Copper(II), nickel(II), zinc(II) and cadmium(II) complexes of 1,2,4-triazole based Schiff base ligand: Synthesis, comparative spectroscopic, thermal, biological and molecular docking studies

Herein, a Schiff base ligand, 9-(((5-mercapto-4H-1,2,4-triazole-4-yl)imino)methyl)-anthracene and its metal complexes with copper(II), nickel(II), zinc(II) and cadmium(II) ions have been synthesized and systematically characterized by certain analytical and multispectral studies. Fourier transform infrared, proton nuclear magnetic resonance, microanalysis, mass spectra, electronic spectra, magnetic moment, powder X-ray diffraction analysis, thermogravimetric-differential thermogravimetric analyses and electron spin resonance spectroscopy techniques have explicated the structure of the complexes. The copper complexes showed square planar geometry whereas other complexes are in an octahedral geometry. Metal complexes exhibited a remarkable fluorescence response. The electrochemical property, i.e., oxidation-reduction potential of copper complexes was enlightened by cyclic voltammetry. The activation thermodynamic parameters for the decomposition steps of complexes were documented using the Coats-Redfern method. Adverse antimicrobial activities of titled compounds have been studied against different microbes; in addition, 1,1-diphenyl-2-picrylhydrazyl assay was also used to evaluate the antioxidant activity of these compounds. Molecular docking was exercised to vaticinate the binding of the ligand with receptors of crystal structures of Escherichia coli, Bacillus subtilis and Candida albicans.