Synthesis of novel heterobimetallic copper(i) hydrazone Schiff base complexes: A comparative study on the effect of heterocyclic hydrazides towards interaction with DNA/protein, free radical scavenging and cytotoxicity

Abstract

Two new copper(I) hydrazone complexes have been synthesised from bivalent copper precursor [CuCl₂(PPh₃)₂] and ferrocene containing bidentate hydrazone ligands HL¹ (1) or HL² (2). Based on the elemental analyses and spectroscopic data, the complexes are best formulated as [CuL¹(PPh₃)₂] (3) and [CuL²(PPh₃)₂] (4) of the monovalent copper ion. Solid state structures of ligand 2 and its corresponding complex 4 were also determined. The DNA/albumin interactions of all the synthesised compounds were investigated using absorption, emission and synchronous fluorescence studies. Further, antioxidant properties of all the compounds have also been checked against ABTS, O₂⁻ and OH radicals. Additionally, the in vitro cytotoxic activity of compounds 1–4 was assessed using tumour (HeLa, A431) and non-tumour (NIH 3T3) cell lines.