Synthesis, characterization, molecular modeling and antioxidant activity of (1E,5E)-1,5-bis(1-(pyridin-2-yl)ethylidene)carbonohydrazide (H2APC) and its zinc(II), cadmium(II) and mercury(II) complexes

Abstract

A new series of Zn(II), Cd(II) and Hg(II) complexes of (1E,5E)-1,5-bis(1-(pyridin-2-yl)ethylidene)carbonohydrazide (H2APC) have been prepared and characterized by elemental analyses, spectral (IR, UV–visible, mass and 1H NMR) as well as magnetic and thermal measurements. The data revealed that the ligand acts a monobasic hexadentate, neutral tri- and monodentate in Zn(II), Cd(II) and Hg(II) complexes, respectively. An octahedral geometry is proposed for Zn(II) complex, a trigonal bi-pyramid for Cd(II) complex and a tetrahedral one for Hg(II) complex. The bond length, bond angle, HOMO, LUMO and charges on the atoms have been calculated to confirm the geometry of the ligand and the investigated complexes using material studio program. Kinetic parameters were determined for each thermal degradation stage of some complexes using Coats–Redfern and Horowitz–Metzger methods. The antioxidant, anti-hemolytic, and cytotoxic activities of the compounds have been screened. H2APC showed moderate antioxidant activity using ABTS and DPPH methods. With respect to erythrocyte hemolysis and in vitro Ehrlich ascites assay, H2APC exhibited the potent antioxidative activity followed by Cd(II) and Zn(II) complexes while Hg(II) complex showed very weak activity.