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, 1 H NMR, 13 C NMR, ESI-mass spectra, elemental analysis, molar conductance, thermogravimetric studies and magnetic susceptibility measurements. On the basis of elemental and spectral studies, sixcoordinated 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.

Complexes of Cu(II), VO(IV), Mn(II), Co(II), Ni(II) and Zn(II) with a Schiff base derived from 2-(aminomethyl)benzimidazole and thiophene-2carbaxaldehyde (1-(1H-benzimidazol-2-yl)-N-[(E) thiophenylmethylidene] methanamine-BNTM) were successfully synthesized. The complexes have been characterized using chemical analysis, spectroscopic methods (IR, UV-Visible, 1 H-NMR, 13 C-NMR and ESR), Thermal studies, conductometric and magnetic data. According to these data, we proposed an octahedral geometry to all the metal complexes. Antibacterial activity of the ligand and its metal complexes were studied against two gram-negative bacteria; Escherichia coli, Pseudomonas aeruginosa and two gram-positive bacteria; Bacillus subtilis, Staphylococcus aureus. It has been found that all the complexes are antimicrobially active and show higher activity than ligand.