Acta Chim. Sinica ›› 2019, Vol. 77 ›› Issue (8): 735-740.DOI: 10.6023/A19060214 Previous Articles     Next Articles

Article

一个强荧光三维超分子有机框架的构建及其对苦味酸的选择性传感

吴义鹏a, 王泽坤a, 王辉a, 张丹维a, 赵新b, 黎占亭a   

  1. a 复旦大学化学系 上海市分子催化与功能材料重点实验室 上海 200438;
    b 中国科学院上海有机化学研究所 有机功能分子合成与组装化学重点实验室 上海 200032
  • 收稿日期:2019-06-15 出版日期:2019-08-15 发布日期:2019-06-28
  • 通讯作者: 黎占亭, 赵新 E-mail:ztli@fudan.edu.cn;xzhao@sioc.ac.cn
  • 基金资助:

    项目受国家自然科学基金(Nos.21432004,21890732)资助.

Self-Assembly of a Highly Fluorescent Three-Dimensional Supramolecular Organic Framework and Selective Sensing for Picric Acid

Wu Yi-Penga, Wang Ze-Kuna, Wang Huia, Zhang Dan-Weia, Zhao Xinb, Li Zhan-Tinga   

  1. a Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai 200438, China;
    b Key Laboratory of Synthetic and Self-Assembly Chemistry for Organic Functional Molecules, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, China
  • Received:2019-06-15 Online:2019-08-15 Published:2019-06-28
  • Contact: 10.6023/A19060214 E-mail:ztli@fudan.edu.cn;xzhao@sioc.ac.cn
  • Supported by:

    Project supported by the National Natural Science Foundation of China (Nos. 21432004, 21890732).

Cucurbit[8]uril (CB[8])-encapsulation-based host-guest chemistry has been utilized to construct supramolecular organic frameworks, a family of water-soluble, self-assembled periodic porous structures, from multi-armed preorganized building blocks. The tetrahedral prototype building block has been incorporated with four CH2 units to connect the central tetraphenylmethane and appended aromatic arms. Herein we designed and prepared a new fully conjugated tetrahedral building block T-1, which possesses four N-methyl 4-(4-styrylphenyl)pyridinium (SPP) arms. The 1:2 mixture of T-1 with CB[8] in water leads to the formation of a new three-dimensional homogeneous diamondoid supramolecular organic framework SOF-r-SPP through CB[8] encapsulation for intermolecular dimers of the appended SPP units. 1H NMR, absorption and fluorescence experiments conformed strong binding between the two components at diluted concentrations and 1:2 binding stoichiometry. Isothermal calorimetric (ITC) experiments established that the three-component (SPP)2ÌCB[8] complexes formed between the SPP units of T-1 and CB[8] had an apparent binding constant of 5.5×1013 M-2, which was 5.5×104 times as high as that of the complex of a SPP control. ITC experiments also revealed that the self-assembly of SOF-r-SPP are driven both enthalpically and entropically, but the enthalpic contribution was overwhelmingly higher. Dynamic light scattering experiments revealed that within the concentration range of 0.031 mmol/L to 1.0 mmol/L of T-1, the framework possessed a hydrodynamic diameter of 41 nm to 68 nm. Molecular modelling study indicated that the new regular framework formed an aperture of 2.3 nm. Although T-1 has nearly no fluorescence, SOF-r-SPP exhibits strong fluorescence in water probably due to the encapsulation of the SPP dimers by CB[8] that suppresses the relative rotation of the aromatic rings. Adding nitrobenzene or naphthalene derivatives to the solution of SOF-r-SPP remarkably quenched the fluorescence of the framework. Among other sixteen nitro-bearing aromatic molecules, picric acid (2,4,6-trinitrophenol) exhibited the largest quenching ability. At the low concentration of 1.0 μmol/L for T-1 of SOF-r-SPP, 0.1 μmol/L of 2,4,6-tirnitrophenol could cause 16% quenching of the fluorescence of SOF-r-SPP and 0.1 mmol/L of 2,4,6-tirnitrophenol could realize nearly complete quench (>97%). Following a reported method, the limit of detection of SOF-r-SPP for picric acid was as low as 0.024 μmol/L.

Key words: supramolecular organic framework, fluorescence sensing, 2,4,6-trinitrophenol, cucurbituril, self-assembly