title: Restriction of intramolecular motions: the general mechanism behind aggregation-induced emission.
abstract: Aggregation-induced emission (AIE) has been harnessed in many systems through the principle of restriction of intramolecular rotations (RIR) based on mechanistic understanding from archetypal AIE molecules such as tetraphenylethene (TPE). However, as the family of AIE-active molecules grows, the RIR model cannot fully explain some AIE phenomena. Here, we report a broadening of the AIE mechanism through analysis of 10,10',11,11'-tetrahydro-5,5'-bidibenzo[a,d][7]annulenylidene (THBDBA), and 5,5'-bidibenzo[a,d][7]annulenylidene (BDBA). Analyses of the computational QM/MM model reveal that the novel mechanism behind the AIE of THBDBA and BDBA is the restriction of intramolecular vibration (RIV). A more generalized mechanistic understanding of AIE results by combining RIR and RIV into the principle of restriction of intramolecular motions (RIM).
authors.affiliation: Department of Chemistry, Institute for Advanced Study, Institute of Molecular Functional Materials, Division of Biomedical Engineering, Division of Life Science and State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon (Hong Kong).
authors.forename: Nelson L C
authors.initials: NL
authors.lastname: Leung
authors.forename: Ni
authors.initials: N
authors.lastname: Xie
authors.forename: Wangzhang
authors.initials: W
authors.lastname: Yuan
authors.forename: Yang
authors.initials: Y
authors.lastname: Liu
authors.forename: Qunyan
authors.initials: Q
authors.lastname: Wu
authors.forename: Qian
authors.initials: Q
authors.lastname: Peng
authors.forename: Qian
authors.initials: Q
authors.lastname: Miao
authors.forename: Jacky W Y
authors.initials: JW
authors.lastname: Lam
authors.forename: Ben Zhong
authors.initials: BZ
authors.lastname: Tang
keywords: aggregation-induced emission; intramolecular motions; intramolecular rotations; intramolecular vibrations; tetraphenylethene