M. Irie, T. Lifka, and Seiya Kobatake
May 6, 2000
Citations
1
Influential Citations
398
Citations
Quality indicators
Journal
Journal of the American Chemical Society
Abstract
1,2-Bis(2-methyl-5-phenyl-3-thienyl)perfluorocyclopentene (1a) and their derivatives, 1,2-bis(2-methyl-5-p-tolyl-3-thienyl)perfluorocyclopentene (2a) and 1,2-bis(2-methyl-5-p-tert-butylphenyl-3-thienyl)perfluorocyclopentene (3a), were found to undergo reversible photochromic reactions in the single-crystalline phase. Upon irradiation with 366 nm light the single crystals turned blue. The blue colored crystals returned to colorless by irradiation with visible light (λ > 480 nm). The substituents at para positions of the phenyl groups did not affect the rates of photocyclization reactions both in the single-crystalline phase and in hexane. Activation energies of the photocyclization reactions were almost zero. On the other hand, activation energies as much as 5−10 kJ mol-1 were observed in the photocycloreversion reactions in the single-crystalline phase. These values were smaller than those observed in solution, ca. 16 kJ mol-1. Slow thermal cycloreversion reaction of the closed-ring isomer (1b) was observ...