Photochromism of diarylethenes having thiophene oligomers as the aryl groups
摘要:
Diarylperfluorocyclopentenes having thiophene oligomers as the aryl groups were synthesized and their photochromic reactivity was examined. The cylization quantum yields were scarcely affected by the oligomer chain length, while the ring-opening quantum yields dramatically decreased with the increasing number of the thiophene rings, The low quantum yield of a 1,2-bis(5 ''-cyano-2,4-dimethyl-5,2':5',2 ''-terthiophen-3-yl)perfluorocyclopentene closed-ring form was increased as large as 34 times by raising the reaction temperature from 25 degrees C to 150 degrees C. (C) 1997 Elsevier Science Ltd.
Photochromism of diarylethenes having thiophene oligomers as the aryl groups
摘要:
Diarylperfluorocyclopentenes having thiophene oligomers as the aryl groups were synthesized and their photochromic reactivity was examined. The cylization quantum yields were scarcely affected by the oligomer chain length, while the ring-opening quantum yields dramatically decreased with the increasing number of the thiophene rings, The low quantum yield of a 1,2-bis(5 ''-cyano-2,4-dimethyl-5,2':5',2 ''-terthiophen-3-yl)perfluorocyclopentene closed-ring form was increased as large as 34 times by raising the reaction temperature from 25 degrees C to 150 degrees C. (C) 1997 Elsevier Science Ltd.
Femtosecond Spectroscopic Study on Photochromic Diarylethenes with Terthiophene
作者:N. Ohtaka、Y. Hase、K. Uchida、M. Irie、N. Tamai
DOI:10.1080/10587250008023818
日期:2000.6.1
Photochromic ring-closure reactions of diarylethene derivatives with terthiophene (T3H, T3Me) have been examined by femtosecond transient absorption spectroscopy. The rate of the ring-closure reaction of T3H in n-hexane was estimated to be similar to 2.5 ps, which is very similar to that of T3Me in the same solvent. It was suggested that the ring-closure reaction proceeds through a concerted mechanism without any intermediates but not a two-step mechanism. The rate of ring-closure reaction was also dependent on the solvent polarity, suggesting that the charge transfer state in the excited singlet state plays an important role in the photochromic reaction.
Photochromism of diarylethenes having thiophene oligomers as the aryl groups
Diarylperfluorocyclopentenes having thiophene oligomers as the aryl groups were synthesized and their photochromic reactivity was examined. The cylization quantum yields were scarcely affected by the oligomer chain length, while the ring-opening quantum yields dramatically decreased with the increasing number of the thiophene rings, The low quantum yield of a 1,2-bis(5 ''-cyano-2,4-dimethyl-5,2':5',2 ''-terthiophen-3-yl)perfluorocyclopentene closed-ring form was increased as large as 34 times by raising the reaction temperature from 25 degrees C to 150 degrees C. (C) 1997 Elsevier Science Ltd.