Lan Kai, Zhang Cefei, Li Yifei, Hu Changwei, Su Zhishan, Cheng Chuyang
College of Chemistry, Key Laboratory of Green Chemistry and Technology of Ministry of Education, Sichuan University, Chengdu, Sichuan, 610064, China.
College of Chemistry, Key Laboratory of Green Chemistry and Technology of Ministry of Education, National and Local Joint Engineering Laboratory of Energy Plant Biofuel Preparation and Utilization, Sichuan University, Chengdu, Sichuan, 610064, China.
Angew Chem Int Ed Engl. 2025 Sep 15;64(38):e202507763. doi: 10.1002/anie.202507763. Epub 2025 Aug 4.
Organic molecules exhibiting aggregation-induced emission (AIE) have attracted considerable attention due to their exceptional solid-state luminescent properties. Understanding the AIE mechanism has been a focal point of both theoretical and experimental research. While conical intersection (CI) dynamics on potential energy surfaces (PESs) have emerged as a key factor in elucidating the AIE mechanism, modulating the accessibility to CI to regulate the non-radiative decay pathways remains a substantial challenge. Here we propose a new strategy leveraging strain energy introduced by cycloparaphenylenes (CPPs) to tune the AIE property of tetraphenylethylene (TPE). We synthesized and characterized a series of TPE-incorporated CPPs with varying sizes and endo/exo vinyl moieties. The photophysical properties and AIE behavior of these strained TPE-CPPs were meticulously examined. Endo-TPE-CPPs exhibit AIE, while Exo-TPE-CPPs do not, opposite to strain-free TPE macrocycles. The luminescence of Endo-TPE-CPPs and Exo-TPE-CPPs can be further tuned by adjusting the number of phenylene units in the loop. Their excited-state dynamics were investigated using density functional theory (DFT) calculation and time-resolved absorption spectroscopy. The strain energy induces structural distortion of TPE, stabilizing or elevating the transition state (TS), thereby regulating the accessibility to CI and enabling tunable AIE properties. These findings provide new insights for designing AIE molecules.
具有聚集诱导发光(AIE)特性的有机分子因其优异的固态发光性能而备受关注。理解AIE机制一直是理论和实验研究的重点。虽然势能面(PESs)上的锥形交叉(CI)动力学已成为阐明AIE机制的关键因素,但调节CI的可达性以调控非辐射衰变途径仍然是一项重大挑战。在此,我们提出一种新策略,利用环对亚苯基(CPPs)引入的应变能来调节四苯乙烯(TPE)的AIE性质。我们合成并表征了一系列具有不同尺寸和内/外乙烯基部分的含TPE的CPPs。对这些应变TPE-CPPs的光物理性质和AIE行为进行了细致研究。与无应变的TPE大环相反,内式TPE-CPPs表现出AIE,而外式TPE-CPPs则不表现。通过调整环中苯撑单元的数量,可以进一步调节内式TPE-CPPs和外式TPE-CPPs的发光。利用密度泛函理论(DFT)计算和时间分辨吸收光谱研究了它们的激发态动力学。应变能诱导TPE的结构畸变,稳定或提高过渡态(TS),从而调节CI的可达性并实现可调谐的AIE性质。这些发现为设计AIE分子提供了新的见解。