Calorimetric analysis of the 1:1 complexes formed between a water-soluble deep-cavity cavitand, and cyclic and acyclic carboxylic acids
Calorimetric analysis of the 1:1 complexes formed between a water-soluble deep-cavity cavitand, and cyclic and acyclic carboxylic acids
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DOI：
10.1080/10610270701744302
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发表时间：
2008-01-01
影响因子：
3.3
通讯作者：
Gibb, Bruce C.
中科院分区：
文献类型：
--
作者：
Sun, Hao;Gibb, Corinne L. D.;Gibb, Bruce C.
一种水溶性的空穴与一系列无环和环状脂肪族羧酸形成1：1的络合物。用等温滴定量热法测定了不同络合物的标准摩尔热变(增量H度)和结合常数(K-a)，进而测定了不同络合物的吉布斯自由能(增量G度)和熵(增量S度)的变化。热力学测定是在288-318K之间进行的，从而也可以得到标准摩尔热容变化(C-p度)。在疏水效应驱动的典型过程中，观察到C-p增量与客体的可达(非极性)表面积成正比。环状客体和非环状客体表现出相反的趋势；结合时的热容损失随着脂肪链的增加而增加，而环状客体则相反。
A water-soluble cavitand was shown to form 1:1 complexes with a series of acyclic and cyclic aliphatic carboxylic acids. Isothermal titration calorimetry was used to determine the standard molar enthalpy change (Delta H degrees) and binding constant (K-a), and hence the Gibbs free energy (Delta G degrees) and entropy (Delta S degrees) change for the different complexes. The thermodynamic determinations were carried out from 288 to 318K, allowing the standard molar heat capacity changes (Delta C-p degrees) also to be derived. Typical of the processes driven by the hydrophobic effect, Delta C-p degrees was observed to be proportional to the accessible (non-polar) surface area of the guest. The cyclic and acyclic guests displayed opposite trends; the heat capacity penalty upon binding increased with longer aliphatic chains, while the opposite was observed with the cyclic guests.