Potentiometric and Thermodynamic Studies of 4-Acrylamidobenzenesulfonylazide and Its Metal Complexes in Monomeric and Polymeric Forms

Abstract

4-Acrylamidobenzenesulfonylazide (ABS) was synthesized and characterized by elemental analyses and IR spectroscopy. Proton-monomeric ligand dissociation and metal-monomeric ligand stability constants of ABS with some metal ions were determined potentiometrically in 0.1 M KCl and a 50% (v/v) ethanol-water mixture. In the presence of 2,2'-azobisisobutyronitrile as an initiator, the dissociation and stability constants of ABS were determined in its polymeric form (PABS). The influence of temperature on the dissociation of ABS and the stability constants of its complexes in monomeric and polymeric forms were precisely studied. The pK H value of PABS was found to be higher than that for ABS, indicating that the vinyl group in the monomeric form decreases the electron density and hence reduces the N-H bond strength. The stability constants of the metal complexes with the polymeric form are higher than those of the monomeric form. This reveals that the ligand in a polymeric form can be considered as a better complexing agent.