanal; side-products are 3-pentanone, 1-propanol and 2-methyl-pent-2-en-1-al. The catalyst was characterized before and after the reaction by IR and. X-ray photoelectron spectroscopy and the results were discussed as related to the possible catalytic active species. q1999 Elsevier Science B.V. All rights reserved.

The condensation of o-(diphenylphosphino)benzaldehyde and various chiral diamine gives a series of diimino-diphosphine tetradentate ligands, which are reduced with excess NaBH4 in refluxing ethanol to afford the corresponding diaminodiphosphine ligands in good yield. The reactivity of these ligands toward trans-RuCl2(DMSO)4 and [Rh(COD)Cl]2 had been investigated and a number of chiral Ru(II) and Rh(I) complexes with the PNNP-type ligands were synthesized and characterized by microanalysis and IR, NMR spectroscopic methods. The chiral Ru(II) and Rh(I) complexes have proved to be excellent catalyst precursors for the asymmetric transfer hydrogenation of aromatic ketones, leading to optically active alcohols in up to 97% ee. Chirality 12: 383-388, 2000.

The chiral Ru cluster-based catalyst systems generated in situ from Ru3(CO)12 and chiral iiminodiphosphine tetradentate ligands effected asymmetric transfer hydrogenation of propiophenone in 2-propanol, leading to 1-phenyl-1-propanol in 94% yield and with 96% ee.