Synthesis, Characterization and in vitro Antibacterial Activities of Cu(II) and Ni(II) Complexes of N-(benzo[d]thiazol-2-ylcarbamothioyl)benzamide
A chelating ligand, N-(benzo[d]thiazol-2-ylcarbamothioyl)benzamide (N-btcb), with sulfur and oxygen donor atoms, was synthesized using 2-aminobenzothiazole and benzoyl isothiocyanate. Cu(II) and Ni(II) complexes of N-btcb were prepared by refluxing chelating ligands with the respective metal acetates in acetone. Structures of both the complexes were established using elemental analysis and spectroscopic methods (IR, 1H NMR, electronic spectra) and physical properties like colour, solubility, melting point, and thermal stability were recorded. Structural analysis suggests that for both the complexes N-btcb is coordinated to the metal ion through the sulfur and oxygen donor atoms, forming a six-membered ring. The coordination geometry of the Cu(II) complex was found to be distorted octahedral, and that of the Ni(II) complex was found to be octahedral. Biological activity (in vitro) assessments suggest slightly improved antibacterial activities for both the metal complexes compared to the organic ligand, except against E. coli.