Preparation of monocarbonyl ruthenium complexes bearing bidentate nitrogen and phosphine ligands and their catalytic activity in carbonyl compound reduction.

Monocarbonyl complexes [RuCl(CO)(PR)(NN)] (R = Cy, NN = en 1, ampy 2; R = iPr; NN = en 3) have been prepared in a one pot reaction from [RuCl(CO)(dmf)(PPh)], PR and the NN ligand in CHCl. Treatment of [Ru(OAc)(CO)(PPh)] with NN ligands in methanol gives the cationic derivatives [Ru(OAc)(CO)(PPh)(NN)]OAc (NN = en 4, ampy 5) in which one acetate acts as a bidentate ligand, whereas the other is not coordinated. Diphosphine complexes [RuCl(CO)(PP)(PPh)] (PP = dppb 6, dppf 7, (R)-BINAP 8, (R,S)-Josiphos 9 and (R,R)-Skewphos 10) have been obtained starting from [RuCl(CO)(dmf)(PPh)] and the PP ligand in CHCl or toluene at reflux. The reaction of [Ru(OAc)(CO)(PPh)] with PP in CHCl or toluene affords the fluxional acetate derivatives [Ru(OAc)(CO)(PP)] (PP = dppb 11, dppf 12, (R)-BINAP 13, and (R,R)-Skewphos 14). The cationic diphosphine complexes [RuCl(CO)(PP)(en)]Cl (PP = dppb 15, dppf 16) are prepared from [RuCl(CO)(dmf)(PPh)], PP and en in CHCl or, alternatively, from [RuCl(CO)] or the 6, 7 derivatives. Similarly, [Ru(OAc)(CO)(PP)(NN)]OAc (PP = dppb, NN = en 17, ampy 18; PP = dppf, NN = en 19, ampy 20) are isolated starting from [Ru(OAc)(CO)(PPh)], PP and NN ligands or from 11, 12. The derivatives [Ru(OAc)(CO)(PP)] show a fluxional behavior in solution as the result of the flexible coordination of acetate ligands. These complexes are found to be active in the transfer hydrogenation and hydrogenation of ketones and aldehydes, including furfural derivatives, at an S/C up to 10 000 and a TOF up to 18 000 h.