One-pot stepwise reductive amination reaction by N-coordinate sulfonamido-functionalized Ru(II) complexes in water

Abstract

New complexes of formula [RuCl(p-cymene)(L)] (7-12) were prepared with [RuCl2(p-cymene)](2) and pre-synthesized N-arenesulfonly-o-phenylenediamines (1-6) and characterized using H-1 NMR, C-13 NMR, Fourier transform infrared and UV-visible spectroscopic techniques, and single-crystal X-ray diffraction analysis was performed for one complex (8). Complexes 7-12 were investigated in the reduced imine synthesis reaction (in the presence of HCOONa/HCOOH). The best turnover frequency values were found to be 100 h(-1) for 1 and 99 h(-1) for 6 in the transfer hydrogenative reductive amination reaction of 4-methoxyaniline and 3,4,5-trimethoxybenzaldehyde. The most important feature of this reaction is that it is an environmental friendly procedure because of being conducted in an aqueous environment. That no organic solvent is used allows one to say that this reaction represents green chemistry.