A modern technique for preparation of zinc(II) and nickel(II) nanometric oxides using Schiff base compounds: synthesis, characterization, and antibacterial properties

The purpose of the work reported in this paper was the preparation and characterization of Zn(II) and Ni(II) nanometric oxides by using a simple Schiff compound as precursor for complexation then thermal degradation at 600 A degrees C. Metal complexes [Ni(L)(2)(Cl)(2)] and [Zn(L)(2)](NO3)(2), where L is the Schiff base formed by condensation of 2-thiophenecarboxaldehyde with phenylhydrazine, were prepared and characterized by elemental analysis and by magnetic and spectroscopic measurements (infrared, Raman, X-ray powder diffraction, and scanning electron microscopy). Elemental analysis of the chelates suggests the stoichiometry is 1:2 (metal-ligand). Infrared spectra of the complexes are indicative of coordination of the nitrogen of the phenylhydrazine (-Ph-NH-) group and the sulfur atom of the thiophene ring with the central metal atom. Magnetic susceptibility data and electronic and ESR spectra suggest a distorted octahedral structure for the Ni(II) complex and tetrahedral geometry for the Zn(II) complex. The Schiff base and its metal chelates were screened for in-vitro activity against four bacteria, two Gram-positive (Bacillus subtilis and Staphylococcus aureus) and two Gram-negative (Escherichia coli and Pseudomonas aeruginosa), and two strains of fungus (Aspergillus flavus and Candida albicans). The metal chelates were shown to have greater antibacterial activity than the free Schiff-base chelate.