Synthesis, structural and antimicrobial studies of transition metal complexes of a novel Schiff base ligand incorporating 1,2,4-triazole and 4-(benzyloxy)benzaldehyde moieties

Abstract

A Schiff base ligand named 4-(((5-mercapto-4H-1,2,4-triazole-4-yl)imino)methyl)-(benzyloxy)benzene (HL) and its bioactive series of Ni(II), Cu(II), Zn(II) and Cd(II) metal complexes having 1:1 and 2:1 ligand-to-metal ratio, have been synthesized. All the synthesized compounds were fully characterized by IR, 1H-NMR, elemental analysis, absorbance (UV-Vis.) and mass spectra. Furthermore, the molecular structure of the Schiff base was established by single-crystal X-ray diffraction analysis. Additionally, computational investigations of the compounds were conducted using the DFT/B3LYP method. This analysis involved the determination of FMO energy values, as well as the calculation of quantum chemical parameters. The binding effect of metal ions on the ligand's fluorescence intensity was probed using fluorescence spectroscopy. The thermal stability and kinetic parameters of the complexes were determined using TGA (Thermogravimetric Analysis) analysis via the Coats–Redfern method. The docking studies, actively explored the interaction between Schiff base ligand and protein receptor molecules of Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Candida albicans. To assess the therapeutic potential, an in silico ADMET model was employed, revealing that the synthesized molecules exhibit drug-like properties. The Schiff base and all the derived metal complexes were screened for their antimicrobial potential against bacterial species like Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli and fungus Candida albicans.