Nickel and cobalt complexes of benzoic acid (2-hydroxy-benzylidene)-hydrazide ligand: synthesis, structure and comparative in vitro evaluations of biological perspectives

Abstract

Reactions of tridentate chelating hydrazone Schiff bases benzoic acid (2-hydroxyl-benzylidene)-hydrazide (H₂L) (1) obtained from salicylaldehyde and benzhydrazide with [NiCl₂(PPh₃)₂] and [CoCl₂(PPh₃)₂] afforded respective metal hydrazone complexes of the composition [Ni(L)(PPh₃)] (2) and [Co1(L)₂]₂[Co2(H₂O)₄(OPPh₃)₂] (3). The molecular structure of both complexes 2 and 3 determined by single crystal X-ray diffraction revealed that complex 2 is neutral in charge with distorted square planar geometry. However, complex 3 was found to have distorted octahedral geometry. All of the synthesised compounds 1–3 were studied by interaction with calf thymus DNA (CT DNA) and bovine serum albumin (BSA). In addition in vitro free radical scavenging and cytotoxic potential of all the synthesised compounds were also investigated.