title: Aggregation-induced emission enhancement of 2-(2'-hydroxyphenyl)benzothiazole-based excited-state intramolecular proton-transfer compounds.
abstract: A novel class of 2-(2'-hydroxyphenyl)benzothiazole-based (HBT-based) excited-state intramolecular proton-transfer (ESIPT) compounds, N,N'-di[3-Hydroxy-4-(2'-benzothiazole)phenyl]isophthalic amide (DHIA) and N,N'-di[3-Hydroxy-4-(2'-benzothiazole)phenyl]5-tert-butyl-isophthalic amide (DHBIA) has been feasibly synthesized and the properties of their nanoparticles in THF/H2O mixed solvent were investigated. Both compounds were found to exhibit aggregation-induced emission enhancement (AIEE) due to restricted intramolecular motion and easier intramolecular proton transfer in solid state. On identical experimental conditions, the emission of DHBIA aggregates increased more remarkably than that of DHIA. Different aggregation forms of these two organic compounds, due to the steric hindrance of a single tert-butyl group, could be responsible for the notably different degrees of the fluorescence enhancement. Their aggregation modes were investigated on the basis of time-dependent absorption, scanning electron microscope (SEM) images, and molecular modeling with theoretical calculation. The photophysical dynamics were also depicted based on the extremely fast ESIPT four-level cycle.
authors.affiliation: Beijing National Laboratory for Molecular Sciences, Key Laboratory of Photochemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Qian
authors.forename: Shayu
authors.initials: S
authors.lastname: Li
authors.forename: Guoqi
authors.initials: G
authors.lastname: Zhang
authors.forename: Qian
authors.initials: Q
authors.lastname: Wang
authors.forename: Shuangqing
authors.initials: S
authors.lastname: Wang
authors.forename: Huijun
authors.initials: H
authors.lastname: Xu
authors.forename: Chengzhang
authors.initials: C
authors.lastname: Li
authors.forename: Yi
authors.initials: Y
authors.lastname: Li
authors.forename: Guoqiang
authors.initials: G
authors.lastname: Yang