Zhang Tian, Peng Qian, Quan Changyun, Nie Han, Niu Yingli, Xie Yujun, Zhao Zujin, Tang Ben Zhong, Shuai Zhigang
Key Laboratory of Organic OptoElectronics and Molecular Engineering , Department of Chemistry , Tsinghua University , Beijing , 100084 , China . Email:
Key Laboratory of Organic Solids , Beijing National Laboratory for Molecular Science (BNLMS) , Institute of Chemistry , Chinese Academy of Sciences , Beijing , 100190 , China . Email:
Chem Sci. 2016 Aug 1;7(8):5573-5580. doi: 10.1039/c6sc00839a. Epub 2016 May 11.
Aggregation-induced emission (AIE) has become a hot topic for a variety of potential applications, but the understanding of its working mechanism is still under scrutiny. Herein, we proposed the use of the isotope effect (IE) to identify the AIE mechanism: under the restriction of an internal motion mechanism, the IE is pronouncedly different in excited-state decay rates when contrasting AIE luminogens (AIEgens) and non-AIEgens in theoretical calculations. For the complete deuteration of AIEgens, the IE of nonradiative decay rate in solution (<-10%) is much weaker than that (-65% to -95%) in aggregate, because the former stems from the overall results of competitive vibronic coupling and the severe mixing of low-frequency modes while the latter mainly comes from the vibronic coupling only. The experimental results confirm the isotopic "jump" behaviors in AIEgens well. However, non-AIEgens exhibit equivalent IEs (-40% to -90%) in both solution and solid phases. Further partial deuteration schemes for the 6-ring AIE analogues show positional dependence.
聚集诱导发光（AIE）已成为各种潜在应用的热门话题，但其作用机制仍在研究之中。在此，我们提出利用同位素效应（IE）来确定AIE机制：在内部运动机制的限制下，在理论计算中对比AIE发光体（AIEgens）和非AIEgens时，激发态衰减率的同位素效应有显著差异。对于AIEgens的完全氘代，溶液中非辐射衰减率的同位素效应（<-10%）比聚集体中的同位素效应（-65%至-95%）弱得多，因为前者源于竞争振动耦合的总体结果以及低频模式的严重混合，而后者主要仅来自振动耦合。实验结果很好地证实了AIEgens中的同位素“跳跃”行为。然而，非AIEgens在溶液和固相中的同位素效应相当（-40%至-90%）。六环AIE类似物的进一步部分氘代方案显示出位置依赖性。
