Ligating properties of 5-nitrobarbituric acid

The dissociation constant of 5-nitrobarbituric acid and the stability constants of its Co-II, Ni-II and Cu-II, complexes were determined potentiometrically. The thermodynamic parameters of dissociation were evaluated. The effect of solvents on the pK values was explained from aquation and solvation views. 5-Nitrobarbituric acid solid complexes of Mn-II, Co-II, Ni-II, Cu-II and Zn-II, and the mixed metals, Fe-Co, Fe-Ni were prepared and characterized based on elemental analysis, spectra (electronic, IR, and Mossbauer), magnetism and thermal measurements.