Synthesis and antibacterial study of a new azo-Schiff base ligand and Cu-complex

The study involved preparing a new Azo-Schiff base ligand, created by condensing 4-aminoacetophenone with 2,5-dichlorophenol. The resulting Schiff base amine served as a precursor for synthesizing the azo-Schiff ligand through the coupling of the diazonium salt amine with 4,5-diphenylimidazole, forming the desired ligand. Both the ligand and Cu(II) complex were characterized using various spectroscopic techniques, including infrared spectroscopy, ¹H NMR, ultraviolet-visible spectroscopy, and CHN elemental analysis. The optimal conditions for complex formation were also identified, such as pH effect (7), complex conductivity (71.5 μS/cm), and magnetic susceptibility measurements, which showed a value of 2.175 B.M., indicating an octahedral geometry around the Cu(II) center. Tests against Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli demonstrated that the prepared complex exhibited notable activity against these bacteria. KEY WORDS: Azo-Schiff ligand, 4-Aminoacetophenone, 2,5-Dichlorophenol, Cu(II) complex, Antibacterial activity Bull. Chem. Soc. Ethiop. 2026, 40(4), 811-822. DOI: https://dx.doi.org/10.4314/bcse.v40i4.7