Synthesis, Spectroscopic Characterization, and Biological Evaluation of (2E,3Z)-3-(((E)-2,4-dichlorobenzylidene)hydrazono)butan-2-one Oxime and Its Fe(II), Cu(II), Co(II), Ni(II), and Mn(II) Complexes

A novel Schiff base ligand, (2E,3Z)-3-(((E)-2,3-dichlorobenzylidene)hydrazono)butan-2-one oxime, was synthesized and characterized, along with its coordination complexes with Mn(II), Fe(II), Cu(II), Zn(II), Cd(II), Hg(II), Ni(II), and Pd(II) ions. The ligand and its metal complexes were characterized using various spectroscopic techniques, including FTIR, NMR, UV-Vis, and elemental analysis, to confirm their structural integrity and coordination behavior. The antibacterial and antifungal activities of the ligand and its complexes were evaluated against a range of pathogenic bacterial strains (e.g., Escherichia coli, Staphylococcus aureus) and fungal strains (e.g., Candida albicans, Aspergillus niger). The metal complexes exhibited enhanced antimicrobial activity compared to the free ligand, with the Cu(II) and Ni(II) complexes showing particularly potent inhibitory effects. The structure-activity relationship suggests that the coordination of metal ions enhances the lipophilicity and interaction with microbial cell membranes, thereby improving bioactivity. These findings suggest potential applications of these complexes in the development of new antimicrobial agents.