Mononuclear Schiff Base Complexes Derived from 5-Azophenylsalicylaldehyde with Co(II), Ni(II) Ions: Synthesis, Characterization, Electrochemical Study and Antibacterial Properties

In the present research, 1,2-di[N-2-phenylthio-5-azophenylsalicylidene]ethane (H2L ), 1,3-di[N-2-phenylthio-5-azophenylsalicylidene]propane(H2L ) and 1,4-di[N-2-phenylthio-5-azophenylsalicylidene]butane (H2L ) were synthesized. ML, ML and ML complexes were prepared through the reaction of H2L , H2L 2 and H2L 3 with Ni(II) and Co(II) acetate salts. The prepared ligands and their complexes were characterized with FT-IR, H-NMR, elemental analysis, conductivity and magnetic measurements, ESI-mass, UV-Vis spectroscopy and cyclic voltammetry. The complexes had monomeric structure according to the mass spectral data. All of the complexes had a six-coordinated octahedral geometry. The electrochemical behavior of the ligands, Ni(II) and Co(II) complexes was investigated by CV in DMF under argon atmosphere. The results show that the coordination of Ni(II) causes the ligands to be deactivated. The voltammogram of Co(II) complexes shows that the reduction of CoL is harder than CoL and CoL is inactive. Their antibacterial activity was investigated and the complexes exhibited better antibacterial activity than the free ligands against selective bacteria.