CHEMILUMINESCENT SYSTEMS

Another functional class of organic materials, electronegatively substituted vinyl compounds, have been observed to yield relatively bright chemiluminescence in autoxidation reactions in basic, aprotic polar solvents. 4-Dimethyl amino benzoin has been found to produce a peak emission intensity significantly greater than that of benzoin. The relative emission intensities of indoles are orders of magnitude greater in aprotic solvents than in aqueous solution. For 2,3dimethylindole this ratio is 1,000,000. Luminescence spectra have been obtained for benzoin, 2,3dimethylindole and indole-5-carboxylic acid as a function of degree of reaction and base concentration. The observed chemiluminescence spectrum for benzoin oxidation corresponds to the fluorescence spectrum of benzil although benzil fluorescence has not been observed in the luminescence spectrum of oxidized benzoin solutions. The chemiluminescence spectrum of 2,3-dimethylindole corresponds to the fluorescence spectrum of a stable reaction product. The chemiluminescence spectrum of indole-5-carboxylic acid is similar to that of 2,3-dimethylindole but does not correspond with the fluorescence spectrum of any observed stable product.