Coordination chemistry of nickel(II), copper(II), and cobalt(II) with MN₄ core-containing two novel vic-dioximes ligands. Synthesis, spectroscopy and redox properties

Two new vic-dioxime, N-(4-amino-1-benzyl piperidine)-anti-phenylglyoxime (L₁H₂) and N-(4-amino-1-benzyl piperidine)-anti-glyoxime (L₂H₂) were prepared by the reaction of anti-phenylchloroglyoxime and anti-monochloroglyoxime with 4-amino-1-benzyl piperidine in absolute THF at -15°C. Mononuclear nickel(II), copper(II), and cobalt(II) complexes have a metal-ligand ratio of 1:2 in which the ligands coordinate through the two nitrogen atoms as do most vic-dioximes. The ligands and their Co(II), Cu(II), and Ni(II) complexes were characterized by elemental analyses, FT-IR, UV-vis, ¹H-NMR and ¹³C-NMR, magnetic susceptibility measurements, electrical conductivity measurements and cyclic voltammetry. The electrical conductivity of Ni(II), Co(II), and Cu(II) metal complexes were measured using Four-Point Probe analysis. The electrochemical behavior of the Ni(II), Co(II), and Cu(II) complexes were investigated by cyclic voltammetry in DMSO.