Synthesis, characterization, and in vitro antimicrobial studies of new Mn(II), Fe(III) and Ni(III) complexes based on 4-[(2 sulfanylphenyl)diazenyl]naphthalen-1-ol ligand

Abstract

This study successfully synthesized three novel metal complexes: MnSDN, FeSDN, and NiSDN, and thoroughly characterized them using UV spectroscopy, infrared (IR) spectroscopy, mass spectrometry, elemental analysis, conductivity and magnetic measurements, as well as thermogravimetric analysis (TGA). The IR spectral analysis indicates that the azo ligand, 4-[(2-sulfanylphenyl)diazenyl]naphthalen-1-ol (SDN), coordinates with metal ions via its nitrogen atoms in the azo (-NN-) bond and sulfur atoms in the thiol (-SH) moiety. Thermal analysis (TGA) further revealed the quantity & binding sites of H₂O molecules within the complex compounds. Additionally, in vitro assessments of the antibacterial & antifungal activities of the ligand and its metal complex components were conducted against various pathogenic bacteria & fungi. Particularly, the metal complex products revelation significantly greater inhibitory effects on certain microorganisms compared to the uncoordinated ligand. Among the tested compounds, the metal complexes demonstrated superior biological activity, whereas the free ligand showed the least efficacy. These promising results suggest that these metal complexes possess potential physiological effects and may serve as valuable candidates for various medical applications in the future.