Synthesis¸ Characterization and Biological Activity of a Schiff Base Derived from 3-Ethoxy Salicylaldehyde and 2-Amino Benzoic acid and its Transition Metal Complexes

Abstract

A new Schiff base, 3-ethoxy salicylidene amino benzoic acid (ETSAN), has been synthesized from 3-ethoxy salicylaldehyde and 2-amino benzoic acid. Metal complexes of the Schiff base were prepared from nitrate/chloride salts of Ni(II), Co(II) Cu(II) and Zn(II) in an alcoholic medium. The complexes were non-electrolytes in dimethyl sulfoxide solvent (DMSO). The chemical structures of the Schiff-base ligand and its metal complexes were confirmed by various spectroscopic studies like IR, UV-VIS, 1H NMR, 13C NMR, ESI-mass spectra, elemental analysis, molar conductance, thermogravimetric studies and magnetic susceptibility measurements. On the basis of elemental and spectral studies, six-coordinated geometry was assigned to these complexes. In the light of these results, it is suggested that this ligand acts as neutral and tridentate and coordinates to each metal atom by azomethine nitrogen and oxygen atoms of hydroxyl group of the 3-ethoxy salicylaldehyde, besides the hydroxyl group of the carboxyl group of 2-amino benzoic acid. The mass spectral data confirms the monomeric structure of the metal complexes while the TGA studies confirm the presence of water molecules in the complex. The free Schiff base and its complexes have been tested for their antibacterial as well as antifungal activity by using disc diffusion method and the results discussed. Keywords: Schiff base; 3-ethoxy salicylaldehyde; 2-amino benzoic acid; Metal complexes; Antibacterial activity; Antifungal activity. © 2010 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved. DOI: 10.3329/jsr.v2i3.4899 J. Sci. Res. 2 (3), 513-524 (2010)