The role of N-heterocyclic carbene substituents on ruthenium(II) complexes inthe catalytic transfer hydrogenation of acetophenone

Abstract

The novel ruthenium(II) complexes [RuCl2(NHC)(p-cymene)],3a{e, containing 1-alkyl-3-benzylimidazol-2-ylidene ligands were prepared. All synthesized compounds were characterized by NMR spectroscopy and elementalanalyses. Ru(II)-NHC complexes were tested as catalysts for the transfer hydrogenation of acetophenone, showing modestto high activity in this reaction. The results revealed that efficiencies depend on the substituents of the benzene ring ofthe benzyl on the N atom of the NHC ring.