Spectral and luminescence properties and photochemical transformations of 7,7,9-trimethyl-6,7-dihydrofuro[3,2-f]quinoline

Spectral, luminescent, and photochemical properties of 7,7,9-trimethyl-6,7-dihydrofuro[3,2-f]quinoline (FDHQ) have been studied in hexane, alcohols, and water. Unlike 1,2-dihydroquinolines without the furo substituent, the fluorescence quantum yields for FDHQ in water and methanol are high (0.4 and 0.2, respectively), thereby indicating a difference in routes of excitation energy degradation in these compounds. The regularities in the FDHQ phototransformations have been studied by steady-state photolysis. The composition and the yield of final products depend on the presence or absence of oxygen in the system to a higher extent than on the solvent nature. This indicates the participation of the triplet excited state in the photo-chemical reactions in oxygen-free systems.