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The present study deals with the synthesis of (E)‐N'‐(2,5‐dimethoxybenzylidene)‐2‐hydroxybenzohydrazide, a hydrazone Schiff base ligand (HY) and its metal complexes [Co(HY)2, Ni(HY)2, Zn(HY)2].2H2O. The structure of the synthesized ligand was characterized by physico‐chemical analytical and spectral techniques. The electrochemical behavior of HY and its complexes were investigated by cyclic voltammetry. Infrared spectral data suggested that HY acts as a tridentate ligand with ONO as the donor atoms. Molar conductivity data showed that all the complexes were non‐electrolytic in nature and octahedral geometry of the complexes was confirmed by UV‐visible spectrum. TGA studies of the complexes gave a clear idea about the coordination sphere and the process of degradation. Further, HY and its complexes were screened for their in vitro antioxidant, antibacterial and anticancer activities. Among the synthesized complexes, Ni(II) and Zn(II) metal complexes showed prominent antioxidant activity investigated through their scavenging effect on DPPH radical, anticancer activity against MCF‐7 and HeLa cancer cells. The molecular docking into P53 cancer mutant protein (PDB ID: 5AB9) was done for the optimization of the investigated compounds as potential cancer cell inhibitors. The observed data infer that all the complexes show promising antimicrobial activity against all of the tested bacterial and fungal species compared to the parent ligand HY. [ABSTRACT FROM AUTHOR]

Condensation of 3‐pyridine carboxaldehyde with 2/3‐thienyl dipyrromethanes in presence of acid catalyst gives 5‐(3′‐pyridyl)‐10,15,20‐tri(2/3‐thienyl)porphyrins (S1a and S2a) due to scrambling along with the expected trans‐porphyrins. The corresponding copper(II) and zinc(II) porphyrins were also synthesized. Moreover, to study their biological properties their cationic derivatives were obtained. All the complexes were characterized by UV‐Vis, fluorescence, NMR spectroscopy, mass spectrometry and cyclic voltammetry. The cationic porphyrins bind with DNA non‐intercalatively; show singlet oxygen mediated photocleavage; phototoxic to A549 lung cancer cells through apoptotic pathway. We explored the DNA interaction and human epithelial lung cancer cell toxicity of few mono‐cationic pyridinium porphyrins bearing thienyl substituents obtained via scrambling. All the complexes bind with DNA non‐intercalatively and show singlet oxygen mediated photocleavage. The intrinsic binding constants, Kb of these porphyrins to DNA was found to be in the order of 105 M‐1. Fluorescence imaging studies show that the porphyrins are phototoxic to A549 lung cancer cells through apoptotic pathway. [ABSTRACT FROM AUTHOR]