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
Photocyclization and photocycloreversion quantum yields of three diarylethene derivatives were determined in the single-crystalline phase. The former yields in the crystalline phase were twice as large as those in solution. This can be attributed to only photoreactive antiparallel conformers being packed in the crystals, while in solution both photoreactive antiparallel and photoinactive parallel conformers coexist in almost equal amounts. The quantum yields in the crystals were found to be extremely high and 1,2-bis(2-ethyl-5-phenyl3 -thienyl)perfluorocyclopentene (3a) exhibited the quantum yield of unity (100%). The latter yield of the closed-ring isomer of 1,2-bis(2,5-dimethyl-3-thienyl)perfluorocyclopentene (1a) was similar to that in solution, while the yields of the closed-ring isomers of 1,2-bis(2,4-dimethyl-5-phenyl-3-thienyl)perfluorocyclopentene (2a) and 3a were higher than those in solution by a factor of 2 to 3. The high yields are attributable to the constrained conformation of the photogenerated closed-ring isomers in the crystal lattice.
Photochromic fluorescent diarylethene nanocrystals grown in sol–gel thin films
作者:Nathalie Sanz-Menez、Virginie Monnier、Isabelle Colombier、Patrice L. Baldeck、Masahiro Irie、Alain Ibanez
DOI:10.1016/j.dyepig.2010.03.017
日期:2011.6
Nanocrystals of two diarylethene compounds, 1,2-bis(2-ethyl-5-phenyl-3-thienyl)perfluorocyclopentene (D1) and 1,2-bis(3-methyl-2-thienyl)ethene (D2), were grown in sol gel thin films and their optical properties (fluorescence and photo-conversion) were compared to that of diarylethene microcrystals. (C) 2010 Elsevier Ltd. All rights reserved.
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