Photochromism of Thiazole‐Containing Triangle Terarylenes
Photochromism of Thiazole‐Containing Triangle Terarylenes
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DOI：
10.1002/ejoc.200700074
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发表时间：
2007-07
影响因子：
2.8
通讯作者：
T. Nakashima;K. Atsumi;Shigekazu Kawai;Tetsuya Nakagawa;Y. Hasegawa;T. Kawai
中科院分区：
文献类型：
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作者：
T. Nakashima;K. Atsumi;Shigekazu Kawai;Tetsuya Nakagawa;Y. Hasegawa;T. Kawai
合成了基于4,5-二芳基噻唑结构的三角萜烯衍生物，并对其在溶液和结晶状态下的光致变色性能进行了研究。噻唑基取代的terarylenes在溶液中表现出可逆的光致变色，其光环化量子产率高达60%，而4,5-二噻唑基噻唑衍生物即使在单晶状态下也会发生光致变色反应，而4,5-二噻唑基噻唑（terthiazole）在结晶状态下不发生光致变色反应。通过x射线晶体分析发现，4,5-二噻唑基噻唑和4,5-二噻唑基噻唑的光致变色反应性差异是由于晶体形态的差异造成的。测定了噻唑基取代的苯乙烯和相应的噻吩衍生物在溶液中的热循环还原活化能。光生闭环异构体向开环异构体转变的活化能随着噻唑取代噻吩的次数增加而增加。噻唑的芳烃稳定能比噻吩低，这被认为是噻唑基取代的对苯乙烯闭环异构体热稳定性的原因。（©Wiley-VCH Verlag GmbH & Co. KGaA，德国Weinheim 69451, 2007）
Triangle terarylene derivatives based on the 4,5-diarylthiazole structure have been synthesized and their photochromic properties have been studied both in solution and in the crystalline state. The thiazolyl-substituted terarylenes displayed reversible photochromism in solution, with photocyclization quantum yields as high as 60 %, while a 4,5-dithienylthiazole derivative underwent photochromic reaction even in the single-crystal state, although a 4,5-dithiazolylthiazole (terthiazole) showed no photochromic reaction in the crystalline phase. The difference in photochromic reactivity between the 4,5-dithienylthiazole and the 4,5-dithiazolylthiazole was found by X-ray crystallographic analyses to originate from conformational differences in the crystalline state. The thermal cycloreversion activation energies in the solution phase were measured for thiazolyl-substituted terarylenes and for a corresponding terthiophene derivative. The activation energy for the transition from photogenerated closed-ring isomer to open-ring isomer increased with the number of substitutions of thiazole unit for thiophene. The lower aromatic stabilization energy of thiazole in relation to that of thiophene was considered to be responsible for the thermal stability of the closed-ring isomers of thiazolyl-substituted terarylenes.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)