Fluorescence of an organic radical cation (5,10-dihydro-5,10-dimethylphenazine⋅+) in liquid solution at room temperature

The fluorescence and fluorescence excitation spectra of the radical cation of 5,10-dihydro-5,10-dimethylphenazine (DHDMP⋅+) have been recorded in liquid solution at room temperature. The fluorescence lifetime (0.47 ns) has been measured in an organic glass at 77 K and the fluorescence quantum yield (1×10−3) has been estimated. This is virtually the only organic radical cation for which all the above-mentioned photophysical properties have been obtained in an organic solvent and the only system for which the spectra are available at room temperature. This is due to the unusually high stability of the DHDMP⋅+ radical cation and is an important step forward with regard to practical applications using radical cations.