Structural, spectroscopic, electrochemical and antibacterial studies of some new nickel(II) Schiff base complexes

• Three new Ni(II) Schiff base complexes showed potential antibacterial activity.
• The cyclic voltammetric behavior of these complexes are also reported and discussed.
• The crystal structures were determined by X-ray diffraction.

Three new complexes of Ni(II) with tridentate Schiff base ligand, have been synthesized from reaction of the ligand sapH2 (salicylidene-2-aminophenol) with Ni(OAc)2·4H2O in the presence of relevant amine: imidazole (1), 1-methylimidazole (2), and morpholine (3). These complexes have been characterized by FT-IR, 1H NMR, elemental analysis and UV–Vis spectroscopy. The crystal structures of the complexes were established by X-ray crystallography. The single crystal X-ray diffraction studies show square planar geometry around Ni(II) in all three complexes, and conform to the results obtained by spectroscopic studies. The electrochemical investigation of these complexes at a carbon paste electrode in water solution indicates that the Ni(II/III) oxidation process was irreversible. Our studies showed that the nickel complexes exhibit good antibacterial activity, and their antibacterial activity is higher than that of the ligand against both gram positive and gram negative bacteria.

Three new Ni(II) complexes were prepared and investigated. These complexes were characterized by FT-IR, 1H NMR, UV–Vis spectroscopy and elemental analysis. The crystal structures were determined by X-ray diffraction. The crystal structures of the complexes were established by X-ray crystallography. It was found that Ni(II) complexes have four coordinate sites in the solid state organized in a square-planar fashion, in accordance with the results of the spectroscopic studies. The electrochemical reduction of these complexes at a carbon paste electrode in water solution indicates that the oxidation potential of Ni(II/III) is irreversible. Our studies showed that the nickel complexes exhibit good antibacterial activity, and their antibacterial activity is higher than that of the ligand against both gram positive and gram negative bacteria.Figure optionsDownload as PowerPoint slide