Synthesis, characterization, crystal structure and bioactivities of a new potential tridentate (ONS) Schiff base ligand N-[2-(benzylthio) phenyl] salicylaldimine and its Ni(II), Cu(II) and Co(II) complexes

A series of new bichelated complexes of the formula [M(L)2]·H2O were synthesized from the reaction of N-[(2-benzylthio)-phenyl] salicylaldimine (HL), 1, a new tridentate (O, N, S donor) potential Schiff base with metal salts in methanol medium. These compounds were characterized by elemental analyses, FT-IR, UV–Visible and magnetic susceptibility studies. The crystal structures of the ligand 1 as well as two nickel(II) complexes [Ni(L)2]·H2O, 2 and 3, were determined by X-ray diffraction studies. The nickel atom is coordinated to two oxygen atoms, two nitrogen atoms and two sulfur atoms in bichelated fashion of the ligand, 1 indicating that the metal atom is in a slightly distorted octahedral environment. The bioactivity studies showed that the ligand and the complexes exhibit considerable antibacterial and antifungal activities against Bacillus subtilis (Gram +ve), Klebsiella pneumonia (Gram −ve) and Candida albicans.

Graphical abstractA new potential tridentate (ONS) Schiff base ligand, N-[2-(benzylthio)phenyl] salicylaldimine, and its Ni(II), Cu(II) and Co(II) complexes (four complexes) were synthesized and characterized by spectral (1H NMR, FT-IR, UV–Vis), molar conductivity, magnetic measurement and X-ray diffraction methods [the latter for the ligand and two Ni(II) complexes]. X-ray diffraction data, magnetic susceptibility measurements and electronic spectra revealed a slightly distorted octahedral arrangement for the Ni(II) complexes. Antimicrobial studies showed that the ligand and the four metal complexes are active against Bacillus subtilis, Klebsiella pneumonia and Candida albicans.Figure optionsDownload full-size imageDownload as PowerPoint slide