Structural investigation of discrete solvent protonated vanadium and other transition metal complexes of N'-[(E)-(3-ethoxy-2-hydroxyphenyl)methylidene]benzohydrazide, synthetic, spectroscopic and cytotoxicity studies

Abstract

A new ligand 3-ethoxysalicylaldehyde benzoic hydrazone (H2ESB) and its copper(II), nickel(II), cobalt(II), zinc(II), and dioxidovanadium(V) complexes have been synthesized and characterized by elemental analysis, IR, UV–Vis and EPR studies. Copper(II) complex (2) contains 2,2′-bipyridine as a coligand. Aroyl hydrazone and its copper and vanadium complexes were characterised by single crystal XRD. The vanadium compound crystallized in triclinic space group P1- and copper compound in orthorhombic space group P212121. The solvent molecule DMF protonates to form ammonium ion in vanadium complex which neutralises the charge on the vanadium ion. Both complexes copper and vanadium show distorted square pyramidal geometry. From EPR results, spin Hamiltonian and bonding parameters were calculated. The g values in copper complexes indicate the presence of the unpaired electron in the dx2−y2 orbital. In vitro cytotoxicity studies of aroylhydrazone and its complexes showed that copper, cobalt and vanadium complexes are more cytotoxic than hydrazone and other complexes against Dalton’s lymphoma ascites cells (DLA).