DNA interaction, antimicrobial and molecular docking studies of biologically interesting Schiff base complexes incorporating 4‐formyl‐N,N‐dimethylaniline and propylenediamine

Abstract

Four new transition metal complexes incorporating a Schiff base ligand derived from propylenediamine and 4‐formyl‐N,N‐dimethylaniline have been synthesized using transition metal salts. The characterization of the newly formed complexes was done from physicochemical parameters and using various techniques like 1H NMR, 13C NMR, IR, UV, electron paramagnetic resonance and mass spectroscopies, powder X‐ray diffraction and magnetic susceptibility. All the complexes were found to be monomeric in nature with square planar geometry. X‐ray powder diffraction illustrates that the complexes have a crystalline nature. The interaction of metal complexes with calf thymus DNA was investigated using UV–visible absorption, viscosity measurements, cyclic voltammetry, emission spectroscopy and docking analysis. The results indicate that the Cu(II), Co(II), Ni(II) and Zn(II) complexes interact with DNA by intercalative binding mode with optimum intrinsic binding constants of 4.3 × 104, 3.9 × 104, 4.7 × 104 and 3.7 × 104 M−1, respectively. These DNA binding results were rationalized using molecular docking in which the docked structures indicate that the metal complexes fit well into the A‐T rich region of target DNA through intercalation. The metal complexes exhibit an effective cleavage with pUC19 DNA by an oxidative cleavage mechanism. The synthesized ligand and the complexes were tested for their in vitro antimicrobial activity. The complexes show enhanced antifungal and antibacterial activities compared to the free ligand.