SYNTHESIS, PHYSIOCHEMICAL PROPERTIES AND BIOLOGICAL ACTIVITY OF N,O,O DONOR SCHIFF BASE AND ITS CU(II), NI(II), CD(II), MN(II) AND CO(II) COMPLEXES

A Schiff base ligand (H2L), {2-((2-hydroxybenzylidene)amino)benzoic acid}(C14H11NO3) containing nitrogen-oxygen donor atom was prepared by the condensation of salicylaldehyde and anthranilic acid and coordinated with Cu(II), Ni(II), Cd(II), Mn(II) and Co(II) ions. The Schiff base and its metal complexes were characterized by elemental analysis, FT-IR, ESI-MS, electronic absorption spectroscopy and some of their physicochemical properties were determined. The overall reaction was monitored by TLC analysis. The analytical and theoretical data showed that the metal ligand stoichiometry in the complexes was 1:1. Molar conductance study have shown that all the complexes were non electrolytic in nature. FT-IR studies suggested that Schiff base acts as deprotonated tridentate ligand and metal ions are attached with the ligand- by azomethine nitrogen, oxygen atom of deprotonated hydroxyl group and deprotonated oxygen of the carboxyl group of ligand respectively. Thermal analysis (TGA and DTG) data suggested that, a small weight loss occurred in the range of 40 degrees C - 80 degrees C from the complex which is assigned to the loss of lattice water and maximum weight loss in the range of 280-450 degrees C is attributable to the loss of coordinated water present in all complexes. These data also showed that most of the complexes were thermally stable up to 200 degrees C. All the complexes showed good antimicrobial activity compared to ligand and commercial standard.