Pyridyl based ruthenium(II) catalyst precursors and their dihydride analogues as the catalytically active species for the transfer hydrogenation of ketones

The catalytic activity of a series of ruthenium(II) complexes of the type cis-[RuCl2(PPh3)2(L)] (L = pyridyl based bifunctional ligand) for the transfer hydrogenation of various aromatic ketones using 2-propanol as the hydrogen source, is described. Isolated and spectroscopically characterized ruthenium(II)dihydride complexes have been proposed as the catalytically active species.