The synthesis, spectroscopic and voltametric studies of new metal complexes containing three different vic-dioximes

The synthesis, spectroscopic, and redox properties of some metal complexes with three novel vic-dioxime ligands, N-(1-(2-aminoethyl)piperazine)- phenylglyoxime (L1H2), N-(1-(2-aminoethyl)piperazine)-glyoxime (L2H2), and N,N′-bis(1-(2-aminoethyl)piperazine)-glyoxime (L3H2)], prepared from different glyoxime and 1-(2-aminoethyl)piperazine are reported. The structure of these vic-dioximes have been determined as the anti-form according to 1H NMR, 13C NMR, and FT-IR data. The metal to ligand ratios of Co(II), Ni(II), and Cu(II) complexes were found to be 1:2. The Cu(II) complexes of these ligands are proposed to be square planar and Ni(II) complexes of these ligands are proposed to be square planar or octahedral, while the Co(II) complexes are proposed to be octahedral with water molecules as axial ligands. Ni(II), Co(II), and Cu(II) metal complexes are non-electrolytes as shown by their molar conductivities (ΛM) in DMF (dimethyl formamide) at 10-3 M. The structure of ligands and their complexes is proposed from elemental analysis, FT-IR, UV-VIS, 1H NMR, 13C NMR, magnetic susceptibility measurements, and molar conductivity measurements. The cyclic voltammetric measurements of the mononuclear complexes provide an understanding of the electrochemical behaviour of the reduced or oxidized species in DMSO solution.