Preparation of a series of Ru(II) complexes with N-heterocyclic carbene ligands for the catalytic transfer hydrogenation of aromatic ketones.

The reaction of RuCl(2)(p-cymene with Ag-N-heterocyclic carbene (NHC) complexes yields a series of [(p-cymene)Ru(NHC)] complexes (2a-f). All synthesised compounds were characterized by elemental analysis, NMR spectroscopy and the molecular structure of 2a was determined by X-ray crystallography. All complexes have been tested as catalysts for the transfer hydrogenation of aromatic ketones, showing excellent activity in this reaction.