期刊
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
卷 2010, 期 9, 页码 1704-1710出版社
WILEY-V C H VERLAG GMBH
DOI: 10.1002/ejoc.200901361
关键词
Molecular recognition; Thermodynamics; Lower-rim substitution; Calixarenes
资金
- 973 Program [2006CB932900]
- National Natural Science Foundation of China [20673061, 20721062, 20703025]
- Deutsche Forschungsgemeinschaft (DFG) [NA-686/5-1]
- Fonds der Chemischen Industrie
- Robert Bosch Foundation
The complex stability constants (K-S) and thermodynamic parameters (Delta H degrees and T Delta S degrees) for the 1:1 complexation of two water-soluble calixarenes, p-sulfonatocalix[4]arene (SC4A) and 5,11,17,23-tetrasulfonato-25,26,27,28-tetrakis(n-butyl)calix[4]arene (SC4A-Bu), with organic ammonium cations and neutral spherical organic molecules, have been determined by means of isothermal titration calorimetry (ITC) in aqueous solutions at 298.15 K. The obtained results indicate that, upon complexation with these guests by SC4A-Bu, the enthalpy changes become less favorable, whereas the entropy changes become more favorable relative to SC4A complexation. These differences can be attributed to differential degrees of desolvation and removal of high-energy water as well as the change in conformation or conformational degrees of freedom upon complexation. The calorimetric investigations, accompanied by H-1 NMR and UV/Vis spectroscopy and X-ray crystallography provide a thermodynamic explanation for the different complexation behavior of SC4A and SC4A-Bu towards charged and neutral organic guests. Binding ability and molecular selectivity are discussed from the viewpoint of the conformational geometry and electronic properties of hosts and guests.
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。
推荐
暂无数据