A new series of Ni(II), Cu(II), Co(II) and Pd(II) complexes with an ONS donor Schiff base: Synthesis, crystal structure, catalytic properties and bioactivities

A new series of bichelated complexes of the formula M(L)2 and M(L)Cl, where M = Ni(II), Cu(II), Co(II) and Pd(II) and L = a deprotonated Schiff base, were synthesized from the reaction of 5-bromo N-[(2-benzylthio)-phenyl] salicylaldimine (HL, 1), a new potential tridentate (O, N, S donor) Schiff base, with metal salts in methanol medium, and the complexes were characterized by a variety of physicochemical techniques, namely elemental analyses, FT-IR, 1H NMR and UV–Vis spectroscopies, thermogravimetric analysis and conductivity studies. The coordination mode of the palladium complex was determined by single crystal X-ray diffraction studies and was found to possess a distorted square planar structure with the ligand coordinated as a uninegatively charged tridentate chelating agent via the hydroxyl oxygen, azomethine nitrogen and thioether sulfur atoms, and the remaining fourth coordinating site was filled by a chloride ion. The copper complex shows very good catalytic activities towards the oxidation of organic thioethers to the corresponding sulfoxide and sulfones using H2O2 as the oxidant. The ligand and complexes exhibited considerable antibacterial and antifungal activities against Klebsiella pneumoniae (ATCC 10536), Staphylococcus aureus (ATCC 11632) and Candida albicans.

A new series of bichelated complexes of the formula M(L)2 and M(L)Cl, where, M = Ni(II), Cu(II), Co(II) and Pd(II) and L = deprotonated Schiff base, were synthesized from 5-bromo N-[(2-benzylthio)-phenyl] salicylaldimine (HL, 1). The ligand and its complexes were characterized by elemental analyses, FT-IR, 1H NMR and UV–vis spectroscopies, thermogravimetric analysis and conductivity studies. The crystal structure of the palladium complex was determined by single crystal X-ray diffraction studies. The copper complex shows very good catalytic activity towards the oxidation of organic thioethers. Again, the ligand and the complexes exhibited considerable antibacterial and antifungal activities.Figure optionsDownload as PowerPoint slide