Cho Yang-Jin, Kim So-Yoen, Lee Jie-Won, Han Won-Sik, Kim Chul Hoon, Son Ho-Jin, Kang Sang Ook
Department of Advanced Materials Chemistry, Korea University, Sejong, 30019, South Korea.
Department of Chemistry, Seoul Women's University, Seoul, 01797, South Korea.
Chemistry. 2019 Jun 18;25(34):8149-8156. doi: 10.1002/chem.201901305. Epub 2019 May 17.
A new type of solid-state photochromism was observed in an AB -type molecular assembly comprising a central silole and two peripheral o-carborane units, and in this assembly, depending on the assembling positions of those units at the adjoining benzene ring, two different regioisomers were formed: Si-m-Cb and Si-p-Cb. Each isomer showed different solid-state photochromism depending on its solid-state molecular conformation and was either in the crystalline or amorphous state. The crystals of each meta- or para-isomer, C or C , showed yellow or blue emission, and mechanically grinding those crystals into amorphous powders of A and A , switched their emissions to blue and yellow, respectively. Photophysical studies revealed that the electronic interaction between silole and o-carborane units determined the emission color. The crystal and DFT-optimized structures each account for the crystalline and amorphous structures, respectively, and are correlated well with the electronic interactions in the molecular assembly in the solid state, thus enabling the prediction of the solid-state molecular conformational change.
在一种由中心硅杂环戊二烯和两个外围邻碳硼烷单元组成的AB型分子组装体中观察到了一种新型的固态光致变色现象。在该组装体中，根据这些单元在相邻苯环上的组装位置，形成了两种不同的区域异构体：Si-m-Cb和Si-p-Cb。每种异构体根据其固态分子构象表现出不同的固态光致变色现象，并且处于结晶态或非晶态。每种间位或对位异构体的晶体C或C分别发出黄色或蓝色光，将这些晶体机械研磨成非晶态粉末A和A时，它们的发射光分别变为蓝色和黄色。光物理研究表明，硅杂环戊二烯和邻碳硼烷单元之间的电子相互作用决定了发射颜色。晶体结构和DFT优化结构分别对应结晶态和非晶态结构，并且与固态分子组装体中的电子相互作用密切相关，从而能够预测固态分子构象变化。
