Yu Wentao, Zhang Han, Yin Ping-An, Zhou Fan, Wang Zhiming, Wu Wanqing, Peng Qian, Jiang Huanfeng, Tang Ben Zhong
Key Laboratory of Functional Molecular Engineering of Guangdong Province, School of Chemistry and Chemical Engineering, South China University of Technology (SCUT), Guangzhou 510640, China.
AIE Institute, SCUT-HKUST Joint Research Institute, Guangzhou International Campus, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, China.
iScience. 2020 Sep 19;23(10):101587. doi: 10.1016/j.isci.2020.101587. eCollection 2020 Oct 23.
The development of aggregation-induced emission (AIE) building block and deciphering its luminescence mechanism are of great significance. Here a feasible strategy for the construction of AIE unit based on - isomerization (EZI) of exocyclic C=N double bond is proposed. Taking [1,2,4]thiadiazole[4,3-]pyridine (TZP) derivative as an example, its aryl-substituted derivative (TZPP) shows obvious AIE character. The analysis of spectral data and theoretical calculations indicates that fast structural relaxation of TZPP in the emissive state plays a key role in a low fluorescence quantum yield in dilute solution, which should be caused by the small energy gap between locally excited (LE) state and twisted intramolecular charge transfer state. When in solid state, the bright emission with LE state characteristic reappears due to the large shift barrier of geometry transformation. As a potential building block for AIEgens with special heterocyclic structure, these findings would open up opportunities for developing various functional materials.
聚集诱导发光（AIE）构建基元的开发及其发光机制的解析具有重要意义。本文提出了一种基于环外C=N双键的 - 异构化（EZI）构建AIE单元的可行策略。以[1,2,4]噻二唑[4,3 - ]吡啶（TZP）衍生物为例，其芳基取代衍生物（TZPP）表现出明显的AIE特性。光谱数据分析和理论计算表明，TZPP在发射态的快速结构弛豫在稀溶液中低荧光量子产率中起关键作用，这应该是由局域激发（LE）态和扭曲分子内电荷转移态之间的小能隙引起的。在固态时，由于几何转变的大位垒，具有LE态特征的明亮发射再次出现。作为具有特殊杂环结构的AIEgens潜在构建基元，这些发现将为开发各种功能材料带来机遇。
