Fig. 8. (Top) Fluorescence spectra of the reaction mixture before and after irradiation, and the diene 25 (c = 0.1 mm, irradiation at λ = 350 nm). (Bottom) Absorption spectra of the reaction mixture before and after irradiation (c = 0.1 mm), the alkyne A-1 and the diene 25 (c = 0.05 mm).