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Polarographic Oxidation of Diaminopyrimidines
Author(s) -
Cohen D.,
Koenigsbuch M.,
Sprecher M.
Publication year - 1968
Publication title -
israel journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.908
H-Index - 54
eISSN - 1869-5868
pISSN - 0021-2148
DOI - 10.1002/ijch.196800079
Subject(s) - chemistry , polarography , diffusion , electrode , microelectrode , limiting , analytical chemistry (journal) , limiting current , aqueous solution , electrochemistry , electron , inorganic chemistry , chromatography , thermodynamics , mechanical engineering , physics , engineering , quantum mechanics
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. Hückel type MO calculations were carried out for the pyrimidines and the energies calculated for the highest occupied MOs were correlated with E°½ values.