Photochromism of 1,2-bis(2-methyl-5-phenyl-3-thienyl)perfluorocyclopentene in a single-crystalline phase

被引:466
作者
Irie, M
Lifka, T
Kobatake, S
Kato, N
机构
[1] Kyushu Univ, Grad Sch Engn, Dept Chem & Biochem, Higashi Ku, Fukuoka 8128581, Japan
[2] Japan Sci & Technol Corp, CREST, Higashi Ku, Fukuoka 8128581, Japan
[3] Kyushu Univ, Inst Adv Mat Study, Kasuga, Fukuoka 8168580, Japan
关键词
D O I
10.1021/ja993181h
中图分类号
O6 [化学];
学科分类号
0703 ;
摘要
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 (lambda > 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 observed above 150 degrees C. The activation energy was 139 kJ mol(-1).
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页码:4871 / 4876
页数:6
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