4.7 Article

Complexation of 1,4-Bis(pyridinium)butanes by Negatively Charged Carboxylatopillar[5]arene

期刊

JOURNAL OF ORGANIC CHEMISTRY
卷 76, 期 20, 页码 8458-8465

出版社

AMER CHEMICAL SOC
DOI: 10.1021/jo201185e

关键词

-

资金

  1. National Natural Science Foundation of China [20902057, 21002061, 20872087]
  2. Shanghai Municipal Education Commission [J50101]
  3. Shanghai University

向作者/读者索取更多资源

The binding behavior of substituted 1,4-bis(pyridinium)butane derivatives (X-Py(CH2)(4)Py-X, X = H, 2-methyl, 3-methyl, 4-methyl, 2,6-dimethyl, 4-pyridyl, and 4-COOEthyl) 1(2+)-7(2+), with negatively charged carboxylatopillar[5]arene (CP5A) has been comprehensively investigated by H-1 NMR and 2D ROESY and UV absorption and fluorescence spectroscopy in aqueous phosphate buffer solution (pH 7.2). The results indicated that the position of the substituents attached on pyridinium ring dramatically affects the association constants and binding modes. 3- and 4-Substituted guests (1(2+), 3(2+), 4(2+), 6(2+), 7(2+)) form [2]pseudorotaxane geometries with CP5A host, giving very large association constants (>10(5) M-1), while 2,6-dimethyl-substituted 5(2+) forms external complex with relatively small K-a values [(2.4 +/- 0.3) x 10(3) M-1] because the 2,6-dimethylpyridinium unit is too bulky to thread the host cavity. Both of the binding geometries mentioned above are observed for 2(2+), having one methyl group in the 2-position of pyridinium. Typically, the association constant of [2]pseudorotaxane 1(2+)subset of CP5A exceeds 10(6) M-1 water, which is significantly higher than those of previously reported analogues in organic solvents. The remarkably improved complexation of bis(pyridinium) guests by the anionic host was due to electrostatic attraction forces and hydrophobic interactions.

作者

我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。

评论

主要评分

4.7
评分不足

次要评分

新颖性
-
重要性
-
科学严谨性
-
评价这篇论文

推荐

暂无数据
暂无数据