Synthesis, characterization, biological activity, DFT, molecular docking and ADME studies of metal (II) complexes of a bidentate Schiff’s base (E)-4-chloro-2-((2-hydroxy-3-methoxybenzylidene)amino)benzoic acid
Manisha, Amit Kumar, Mohammad Abid, Saiema Ahmedi, Nikhat Manzoor, Raquib Alam, Pallavi Jain
Abstract
A new Schiff base ligand (E)-4-chloro-2-((2-hydroxy-3-methoxybenzylidene)amino)benzoicacid (CHMB) was synthesized through condensation reaction of Ortho-Vanillin and 2-amino-4-chloro-benzoic acid in 1:1 ratio. CHMB-Mn(II) chloride complex (C1), CHMB-Mn(II) acetate complex (C2), CHMB-Cu(II) acetate complex (C3), CHMB-Zn(II) chloride complex (C4), CHMB-Zn(II) acetate complex (C5), were similarly synthesized using a 2:1 ratio. The synthesized compounds were characterized using various techniques, that is, FT-IR,1H-NMR, 13C-NMR, mass spectrometry, UV-Visible spectroscopy, and thermogravimetric analysis. FT-IR analysis confirmed the bidentate nature of the ligand, indicating bond formation with metal ions through the nitrogen atom of the azomethine group and the oxygen atom. Spectroscopic methods including FT-IR, UV-Visible, and mass spectroscopy verified that all complexes displayed an octahedral geometry. Adsorption dissociation metabolism and excretion (ADME) studies predicted the drug-likeness probability for all synthesized compounds. The molecular docking studies examined the interaction between compounds and bacterial/fungal proteins. The geometrical optimization and DFT calculation were performed using Gaussian 09 W software. All the complexes were evaluated for antimicrobial activities against five bacterial and three fungal strains. Anticancer screening of the ligand and complexes against human cancer cell line (A549) was examined using MTT assay. CHMB-Zn(II) acetate complex (C5) possessed highest antimicrobial activity (with lowest MIC values), whereas CHMB-Cu(II) acetate complex (C3) exhibited highest anticancer activity (with lowest IC50 = 44.78 μg).