Fast Transfer Hydrogenation(TH) in Aerobic Condition and Oxidation of Alcohols withN-Methylmorpholine-N-oxide Catalyzed by Ru(II) Ligated with Chalcogenated Pyridines and PPh3

The transfer hydrogenation (TH) of aldehydes / ketones (at mmol level), using propan-2-ol as a H-source is complete within 15 min when catalyzed by 0.1 mol% of [Ru(L)(PPh3)Cl-2]] (1-4;L=L1-L4;L1/L2=(E)-2-(phenylthio/seleno)-N-(pyridin-2-ylmethyene)ethan-amine,L3/L4=2-(phenylthio/seleno)-N-(pyridin-2-ylmethyl)ethan- amine). The1-4were prepared by treating [Ru(PPh3)(3)Cl-2] withL1-L4respectively.TheL1-L4and1-4were characterized by(1)H,C-13{H-1} and(77)Se{H-1} NMR spectra. Single crystal structures of1-4determined by X-ray diffraction revealed distorted octahedral geometry of Ru in each complex and bond lengths (angstrom) as: Ru-S, 2.3441(1) and 2.335(3) and Ru-Se, 2.4497(2) and 2.4518(4). Each of1-4 (0.1 mol%) is almost equally efficient as catalyst for TH and oxidation of alcohols withN-methylmorpholine-N-oxide (NMO). The optimum amount of oxidant NMO was found 3 mmol for 1 mmol of alcohol. In ambient conditions both the catalytic reactions by the four complexes appear to be homogeneous. The scope of substrates for both the reactions is reported.