Synthesis, spectroscopic characterization, electrochemical behaviour and antibacterial activity of Ru(III) complexes of 2-[(4-N,N′-dimethylaminophenylimino)-methyl]-4-halophenol

The reaction of the chelating Schiff base ligands 2-[(4-N,N′-dimethylaminophenylimino)-methyl]-4-X-phenol with [Ru(Cl) 3(EPh 3) 3]; (E = P or As); (X = Cl, Br or I) in the benzene afforded new stable ruthenium complexes of the general formula [Ru(Cl) 2(EPh 3) 2(L)] (L = anion of bidentate Schiff bases). The newly synthesized complexes were characterized using molar conductivity, spectral (UV–vis, FT-IR and EPR) and electrochemical studies. The molar conductance measurements proved that all these complexes are non-electrolytes. All complexes show strong d–d transition in the visible region. The coordination of imine nitrogen and phenolic oxygen of ligands to ruthenium metal was confirmed with the change in the IR stretching frequency values. The EPR spectral data showed that the complexes are paramagnetic with one unpaired electrons. The redox behaviour of the complexes have been investigated by the cyclic voltammetric technique. All the complexes display an irreversible reduction (Ru III/Ru II) in the range of −0.826 to −0.971 V. In view of the biological activity, the ligands and the complexes were observed that all the complexes showed moderate activity. Also the antibacterial activity of the ligand increased on chelation with metal ion.