作者:Taro Yamada、Seiya Kobatake、Masahiro Irie
DOI:10.1246/bcsj.75.167
日期:2002.1
Crystal structures of 1,2-bis(2,4-dimethyl-3-thienyl)perfluorocyclopentene 1a, 1,2-bis(2,4,5-trimethyl-3-thieny)per-fluorocyclopentene 2a and their mixture were determined by X-ray crystal structure analysis and their photochromic reactivities were compared. In the crystal of 1a, 17 mol% of molecules adopted a photoactive anti-parallel conformation and underwent photochromism. The crystal of 2a was not photochromic, because the dithienylethenes are packed in a photochemically inactive anti-parallel conformation. In the co-crystal of 1a and 2a, 2a adopted a photoactive anti-parallel conformation and the ratio of molecules in a photoactive conformation increased to 27 mol%. In the co-crystal, the spectrum of the closed-ring form isomers, 1b and 2b, generated by UV irradiation was broader and blue-shifted by ca. 10 nm in comparison with that of the 1a homocrystal.
通过 X 射线晶体结构分析确定了 1,2-双(2,4-二甲基-3-噻吩基)全氟环戊烯 1a、1,2-双(2,4,5-三甲基-3-噻吩基)全氟环戊烯 2a 及其混合物的晶体结构,并比较了它们的光致变色反应活性。在 1a 的晶体中,17 摩尔%的分子采用了光活性反平行构象并发生了光致变色。2a 的晶体不具有光致变色性,因为二噻吩以光化学性质不活跃的反平行构象排列。在 1a 和 2a 的共晶体中,2a 采用了具有光活性的反平行构象,具有光活性构象的分子比例增加到 27 摩尔%。在共晶体中,紫外线照射产生的闭环异构体 1b 和 2b 的光谱更宽,与 1a 同晶相比蓝移约 10 纳米。