Synthesis, characterization and biological studies on NiII and CuII complexes of two novel α,β-unsaturated 1,3-diketones related to curcuminoids

Abstract

Microwave assisted synthesis of two novel α,β-unsaturated 1,3-diketones, their mononuclear NiII and CuII complexes, characterization, results on DNA binding activities, short term in vitro and in vivo antitumor activities were reported. The ligands are structurally related to curcuminoids and exhibited significant antitumor activity against Dalton’s lymphoma ascites cells. The ligands were found to be existing in their enolic form and metal complexes have 1:2 metal ligand stoichiometry evidenced by electronic, IR, 1H NMR, 13C NMR and FAB mass spectral data. The DNA binding properties of ligand and metal complexes were studied by absorption titrations and by viscosity measurements with calf thymus DNA. The intrinsic binding constants of copper(II) complexes are slightly higher than complexes of same metals reported in the literature. Interaction of copper(II) complexes were found to be higher than that of nickel(II) complexes and free ligands. The copper(II) complexes of the ligands were found to be more effective towards Dalton’s lymphoma ascites cells in both in vitro and in vivo studies.