Synthesis, Spectroscopic Characterization, DFT Calculations, Antibacterial Activity, and Molecular Docking Analysis of Ni(II), Zn(II), Sb(III), and U(VI) Metal Complexes Derived from a Nitrogen-Sulfur Schiff Base

Abstract: A series of metal complexes of Ni(II), Zn(II), Sb(III), and U(VI) were synthesized by reacting the corresponding metal salts with the Schiff base ligand, S-benzyl-3-(4-methoxybenzylidine)dithiocarbazate. These metal complexes were structurally characterized by elemental analysis, IR, 1H and 13C NMR, and electronic absorption spectroscopy. The molecular structures of the synthesized complexes were also explored by quantum computational calculations based on the density functional theory (DFT). The outcome of the spectroscopic and theoretical data revealed that the ligand was linked with metals through N and S donor atoms of the Schiff base. Based on analytical data, metal-ligand stoichiometry in complex formation was found to be a 1 : 2 molecular ratio. Analytical data allied with spectroscopic studies spilled that the Ni(II) and Zn(II) complexes preferred square planar geometry and tetrahedral geometry, whereas Sb(III) and U(VI) complexes offered octahedral geometry, respectively. Both the Schiff base and its complexes were screened for antibacterial activity against some pathogenic bacterial species.