Transition metal complexes of triazole-based bioactive ligands: synthesis, spectral characterization, antimicrobial, anticancer and molecular docking studies

In the present research work, four new heterocyclic Schiff base ligands (1–4) were synthesized by the condensation of 4-(4-amino-5-mercapto-4H-1,2,4-triazol-3-yl)phenol with salicylaldehyde derivatives in 1:1 molar ratio. The synthesized Schiff base ligands were allowed for complexation with Co(II), Ni(II), Cu(II), Zn(II) metal ions. The structure of the newly synthesized compounds (1–20) was elucidated with the help of various spectral and physicochemical techniques. Spectroscopic data confirm the tridentate nature of ligands which coordinate to the metal via deprotonated oxygen, azomethine nitrogen and thiol sulphur. Conductivity data showed the non-electrolytic nature of complexes. Furthermore, the synthesized compounds were evaluated for their in-vitro antimicrobial activity against four pathogenic bacterial strains and two pathogenic fungal strains. The observed results of microbial activity reveals that compound 3 and its complexes (13–16) were found most potent against the pathogenic strains. In addition, the anticancer activity of all the synthesized compounds was evaluated against human carcinoma cell lines i.e. HCT-116, DU145 and A549 using MTT assay. Among the tested compounds 12, 19, and 20 were found to show promising potency against the cancer cell lines. To rationalize the preferred modes of interaction of most potent compounds with the active site of human EGFR protein (PDB id: 5XGM), molecular docking studies were performed. GRAPHICAL ABSTRACT: [Image: see text] SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s11164-021-04621-5.