Theoretical, DNA/BSA Binding, Molecular Docking and In Vitro Cytotoxicity Studies of Homoleptic Metal(II) Complexes Derived from 2‐Formylpyridine‐Based Ligands

Abstract

A new class of homoleptic metal(II) complexes of general formula [M(L1–4)2]2Cl in which L1=1‐([1,1′‐biphenyl]‐4‐yl)‐N‐(2‐((‐pyridin‐2‐ylmethylene)amino)ethyl)methanimine, L2=1‐([1,1′‐biphenyl]‐4‐yl)‐N‐(2‐((‐pyridin‐2‐ylmethylene)amino)phenyl)methanimine, L3=1‐([1,1′‐biphenyl]‐4‐yl)‐N‐(2‐((‐pyridin‐2‐ylmethylene)amino)‐4‐nitrophenyl)methanimine and L4=4‐(([1,1′‐biphenyl]‐4‐ylmethylene)amino)‐3‐((−pyridin‐2‐ylmethylene)amino)benzophenone, and M=Ni(II) (1–4), Cu(II) (5–8) and Zn(II) (9–12) have been synthesized and characterized. The IR spectra reveal the involvement of azomethine and 2‐formylpyridine ring nitrogen atoms in chelation. The UV‐Vis and EPR spectral studies envisage distorted octahedral geometry around metal(II) ion. All the complexes were stable for 72 h in biologically relevant solutions, and copper(II) complexes were reduced to Cu+ center in the presence of ascorbic acid solution. The binding studies of complexes with calf thymus DNA (CT‐DNA) indicate groove mode of binding, and the complexes 3, 7 and 11 containing the 4‐nitrophenyl substituent exhibit the highest binding affinity than the other complexes. Furthermore, the spectral studies also revealed the interaction of complexes with BSA through static mechanism. In vitro cytotoxicity activity of the complexes was screened against human lung adenocarcinoma (A549) and breast adenocarcinoma (MCF‐7) cancerous, and normal murine fibrosarcoma (L929) cell lines. The molecular docking studies of the homoleptic metal(II) complexes show hydrophobic, π–π, σ–π and hydrogen bonding interactions with EGFR/VEGFR2 kinase receptors.