Synthesis and biocidal activity of Zn(II) complexes of some 2,2'-substituted diphenylamines

Binary as well as ternary complexes of Zn(II) with diphenylamine-2,2'-dicarboxylic acid (dpdc), diphenylamine-2-amino-2'-carboxylic acid (dpac), diphenylamine-2-hydroxy-2'-carboxylic acid (dphc), diphenylamine-2-mercapto-2'-carboxylic acid (dpmc), and N-(2-pyridino) anthranilic acid (npa) have been synthesized and characterized by their elemental analysis, IR spectral data, and molar conductance measurements. Antimicrobial activity of these ligands and their respective Zn(II) complexes have been determined on gram positive (Staphylococcus aureus) and gram negative (Escherichia coli) bacteria and on Aspergillus niger and Aspergillus nidulense, two common fungi by the serial dilution method. A considerable increase in the biocidal activity of these ligands on being coordinated with the metal ion has been reported in terms of their minimum inhibitory concentration (MIC) values.