Preparation, characterization, and catalytic properties of (triphenylphosphine)ruthenium complexes bearing N,O,N′-tridentate ligands

Preparation and characterization of (triphenylphosphine)ruthenium complexes bearing N,O,N′-tridentate ligands, [(L1)RuCl(PPh3)2](BF4) (L1 = 2-[(2-pyridylmethoxy)methyl]pyridine), 1), [(L2)RuCl(PPh3)2](BF4) (L2 = 8-(2-pyridylmethoxy)quinoline, 2) and [(L3)RuCl2(PPh3)] (L3 = 2-[(2-pyridylmethoxy)methyl]quinoline, 3) are described. Complexes 1–3 have been characterized by NMR and elemental analyses. Molecular structures of 2 and 3 have been determined by X-ray crystallography. Both compounds exhibit the octahedral geometry. L2 adopts the facial configuration in 2 while L3 is in a mer-arrangement in 3. Complexes 1–3 have proven to be able to catalyze the transfer hydrogenation of several ketones to alcohols in the presence of KOH and 2-propanol at refluxing, among which complex 3 was found to be the most active.