The effects of alkylation of the 4-amino group, polarity and viscosity
of a solvent, and temperature on the fluorescence of N-(2,4-dimethylp
henyl)imides of 4-amino-1,8-naphthalenedicarboxylic acid were studied.
A decrease in the temperature and polarity of a solvent and an increa
se in its viscosity cause the rate of radiationless deactivation of 4-
dimethylaminonaphthalimide to decrease and have almost no effect on th
e rate of emissive deactivation of excited state. The abnormally low e
fficiency of fluorescence of 4-dimethylaminonaphthalimide in polar low
-viscosity media at room temperature is associated with the formation
of a nonfluorescent charge-transfer state. The increase in the sate of
radiationless deactivation of 4-aminonaphthalimide in the alkylation
of its amino group is associated with the increase in its electron-don
or ability.