New Cu (II) and Zn (II) metal chelates derived from azo‐Schiff bases: Synthesis, DNA/BSA binding, anticancer activity and molecular docking studies

Abstract

In this study, new Cu (II) and Zn (II) chelates (3–6) of 3‐/or 4‐ethyl and azo chromophore groups (NN) containing Schiff base ligands (2‐{(E)‐[(4‐ethylphenyl)imino]methyl}‐4‐[(E)‐phenyldiazenyl]phenol, HL1 (1) and 2‐{(E)‐[(3‐ethylphenyl)imino]methyl}‐4‐[(E)‐phenyldiazenyl]phenol, HL2 (2) were prepared and characterized by the analytical and spectroscopic methods. Crystal structures of chelates 3, 4 and 6 were determined by single‐crystal X‐ray diffraction studies. The ligands behaved as bidentates, coordinating through the nitrogen atom of the azomethine group (CHN) and the oxygen atom of the α‐hydroxyl group (OH). The metal:ligand ratio in the prepared copper (II) and zinc (II) chelates was found to be 1:2 by analytical and spectral analysis. The bands in the infrared spectra of the metal chelates in the region of 522–504 cm−1 and 467–455 cm−1 are attributed to ν(MO) and ν(MN) vibrations, respectively. When the DNA binding activities of the compounds were examined, it was determined that compound 4 had the highest binding constant. Fluorescence and viscosity data showed that the compounds interact with DNA through minor grove binding mode. Furthermore, anticancer properties of the compounds were investigated. Ligand 2 was found to be highly effective against the HepG2 cell with an IC50 of 0.31 μM. In addition, structural analysis, frontier molecular orbitals, molecular electrostatic potential maps, Hirshfeld surface analysis of the synthesized compounds using computational chemistry methods and anticancer activity studies were carried out by molecular docking.