Picosecond laser photolysis study of cycloreversion reaction of a diarylethene derivative in polycrystals: Multiphoton-gated reaction

Cycloreversion processes of a photochromic diarylethene derivative, bis(2-methyl-5-phenylthiophen-3-yl)perfluorocyclopentene, in crystalline phase was investigated by means of the picosecond laser spectroscopy. In addition to the cycloreversion process in the S, state with 50 ps time constant, drastic enhancement of the reaction yield was observed by the picosecond laser exposure. The excitation intensity effect of the reaction yield and dynamic behaviors revealed that successive multiphoton absorption process leading to higher excited states opened the efficient cycloreversion process. The dynamics and mechanisms of the multiphoton-gated reaction in the crystal were discussed by comparing the present results with those in solutions. (c) 2007 Elsevier B.V. All rights reserved.