Several intramol. bridging enone compounds were synthesized and characterized. The mol. in which the double bond is bridged to form a ring has very strong fluorescence emission. By contrast, the mol. in which the double bond is not bridged or located outside the bridged ring has very low fluorescence quantum yield. The "neg. solvatokinetic effect" and the strong dependence of fluorescence intensity on the solvent polarity for these compounds were also observed A preliminary explanation is proposed.

Key words: FLUORESCENCE DYES, KETENE, CHEMILUMINESSENCE, LASER DYES, PHOTOSENSITIVE DRUG