Abstract: In an aqueous solution and under the sensitization of acridine yellow(AY) or acridine orange(AO), the photoisomerization of bicyclo [2.2.1] hepta-2,5-diene-2,3-dicarboxylic acid(N) was investigated. The quantum yields of sensitized photoisomerizations for AY and AO are 0.33 and 0.31, respectively. Since the reaction medium is water which is safe and inexpensive, the sensitizers can harvest sunlight effectively and the preparation of water-soluble norbornadiene derivative is very easy, this photo reaction system is promising for solar energy storage. A mechanism involving electron transfer was proposed from the analysis of fluorescence quenching and thermodynamic discussion.

Key words: bicyclo-heptadiene-dicarboxylic acid, acridine yellow, acridine orange, photoinduced valence isomerization, photoinduced electron transfer