Heteroleptic ruthenium(II) complexes of 2-(2-pyridyl)benzimidazoles: A study of catalytic efficiency towards transfer hydrogenation of acetophenone

Abstract

Six ruthenium(II) complexes ([RuCl2(p-cymene)(L1-6)], SD1-6, (L1-6: bidentate pyridyl-benzimidazole ligands)) were synthesized from [RuCl2(p-cymene)](2) dimer and bidentate pyridyl-benzimidazole ligands. The compounds were characterized by elemental analysis, IR, UV-Vis, NMR and X-ray diffraction. The synthesized Ru(II) complexes (SDI-6) were tested as catalysts for the catalytic transfer hydrogenation (CH) of acetophenone to secondary alcohols in the presence of KOH using 2-propanol as a hydrogen source at 82 degrees C. All complexes were active catalysts for TM of acetophenone with good yields under mild conditions (after 15 min, yields of up to 91%). (C) 2014 Elsevier Ltd. All rights reserved.