BIOACTIVE PENTA-COORDINATED DIORGANOTIN(IV) COMPLEXES OF PYRIDOXALIMINE SCHIFF BASES

Diorganotin(IV) complexes of an extended system derived from the condensation of pyridoxal hydrochloride with 2-amino phenol (H2L1), 2-amino-4-methyl phenol (H2L2), 2-amino-4-chloro phenol (H2L3), 2-amino-4-nitro phenol (H2L4), 1-amino-2-naphthol hydrochloride (H2L5) have been synthesized by the reaction of dichlorodiorganotin(IV) in a 1:1 molar ratio with these ligands. Spectral studies (IR, H-1, C-13, Sn-119 NMR) along with physical data evidenced the formation of penta-coordinated species with the ligands acting as tridentate (ONO) with oxygen occupying the axial positions, and nitrogen at one of the equatorial positions. The ligands and their organotin complexes have been evaluated for antimicrobial activity against phytopathogenic fungi Candida albicans and Aspergillus niger at 25 +/- 1 degrees C and bacteria Bacillus subtilis, Escherichia coli, and Staphylococcus aureus at 37 +/- 1 degrees C. The activities of the ligands have been enhanced on complexation and the results indicate that they exhibit significant antimicrobial properties.