Alkyl substituent effects in photochemical and thermal reactions of photochromic thiophene-S,S-dioxidized diarylethenes
作者:Hiroaki Shoji、Daichi Kitagawa、Seiya Kobatake
DOI:10.1039/c3nj01246h
日期:——
photocycloreversion reaction was suppressed by thiophene-oxidation. The diarylethene closed-ring isomers with secondary alkyl groups at the reactive positions were found to undergo thermal bleaching reactions to produce byproducts. The thermal bleaching reactions were accelerated by introducing a more bulky substituent at the reactive positions. The relationship between the rate constant of the thermal
Thermal bleaching reactions of photochromic diarylethenes with thiophene-S,S-dioxide for a light-starting irreversible thermosensor
作者:Hiroaki Shoji、Seiya Kobatake
DOI:10.1039/c3cc00053b
日期:——
Thiophene-S,S-dioxidized diarylethenes introducing bulky substituents at the reactive positions were newly synthesized. The diarylethenes showed reversible photochromism, whereas the photocycloreversion reaction was suppressed by thiophene-oxidation. The diarylethene closed-ring isomers having secondary alkyl groups at the reactive positions were found to undergo thermal bleaching reactions which produce
Diarylperfluorocyclopentenes having 2-isopropyl-5-phenylthiophene and 2-isopropyl-1-benzothiophene aryl groups underwent thermally reversible photochromism in solution. The photogenerated colored closed-ring isomers returned to the initial colorless open-ring isomers above 60 °C. The activation energies of the thermal cycloreversion were estimated to be 118 and 132 kJ/mol for the thiophene and benzothiophene derivatives, respectively.
具有 2-异丙基-5-苯基噻吩和 2-异丙基-1-苯并噻吩芳基的二全氟环戊烯在溶液中发生热可逆光致变色。光生成的有色闭环异构体在 60 °C 以上又返回到最初的无色开环异构体。据估计,噻吩和苯并噻吩衍生物的热环化活化能分别为 118 和 132 kJ/mol。