化学学报 ›› 2015, Vol. 73 ›› Issue (8): 819-825.DOI: 10.6023/A15040224 上一篇    下一篇

研究论文

基于六苯基苯骨架四苯基乙烯衍生物的合成及聚集诱导发光性质研究 2016 Awarded

寻知庆, 唐海云, 曾毅, 陈金平, 于天君, 张小辉, 李嫕   

  1. 光化学转换与功能材料重点实验室 中国科学院理化技术研究所 北京 100190
  • 收稿日期:2015-04-02 出版日期:2015-08-14 发布日期:2015-04-30
  • 通讯作者: 曾毅, 李嫕 E-mail:zengyi@mail.ipc.ac.cn;yili@mail.ipc.ac.cn
  • 基金资助:

    项目受科技部国家重点基础研究发展计划(Nos. 2013CB834703, 2013CB834505)和国家自然科学基金(Nos. 21273258, 21233011, 21172229, 21004072)资助.

Synthesis and Aggregation-induced Emission of Tetraphenylethylene Derivatives Based on Hexakisphenylbenzene Backbone

Xun Zhiqing, Tang Haiyun, Zeng Yi, Chen Jinping, Yu Tianjun, Zhang Xiaohui, Li Yi   

  1. Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190
  • Received:2015-04-02 Online:2015-08-14 Published:2015-04-30
  • Supported by:

    Project supported by the 973 Program (Nos. 2013CB834703, 2013CB834505) and the National Natural Science Foundation of China (Nos. 21273258, 21233011, 21172229, 21004072).

设计合成了三个基于六苯基苯骨架结构的四苯基乙烯衍生物HPB-nTPE (n=2, 4, 6), 它们的分解温度均在440 ℃以上, 具有很好的热稳定性. 研究了化合物的均相溶液、聚集体以及固体粉末的光物理性质. 该类化合物具有典型的聚集诱导发光性质, 在均相溶液中几乎不发光, 而形成聚集体后发出明亮的蓝绿色荧光, 荧光量子产率分别为0.37, 0.36和0.37, 与均相溶液中相比增强了400多倍. HPB-nTPE固态呈无定形结构, 荧光量子产率分别为0.39, 0.36和0.36, 约为固态四苯基乙烯的1.8倍. HPB-nTPE的聚集态和固态的高发光量子产率来自两方面的贡献, 一是凝聚态抑制了四苯基乙烯基团中苯环的自由旋转引起的激发态非辐射跃迁, 另一方面是星形刚性六苯基苯骨架进一步抑制了凝聚态分子内和分子间四苯基乙烯基团π-π堆积引起的激发态非辐射跃迁过程, 从而提高了四苯基乙烯基团的辐射跃迁效率. 本研究对高效有机光功能材料的发展有重要意义.

关键词: 四苯基乙烯, 六苯基苯, 聚集诱导发光, 纳米聚集体

A series of tetraphenylethylene (TPE) derivatives based on hexakisphenylbenzene backbone (HPB-nTPE, n=2, 4, 6) were synthesized by cobalt carbonyl-catalyzed cyclotrimerization of alkynes with 1,2-bis(4-(tert-butyl)phenyl)ethyne and 1,2-bis(4'-(1,2,2-triphenylvinyl)-[1,1'-biphenyl]-4-yl)ethyne (TPE-TPE) as starting materials. By varying the ratio of the starting materials, HPB-nTPE (n=2, 4, 6) with 2, 4 or 6 TPE substituents were obtained. The structures of HPB-nTPE (n=2, 4, 6) were characterized by IR, 1H NMR and MALDI-TOF mass spectra. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) show that the decomposition temperatures of HPB-nTPE are all above 440 ℃, indicative of high thermal stability of HPB-nTPE. The photophysical properties of the tetrahydrofuran solution, the aggregate and the neat solid of HPB-nTPE were investigated. The aggregates of HPB-nTPE (n=2, 4, 6) were obtained in tetrahydrofuran/water mixed solvents with various volume fractions of water, which was confirmed by the scanning electron microscope (SEM). HPB-nTPE (n=2, 4, 6) show typical aggregation induced emission properties, almost non-emissive in tetrahydrofuran solution, but strongly emissive in the aggregate or solid state. The highest fluorescence quantum yields for HPB-nTPE (n=2, 4, 6) in aggregate state are 0.37, 0.36 and 0.37, respectively, which are more than 400 times higher than that in tetrahydrofuran. The quantum yields of the neat solid of HPB-nTPE (n=2, 4, 6) are determined to be 0.39, 0.36 and 0.36, which are ca. 1.8 times of that of the neat solid of tetraphenylethylene. Both restrictions of the intramolecular rotation of phenyl rings and the inter/intramolecular π-π stacking of the TPE chromophores caused by the star-shape rigidity structure of hexakisphenylbenzene suppress the nonradiative transition, consequently, giving higher fluorescence quantum yield of the aggregates and the neat solid of HPB-nTPE in comparison with TPE. This work is of importance for developing highly emissive organic materials in solid states.

Key words: tetraphenylethylene, hexakisphenylbenzene, aggregation induced emission, nanoaggregate