Nano Sized Schiff Base Complexes with Mn(II), Co(II), Cu(II), Ni(II) and Zn(II) Metals : Synthesis, Spectroscopic and Medicinal Studies

Metal chelates, [M(HL)2(H2O)2]X2 (where M= Mn(II), Co(II), Cu(II), Ni(II) or Zn(II), X= NO3–or Cl– and HL= Schiff base moiety), have been prepared and characterized by elemental analysis, magnetic and spectroscopic measurements (infrared, X-ray powder diffraction and scanning electron microscopy). Elemental analysis of the metal complexes was suggested that the stoichiometry is 1:2 (metal-ligand). Infrared spectra of the complexes agree with the coordination to the central metal atom through the nitrogen of the 2-chlorophenyl hydrazine (–Ph–NH-) group and the sulfur atom of the thiophene ring. The electronic spectra suggest a distorted octahedral geometry for all Schiff base complexes. The Schiff base and its metal chelates have been screened for their in vitro antibacterial activity against four bacteria, gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli) and two strains of fungus (Aspergillus flavus and Candida albicans). The metal chelates were shown to possess more antibacterial activity than the free Schiff-base chelate.