Chemical Research in Chinese Universities ›› 2021, Vol. 37 ›› Issue (1): 1-15.doi: 10.1007/s40242-021-0381-6

• Reviews •     Next Articles

Restriction of Intramolecular Motion(RIM): Investigating AIE Mechanism from Experimental and Theoretical Studies

ZHANG Jianyu1, ZHANG Haoke2, LAM Jacky W. Y.1, TANG Ben Zhong1,2,3,4   

  1. 1. Department of Chemistry, Hong Kong Branch of Chinese National Engineering Research Centre for Tissue Restoration and Reconstruction, Institute for Advanced Study, and Department of Chemical and Biological Engineering, The Hong Kong University of Science & Technology, Clear Water Bay, Kowloon, Hong Kong, P. R. China;
    2. MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027, P. R. China;
    3. Center for Aggregation-Induced Emission, SCUT-HKUST Joint Research Institute, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, P. R. China;
    4. AIE Institute, Guangzhou Development District, Guangzhou 510530, P. R. China
  • Received:2020-11-21 Revised:2020-12-13 Online:2021-02-01 Published:2021-02-03
  • Contact: ZHANG Haoke, TANG Ben Zhong E-mail:zhanghaoke@zju.edu.cn;tangbenz@ust.hk
  • Supported by:
    This work is supported by the National Natural Science Foundation of China (No.21788102), the Research Grants of Council of Hong Kong, China (Nos.16304819, 16305618, N_HKUST609/19, C6009-17G) and the Innovation of Technology Commission of Hong Kong, China(No.ITC-CNERC14SC01).

Abstract: Mechanistic studies promote scientific development from phenomena to theories. Aggregation-induced emission(AIE), as an unusual photophysical phenomenon, builds the bridge between molecular science and aggregate mesoscience. With the twenty-year development of AIE, restriction of intramolecular motion(RIM) has been verified as the working mechanism of AIE effect. In this review, these mechanistic works about RIM are summarized from experimental and theoretical perspectives. Thereinto, the experimental studies are introduced from three parts:external rigidification, structural modification and structural characterization. In the theoretical part, calculations on the low-frequency motion of AIEgens have been performed to prove the RIM mechanism. By virtue of the theoretical calculations, some new mechanisms are proposed to supplement the RIM, such as restriction of access to conical intersection, suppression of Kasha transition, restriction of access to dark state, etc. It is foreseeable that the RIM mechanism will unify the photophysical theories for both molecules and aggregates, and inspire more progress in aggregate science.

Key words: Aggregation-induced emission(AIE), Restriction of intramolecular motion, Photophysical mechanism, Aggregate science