Novel thiadiazole‐derived Schiff base ligand and its transition metal complexes: Thermal behaviour, theoretical study, chemo‐sensor, antimicrobial, antidiabetic and anticancer activity

Abstract

Novel thiadiazole‐based Schiff base ligand (L) and their Co(II), Ni(II), Cu(II) and Zn(II) metal complexes have been prepared and characterized using elemental analysis, IR, 1H‐NMR, 13C‐NMR, UV‐vis spectroscopy, EPR, thermal analysis, magnetic moment and conductometric measurements. Based on the above studies, the metal complexes were found to exhibit octahedral geometry except that of Zn(II) complex, which is tetrahedral. The thermal stability and the presence of coordinated water molecules of the metal complexes were investigated by thermogravimetric analysis. Geometry optimization of the ligand and its Zn(II) complex was performed using B3LYP functional with LANL2DZ basis set. The HOMO–LUMO energy gap, molecular properties, NLO, polarizability and MEP were theoretically calculated. The fluorescence spectra of the ligand revealed that the sensor could detect K+ ions over the pool of other metal ions. The Schiff base ligand and its metal complexes have been screened for their antimicrobial activity against different bacterial and fungal species using inhibition zone technique and by well diffusion methods. The results revealed that metal complexes have more activity than that of the ligand. The anticancer activities of Co(II) and Cu(II) complexes have been studied towards breast cancer (MCF‐7) cell lines. The Co(II) and Cu(II) complexes have also been evaluated for in vitro α‐amylase inhibitory activity.