Emission and absorption spectra of some substituted 4-hydroxypyrimidines

Article abstract of DOI:10.1016/0584-8539(80)80009-2

The fluorescence, phosphorescence and absorption spectra of 5,6-dimethyl-2-dimethylamino-4-hydroxypyrimidine (1), 5-n-butyl-2-dimethylamino-4-hydroxypyrimidine (2), and 5-n-butyl-2-ethylamino-4-hydroxypyrimidine (3) have been obtained in organic media and in aqueous solution at different pH values.The spectra reveal that the pyrimidines exist principally as cations at low pH, neutral species at pH values around 7 and as anions at high pH.The pK values for the ground state of compounds (1)-(3) have been measured as have the pK* values for the first excited singlet state.