Liu Yingjie, Li Aisen, Xu Shuping, Xu Weiqing, Liu Yu, Tian Wenjing, Xu Bin
State Key Laboratory of Supramolecular Structure and Materials, Institute of Theoretical Chemistry, Jilin University, Qianjin Street No. 2699, Changchun, 130012, China.
Angew Chem Int Ed Engl. 2020 Aug 24;59(35):15098-15103. doi: 10.1002/anie.202002220. Epub 2020 May 14.
A luminescent cocrystal system is reported to undergo crystal-to-crystal phase transformation from yellow-emitting polymorph I to green-emitting polymorph II, triggered by THF fuming or heating, and the green emission can recover to the initial yellow emission by grinding. The established spectroscopic and crystallographic analyses demonstrate that the phase transition occurred and benefits from the combined effect of similar molecular arrange sequence and unique alteration of intermolecular interactions from halogen/hydrogen bonds in I to π-π stacking in II. Furthermore, I and II exhibit red-shift emission under hydrostatic pressure. The emission of I and II shows a red-shift and recovers towards the initial emission upon acid-base fuming. This is a rare example of reversible luminescent switching of cocrystal based upon crystal-to-crystal phase transition, and provides an alternative strategy to develop multi-stimuli responsive materials.
据报道，一种发光共晶体系会经历从发射黄光的多晶型物I到发射绿光的多晶型物II的晶型转变，该转变由四氢呋喃熏蒸或加热引发，且通过研磨，绿色发射可恢复到初始的黄色发射。已建立的光谱和晶体学分析表明，相变发生了，且得益于相似分子排列顺序以及分子间相互作用从I中的卤素/氢键到II中的π-π堆积的独特变化的综合作用。此外，I和II在静水压力下呈现红移发射。I和II的发射在酸碱熏蒸时显示红移并恢复到初始发射。这是基于晶型转变的共晶可逆发光切换的罕见例子，并为开发多刺激响应材料提供了一种替代策略。
