Synthesis, Spectral Characterization and Electrochemical Investigations of Mononuclear Cu (II), Ni (II) and Co (II) Metal Complexes Containing Different New vic-dioxime Groups

Abstract

Three new vic-dioxime: N -(2-methyl-2-butylamine)-anti-p-tolylglyoxime (L₁H₂), N -(4-amino-2,2,6,6-tetramethylpiperidine)-anti-p-tolylglyoxime (L₂H₂) and N,N′-(4-amino-2,2,6,6-tetramethylpiperidine)-anti-glyoxime (L₃H₂) were prepared by the reaction of anti-p-tolylchloroglyoxime and anti-dichloroglyoxime with 2-methyl-2-butylamine and 4-amino-2,2,6,6-tetramethylpiperidine in absolute THF at −15°C. Mononuclear metal complexes with a metal-ligand ratio of 1:2 were prepared using Cu(II), Ni(II) and Co(II) salts. FT-IR spectra show that the ligands act in a tetradentate manner and coordinates N₄ donor groups of ligands to Cu(II), Ni(II) and Co(II) ions. The Cu(II) complexes of these ligands are proposed to be square-planar; the Ni(II) and Co(II) complexes are proposed to be octahedral with two water molecules as axial ligands. The ligands and their metal complexes were characterized by elemental analyses, Ft-IR, UV-Vis, ¹H and ¹³C-NMR spectra, magnetic susceptibility measurements and cyclic voltammetry. The electrochemical behavior of the Ni(II), Co(II) and Cu(II) complexes was investigated by cyclic voltammetry in DMSO as well.

Keywords:

• electrochemical investigations
• H-bonding
• metal complexes
• oximes

This work was supported by the Scientific Research Council of Harran University (Project No: HUBAK-744).

Notes

∗Shoulder.

^a Cathodic peak potential for reduction, anodic peak potential for oxidation for irreversible processes.

^b E _1/2 = E_pc+ E_pa/2

^c Δ E _p = E _{pc –} E _pa at 0.100 V s^{− 1} scan rate.