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

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, O-2(-) 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.