Synthesis of Fluorene-Bridged Arylene Vinylene Fluorophores: Effects of End-Capping Groups on the Optical Properties, Aggregation Induced Emission
Synthesis of Fluorene-Bridged Arylene Vinylene Fluorophores: Effects of End-Capping Groups on the Optical Properties, Aggregation Induced Emission作者机构:Wuhan National Laboratory for Optoelectronics School of Optical and Electronic Information Huazhong University of Science and Technology Wuhan Hubei 430074 China Department of Chemistry Durham University South Road Durham DH1 3LE UK Key Laboratory of Pesticide and Chemical Biology of Ministry of Education College of Chemistry Central China Normal University Wuhan Hubei 430079 China
出 版 物:《Chinese Journal of Chemistry》 (中国化学(英文版))
年 卷 期:2015年第33卷第8期
页 面:939-947页
核心收录:
学科分类:081702[工学-化学工艺] 08[工学] 0817[工学-化学工程与技术] 0803[工学-光学工程]
基 金:国家自然科学基金 国家973计划 M.P.A. acknowledges the NSFC Research Fellowship for International Young Scientists the Key Fellowship of China Post-doctoral Science Foundation
主 题:aggregation-induced emission fluorene triphenylethene tetraphenylethene 2,3,3-triphenylacrylonitrile
摘 要:We have synthesized a series of fluorene-based fluorophores, in which a central fluorene core has been modified with different peripheral arylene vinylene substituents that are able to activate aggregation-induced emission (AIE) characteristics. 9,9-Dioctylfluorene doubly end-capped at the 2,7-positions with triphenylethene groups, such as 4-(2,2-diphenylvinyl)phenyl (F1-(2,2)-HTPE) and 4-(1,2-dipbenylvinyl)phenyl (F1-(1,2)-HTPE) were synthesized and compared to the tetraphenylethene analogue (F1-TPE). Both FI-(2,2)-HTPE and F1-(1,2)-HTPE glow with a deep blue fluorescence in THF solution with emission maxima (λem) of 426 and 403 nm, respectively. The λem slightly red-shifts in the solid-state to 458 nm for F 1-(2,2)-HTPE and 437 nm for F 1-(1,2)-HTPE. The fluorescence quantum yields (ΦF) of F1-(2,2)-HTPE (ΦF=35.1%) and FI-(1,2)-HTPE (ΦF=26.2%) were found to be higher in solution compared to the near quenching of F 1-TPE (ΦF = 0.1%). Consequently, this results in weaker AIE-stability of F1-(2,2)-HTPE (αAIE= 1.5) and F1-(1,2)-HTPE (αAIE=1.9) compared to F1-TPE (αAIE=125), suggesting that four phenyl groups are necessary for efficient AIE-activity of these fluorene bridged arylene vinylene type materials In addition, decreasing the steric hindrance around the arylene vinylene moiety by removal of a phenyl ring is an- other method to decrease the AIE characteristics, in a similar manner to the commonly known "phenyl-locking". Non-polar triphenylethenes are poorer AlE materials than their tetraphenylethene analogues. Replacing the hydro- gen atom of F1-(2,2)-HTPE with a cyano group affords fluorene end-capped with 2,3,3-triphenylacrylonitrile (F1-TPAN), which boosts the AIE-effect to αAIE=90.5 and red-shifts the solid-state emission (λem=528 nm) with near quenching in THF solution (ΦF= 0.12%). X-ray crystallographic analysis of F1-TPAN indicates that the intro- duction of cyano groups can not only diminish the intramolecular steric hindrance in comparison of F1-TPE, but