SYNTHESIS AND BIOLOGICAL-ACTIVITY OF THE SCHIFF-BASE N,N'-BIS(SALICYLIDENE)THIOUREA AND ITS COMPLEXES OF COPPER(II), NICKEL(II) AND ZINC(II)

The Schiff base N,N'-bis(salicylidene)thiourea and its complexes of co pper(II), nickel( II) and zinc(II) have been synthesized and character ized by elemental analyses, molar conductivity measurements, thermal a nalyses, infrared and electronic spectral data. The Schiff base ligand has been further identified by H-1 NMR and mass spectra. The results suggest that the Schiff base behaves as a quadridentate ligand attache d to the metal ion through the phenol oxygen and imino nitrogen atoms, The biological activities of these compounds to scavenge superoxide f ree radicals and poison Oncomelania hupensis (a kind of an intermediat e host of blood fluke) are also reported.