Supramolecular Assemblies of Copper(Ii) Complexes with Hydrazone Based Ligand: Biomimetic Synthesis, Hirshfeld Surface Analysis, Biological Activity and Quntum Chemical Study

Abstract

Three new supramolecular assemblies of copper(II) hydrazone based complexes viz., [Cu(L)(CH 3 COO)]∙H 2 O 1 , [Cu(L)(4,4’-bipy)(NO 3 )] 2 and [Cu(L)(NO 3 )(H 2 O)]∙H 2 O 3 have been synthesized by biomimetic synthesis strategy using tridentate hydrazone based ligand (HL = 2-hydroxy-benzoic acid (phenyl-pyridine-2-yl-methylene)-hydrazide). These synthesized  hydrazone based complexes were characterized by elemental analysis, UV-visible and FTIR spectroscopic techniques. Molecular structures were determined from single-crystal X-ray crystallography. All complexes form hydrogen-bonded assemblies of different dimensionalities and architectures. Other non-covalent interactions like CH π, π π and lp π interactions also provide stabilities of supramolecular architectures. These non-covalent interactions were also explored by Hirshfeld analysis. The magnetic values at room temperature of complexes 1 and 2 are slightly less than spin-only value. The magnetic susceptibility of 3 is investigated at low temperature and its magnetic behavior can be described as involving non-interacting S = ½ Cu 2+ ions. The X-band epr spectra of all complexes show hyperfine structures and zero-field splitting which are indicative for the triplet state due to dipole-dipole (pseudo dipole) interaction in the polycrystalline state. Quantum chemical calculations (DFT) were performed to explore the electronic and spectral features of complexes. Finally these complexes were substituted for biological activity measurements. All complexes ( 1-3 ) exhibited the feasible superoxide dismutase (SOD) activity and antiproliferative property. Findings of biological activity show that structural diversity have significant effect on the SOD and antiproliferative activity.

Keywords: Copper(II) complexesSupramolecular structures Antiproliferative activity SOD activity Hirshfeld surface analysis