The reaction of bromoalkanes (R-Br; (3), R=CnH2n+1. n=4 (a), 8 (b), 12 (c),18 (d)) and bromobenzyl derivatives (R'-Br; (4), R'=CH2C6H2(CH3)(3)-2,4,6 (a); CH2C6H(CH3)(4)-2,3,5,6 (b); CH2C6(CH3)(5) (c)) with 1H-imidazo[4,5-f][1,10]-phenanthroline (IP)(L-2) gave the corresponding 1-R-imidazo[4,5-f][1,10]-phenanthroline (IPR)(L3a-d) and 1-R'-imidazo[4,5-f][1,10]-phenanthroline(IPR')(L4a-c) ligands, respectively. Treatment of L3a-d and L4a-d with [Ru(p-cymene)Cl-2](2) led to the formation of [Ru(p-cymene)(IPR)Cl]Cl (RuL3a-d) and [Ru(p-cymene)(IPR')Cl]Cl (RuL4a-c). New ruthenium(II) complexes RuL3a-d and RuL4a-c were characterized by elemental analysis, FTIR, UV-visible and NMR spectroscopy. In order to understand effects of these changes on the N-substituent of imidazol on IP and how they translate to catalytic activity, these new RuL2, RuL3a-d and RuL4a-c were applied in the transfer hydrogenation of ketones by 2-propanol in presence of potassium hydroxide. The activities of the catalysts were monitored by NMR and GC analysis. (C) 2013 Elsevier Ltd. All rights reserved.