Acta Chimica Sinica ›› 2014, Vol. 72 ›› Issue (4): 447-455.DOI: 10.6023/A14010029 Previous Articles     Next Articles



周丽a, 徐立进a, 龚汉元b   

  1. a 中国人民大学化学系 北京 100872;
    b 北京师范大学化学学院 北京 100875
  • 投稿日期:2014-01-10 发布日期:2014-02-06
  • 通讯作者: 徐立进;龚汉元;
  • 基金资助:


Pattern and Protonation Effect of Benzene Dicarboxylate Anion Species in Self-assembly System

Zhou Lia, Xu Lijina, Gong Hanyuanb   

  1. a Department of Chemistry, Renmin University of China, Beijing 100872;
    b College of Chemistry, Beijing Normal University, Beijing 100875
  • Received:2014-01-10 Published:2014-02-06
  • Supported by:

    Project supported by the National Natural Science Foundation of China (Nos. 21202199, 21372258).

A novel macrocycle host with flexible structure and big cavity, cyclo[2](2,6-bis(1H-imidazol-1-yl)- pyridine)[2](1,4-dimethylenebenzene) (i.e. 14+), was effectively synthesized through cyclization reaction between 1,4-bisbromo-methylbenzene and 2,6-di(1H-imidazol-1-yl)pyridine. The binding and self-assembly properties of macrocycle host 14+ with a series of benzene dicarboxylate anion guests (i.e. mono-terephthalate anion 2, di-terephthalate anion 3, mono-isophthalate anion 4, di-isophthalate anion 5, mono-phthalate anion 6 or di-phthalate anion 7) were studied in detail via 1H NMR spectroscopy, diffusion ordered NMR spectroscopy (DOSY), nuclear Overhauser effect spectroscopy (NOESY) in solution, electrospray ionization mass spectrometry (ESI-MS) in gas phase, and X-ray single crystallography in solid state. The result implied that macrocycle host 14+ and mono-terephthalate anion (2) or di-isophthalate anion (5) form pseudorotaxane structure, even more complex supramolecular self-assembly structure (e.g. pseudo-oligarotaxne ). Meanwhile the other guest anions adopt the "outside" binding modes in the complexation with 14+. It is also found that the thermodynamic equilibrium(s) and association constants of the complexes between macrocycle host 14+ and a series of benzene dicarboxylate anion guest species are different via 1H NMR Job-plots and 1H NMR spectroscopic titrations in solution: (1) the stoichiometry values suggested that host 14+ can bind equivalent or more mono-anion guests than di-anion species from the same benzene dicarboxylic acid; (2) comparing the association constants of 1:1 (host:guest) complex between 14+ and mono-anion species resulted in Ka[14+·2]>Ka[14+·4]>Ka[14+·6]; the similar comparison was carried out for di-anion species interactions and obtained Ka[14+·3]>Ka[14+·5]>Ka[14+·7]; the result suggest that the pattern of the anion highly influences the thermostability of the 1:1 complex. It is speculated that the pattern and protonation factors of the benzene dicarboxylate anion guests determine their interactions with macrocycle 14+, including binding modes, stoichiometries, association constants, and so on. The finding will help to direct the following novel supramolecular self-assembly construction involving macrocycle host and multi-carboxylate anion species.

Key words: macrocylic host compound, benzene dicarboxylate anions, host-guest chemistry, non-covalent weak interactions, complexation mode