SYNTHESIS AND CHARACTERIZATION OF RUTHENIUM COMPLEXES OF 1,8-BIS(DIPHENYLPHOSPHINOMETHYL)NAPHTHALENE (BDNA) AND THEIR CATALYTIC-HYDROGENATION REACTIONS TO ALPHA,BETA-UNSATURATED ALDEHYDES

A new ligand BDNA [1,8-bis(diphenylphosphinomethyl)naphthalene] and th ree ruthenium complexes containing the new ligand, Ru2Cl4(BDNA)(2) 1, RuHCl(CO)(PPh3)(BDNA) 2, and RuH2(CO)(PPh3)(BDNA) 3, have been synthes ized. Their compositions and structures were characterized by P-31{H-1 }-NMR, H-1-NMR, and elemental analysis. Molecular structure of 3 was a lso confirmed by single-crystal X-ray diffraction. The crystal belonge d to the triclinic crystal system, P (1) over bar space group, a = 10. 7450(7), b = 12.7100(7), c = 18.1390(13) Angstrom, alpha = 89.558(6), beta = 83.117(2), gamma = 80.859(5)degrees, V = 2428.0(3) Angstrom(3), and Z = 2. The hydrogenation results of citral and cinnamaldehyde rev ealed that complex 2 had good catalytic activity and complex 3 had the high selectivity for the hydrogenation of C=O bond in alpha,beta-unsa turated aldehydes to form the corresponding allylic alcohols. In the p resence of complex 3, very high selectivities of 99.5 and 95.1% were o btained for the hydrogenation of the carbonyl group in citral and cinn amaldehyde, respectively. (C) 1998 Elsevier Science S.A. All rights re served.