Polarographic Oxidation of Diaminopyrimidines

TLDR: The effects of varying concentrations, temperature, pH, buffer concentration, rate of rotation of electrode and rate of scanning of potential were determined in the polarographic oxidation of polyamino-and aminohydroxy-pyrimidines as mentioned in this paper.

Abstract: The polarographic oxidation of 2, 5-diaminopyrimidine (IV) and 4,5-diaminopyrimidine (V) at the rotating Pt microelectrode in aqueous buffered solutions was studied. The effects of varying concentrations, temperature, pH, buffer concentration, rate of rotation of electrode and rate of scanning of potential were determined. The limiting currents are diffusion controlled and proportional to concentration up to 1 × 10−3 M for (IV) and 2 × 10−4 M for (V). The overall reaction is irreversible and probably involves two electrons per molecule to give an unstable product with a quinonimine structure. The dependence of E½ on pH in the anodic polarography of twelve more polyamino- and aminohydroxy-pyrimidines was determined. Huckel type MO calculations were carried out for the pyrimidines and the energies calculated for the highest occupied MOs were correlated with E°½ values.