Xie Hui-Ming, Li Shao-Ju, Zhang Pan-Yi, Feng Jiao, Li Shayu, Yang Guoqiang
College of Chemistry and Chemical Engineering & Chongqing Key Laboratory of Theoretical and Computational Chemistry , Chongqing University , Chongqing 401331 , PR China.
Institute of Chemistry & University of Chinese Academy of Sciences , Chinese Academy of Sciences , Beijing 100190 , PR China.
J Phys Chem A. 2020 Feb 6;124(5):889-897. doi: 10.1021/acs.jpca.9b09834. Epub 2020 Jan 23.
The organic fluorescent probes for temperature have received increasing interest due to their extremely high spatial and temporal resolution. A few of triarylboron derivatives, as almost the only molecular probes consisting of a single luminophore, have the ability to change their luminescent color at different temperatures. The mechanism of their luminescence thermochromism is controversial. Herein, several spectral experiments, along with time-dependent density functional theory (TDDFT) and coupled-cluster (CC) calculations, are carried out to elucidate the temperature-dependent luminescence. The CC rather than the TDDFT methods give a relatively reasonable explanation for the experimental results. Consequently, the thermochromism is now considered as the result of conformational thermal equilibria that occur in both the excited and ground states. Besides, an unusual conformer with intramolecular excimer characteristic plays a crucial role in the attractive luminescence behavior.
由于具有极高的空间和时间分辨率，有机温度荧光探针受到了越来越多的关注。作为几乎唯一由单个发光体组成的分子探针，一些三芳基硼衍生物能够在不同温度下改变其发光颜色。其发光热致变色机制存在争议。在此，进行了几项光谱实验，并结合含时密度泛函理论（TDDFT）和耦合簇（CC）计算来阐明温度依赖性发光。CC方法而非TDDFT方法对实验结果给出了相对合理的解释。因此，现在认为热致变色是激发态和基态中构象热平衡的结果。此外，一种具有分子内激基缔合物特征的异常构象体在这种引人注目的发光行为中起着关键作用。
