Comprehensive characterization of benzothiazole-hydrazone metal (II) complexes via spectroscopic, biological assignment, electrochemical, DFT, and molecular docking approaches

An inventive benzothiazole hydrazone Schiff base ligand (H2p-NP), and its cobalt(II), nickel(II), and copper(II) complexes were synthesized and characterized via 1H/13C-NMR, FTIR, UV-Vis, C.H.N. microanalysis, magnetic moment susceptibility, EDX, TGA, DRS, ESR, SEM, and mass spectroscopy. The analytical and spectral data indicate that the coordination nature of H2p-NP with Co(II) and Cu(II) is a neutral bidentate, and produces octahedral and square-planar complexes, respectively, while a neutral tridentate octahedral complex is formed with Ni(II). DFT calculations supported the proposed geometries. The Cu(II) complex exhibited clear redox behavior in cyclic voltammetry. Antimicrobial evaluation toward Staphylococcus aureus, Escherichia coli, and Candida albicans revealed that the Cu(II) complex showed the greatest activity among the tested compounds. Molecular docking (MOE) further confirmed the high binding potential of the active complex sites toward relevant biological targets.