Synthesis, Characterization and Biological Activity of Mixed Ligand (Imine of Benzidine and 1,10-Phenanthroline) Complexes with Fe(II), Co(II), Ni(II) and Cu(II) Ions

In this paper, binuclear metal complexes of the metal ions Fe(II), Co(II), Ni(II) and Cu(II) were synthesized by the reaction of the primary ligand (imine of benzidine) (H2L) and the secondary ligand (1,10-phenanthroline) (L`) with these metal ions in a molar ratio of 1:2:2, respectively. The complexes were characterized using CHN elemental analysis, FT-IR, UV-Vis, magnetic susceptibility, molar conductivity, 1H NMR, and TGA-DTA thermogravimetric analysis. According to the results obtained from the elemental analysis and spectral measurements where complexes of Fe(II), Co(II) and Ni(II) have octahedral geometry, while the complex with Cu(II) has a square planar geometry. All the prepared complexes are wholly stable and can keep for months without any significant change. The antibacterial activities of the prepared compounds were evaluated with regard to two bacteria species, gram-negative Proteus and Kelbsiella, by using diffusion agar plates. The inhibition zone diameter around the holes indicated the sensitivity of the bacteria to these compounds, where the Klebsiella bacteria were revealed to be more highly sensitive to these compounds than Proteus bacteria. All synthesized complexes showed more significant effects against Kelbsiella and Protea than the antibiotic (Amikacin).