Synthesis, Characterization, Molecular Docking, Cytotoxicity, and Antimicrobial Activity of Schiff Base Ligand and Its Metal Complexes

ABSTRACT A Schiff base ligand (L) was synthesized via condensation of N ‐(1‐naphthyl)ethylenediamine dihydrochloride with phthalaldehyde. The ligand was characterized by FT‐IR, UV–Vis, 1 H NMR, mass spectrometry, and elemental analysis (C, H, N). Five metal complexes (Co(II), Ni(II), Cu(II), Zn(II), and Cd(II)) were prepared with the ligand in a 1:1 (M:L) ratio using an aqueous ethanol solution. The complexes were characterized by FT‐IR, UV–Vis, mass spectrometry, and elemental analysis (C, H, N). Additionally, 1 H NMR spectroscopy was employed for Cd(II) complex. Antimicrobial activity of the ligand and its metal complexes against pathogenic bacteria ( K. pneumoniae , E. coli , S. aureus , and S. epidermidis ) and fungus ( C. albicans ) were evaluated using the agar well diffusion method. All compounds exhibited inhibitory effects with zone diameters ranging from 8 to 16 mm. The ligand and complexes also displayed significant anticancer activity against a mammary carcinoma cell line. Among them, Zn(II) and Cu(II) complexes demonstrated the highest inhibitory effects (70.68% and 70.57%, respectively), followed by the ligand (61.35%) and Co(II), Cd(II), and Ni(II) complexes (60.34%, 58.96%, and 41.63%, respectively). IC50 values followed a similar trend, ranging from 31.69% (Co(II)) to 165.7% (Cd(II)). Molecular docking studies indicated strong binding affinities of the ligand and the Zn(II) complex to the estrogen receptor.