ELECTRONIC ABSORPTION AND FLUORESCENCE OF PHENYLETHYNYL-SUBSTITUTED ACENES

Substitution of acenes la, IIa and IlIa with the phenylethynyl group substantially increased quantum yields of fluorescence, and produced large shifts to longer wavelengths in the visible absorption and fluorescence spectra. A nearly constant displacement toward the red of 100 mµ in the fluorescence emission was observed for the meso-substituted bis(phenylethynyl)acenes lb, IIb, and IIIb, when compared with the parent hydrocarbons. The spectral data indicate that the ethynyl group is a better conductor of electronic effects in the excited state than in the ground state. © 1969, American Chemical Society. All rights reserved.