Biological Activity Of Transition Metal Complexes Of 4- Formylpyridine Thiosemicarbazone; Equilibrium Studies

Metal complexes of 4-Formylpyridinethiosemicarbazone, H4FPT (L) with Zn(II), Cd(II) and Hg(II) were prepared and characterized by various spectro-analytical techniques such as elemental analyses, molar conductance, LC-MS, TGA, IR and 1H-NMR. Elemental analyses and LC-MS studies reveal the composition as ML2 for all the complexes. Equilibrium studies were carried out in 70% v/v DMF-water medium to calculate dissociation constant of H4FPT and the stability constants of complexes with Zn(II) and Cd(II) ions in solution. H4FPT acts as monobasic ligand with pKa value of 11.60. Stability constants of 1:1 and 1:2 complexes of M(II)-H4FPT followed Irving-William order of stability constants. H4FPT and its complexes showed moderate to good activity against gram positive and gram negative bacterial strains.