Synthesis, characterization, electron paramagnetic property and catalytic amidation of binuclear ruthenium(III) complexes

A series of new binuclear ruthenium(III) complexes [ Ru2Cl4(EPh3)4(L)] (E = P or As) were successfully synthesized from 1:2 mol ratio of bi-nucleating ligand precursors (L1H2-L3H2) and [RuCl3(EPh3)3] in benzene for 6 h. The complexes were characterized by elemental analysis, FT-IR, UV–vis, magnetic susceptibility measurements and EPR spectroscopy methods. Rhombic distortion (gx ≠ gy ≠ gz) around the ruthenium ion was confirmed by EPR spectra in liquid nitrogen temperature. Catalytic activity of the facile one pot amidation reaction has been developed. The complex [Ru2Cl4(AsPh3)4(L1)](4) was found to possess excellent conversion up to 100 % of amide in toluene with the presence of hydroxylamine hydrochloride and NaHCO3 at 110 °C in 2 h. The effect of time, temperature, solvents and different catalytic loading experiments was also investigated.