Synthesis, Spectral, Electrochemical and Biological Studies on Co(II), Ni(II), Cu(II) and Zn(II) Complexes Derived from 4-(2-Aminoethyl)benzene-1,2-diol and Terephthalaldehyde

Abstract

A novel Schiff base ligand (L) has been synthesized using 4-(2-aminoethyl)benzene-1,2-diol (dopamine) and terephthalaldehyde. This hexadentate ligand has been used to synthesize cobalt(II), nickel(II), copper(II) and zinc(II) complexes with stoichiometry (1:2). Several techniques were used to characterize the compounds, including elemental analysis, molar conductivity, magnetic moment, mass spectra, cyclic voltammetry, SEM and powder XRD. Co(II), Ni(II), Cu(II) and Zn(II) have octahedral geometry based on physico-chemical characterization studies. Using cyclic voltammetry (CV), the redox properties of the metal complexes were extensively studied. These metal complexes were studied by SEM analysis to determine their surface morphology Solvatochromic behaviours of synthesized compounds have been assessed using UV-vis absorption spectroscopy. By disc diffusion method, the ligand and its metal(II) complexes were tested for antibacterial activity against two Gram-positive bacteria, two Gram-negative bacteria and one fungus. Using the HRBC membrane stabilization method, the Schiff base ligand and its copper(II) complex were evaluated for their anti-inflammatory properties. In vitro anticancer activity of the copper(II) complex was investigated by MTT assay on the human breast cancer cell line (MCF-7). According to the results, the copper(II) complex inhibits breast cell growth better than the Schiff base. Using an α-amylase inhibitory assay method, the ligand and its copper(II) complex were also tested for their antidiabetic effects in vitro. In comparison with the Schiff base ligand, the copper(II) complex showed the best activity.