Studies on the synthesis, characterisation and antimicrobial activity of new Co(II), Ni(II) and Zn(II) complexes of Schiff base derived from ninhydrin and glycine.

For the first time, Co(II), Ni(II) and Zn(II) complexes have been synthesized involving an intermediate Schiff base, indane-1,3-dione-2-imine-N-acetic acid the condensed product of ninhydrin and glycine. These coloured complexes were characterised by elemental analysis, molar conductivity, thermogravimetric analyses/differential thermal analysis, infrared, magnetic susceptibility, NMR and electronic spectral studies. Mechanisms for their formation have been proposed. The experimental studies reveal that the complexes possess octahedral stereochemistry whereas the Schiff base behaves as a monobasic tridentate ligand. A molecular structure for the metal complexes is also proposed. A comparative study of the antimicrobial activity of ninhydrin and the corresponding metal complexes against Escherichia coli, Proteus mirabilis, Staphylococcus aureus and Streptococcus faecalis has been undertaken and the results are discussed.