Differential Pulse Polarographic Study of Mercury Complexes with Some Substituted Pyrimidines in Binary Acetonitrile-Dimethylformamide Mixtures

The complex formation of Hg2+ ion with five synthesized substituted pyrimidines in binary acetonitrile-dimethylformamide (AN-DMF) mixtures was studied by differential pulse polarography at 25 graduate C. The stoichiometry and stability of the complexeswere determined by monitoring the shift in the Hg2+ differential pulse peak potential against the pyrimidines concentration. In all cases studied, itwas found that the stability of the resulting 1:1 complex decreases drastically by increasing the amount of dimethylformamide in the binary mixtures. The observed stability order in a given solvent mixture is discussed in terms of the solvating ability of the solvent, donor site number, and steric hindrance on the pyrimidines.