Synthesis, characterization, theoretical calculations and enzymatic activities of novel diimine-dioxime ligand and its homodinuclear Cu(II) complex

Abstract

A novel ligand [2-(biphenyl-4-yl)-2-(2-(1-(biphenyl-4-yl)-2-(hydroxyimino) ethylideneamino)ethylimino)acetaldehyde oxime] (BPHEO) and its homodinuclear Cu(II) complex [Cu2(L) (H2O) (phen)](ClO4)2 were prepared starting from biphenyl and characterized by different physical techniques. Elemental analysis, ICP-OES, FT-IR, UV–vis molar conductivity, magnetic moment measurements and thermal analyses studies were used for the characterization of the complexes. The free ligand was also characterized by 1H and 13C NMR spectra. Elemental analyses, stoichiometric and spectroscopic data of the metal complex indicated that the metal:ligand ratio of homodinuclear Cu(II) complex was found to be 2:1. The structural and vibrational spectroscopic data of the BPHEO and its homodinuclear Cu(II) complex were calculated and confirmed by DFT method. Chemical shifts (1H and 13C NMR) of the ligand were also calculated using the gauge-independent atomic orbital (GIAO) method. Furthermore the synthesized complex was tested as catalyst for the catalytic oxidation of 3,5-di-tert-butylcatechol to 3,5-di-tert-butylquinone at aerobic medium (catecholase-like activity) and disproportionation of hydrogen peroxide to the water and molecular oxygen in the presence of 1-methylimidazole (catalase-like activity). It was found that the complex showed moderate catalytic activity and suitable as a catalyst for the selected enzymatic reactions.