Preparation and characterization of some transition metal complexes Co(II), Ni(II), Cu(II), and Zn(II) with a Schiff base ligand and study of their biological activity

A new Schiff base, 2-((benzo[d]thiazol-2-ylimino)methyl)phenol (L1), was synthesized via condensation of 2-hydroxybenzaldehyde with 2-aminobenzothiazole. Complexes of L1 with Co(II), Ni(II), Cu(II), and Zn(II) were prepared and characterized using various techniques, including elemental analysis (CHNS), infrared (FTIR), UV-visible (UV-Vis) and nuclear magnetic resonance (1H, 13C NMR) spectroscopies, thermogravimetric analysis (TGA), magnetic susceptibility, atomic absorption (AAS), molar conductivity, and melting point. The results suggested an octahedral geometry for the complexes and a 1:2 electrolytic nature. The biological activity of the ligand and its complexes was tested, and significant antibacterial activity against selected bacterial strains was observed.