环糊精及其甲基取代形式在水溶液中氢键的动力学。

Kinetics of hydrogen bonds in aqueous solutions of cyclodextrin and its methyl-substituted forms.

机构信息

Molecular Modeling Laboratory, Department of Chemistry, Indian Institute of Technology, Kharagpur 721302, India.

出版信息

J Chem Phys. 2011 Jan 14;134(2):025103. doi: 10.1063/1.3530781.

Abstract

Molecular dynamics simulations of β-cyclodextrin (BCD) and its two methyl-substituted derivatives, namely, heptakis(2,6-di-O-methyl)-β-cyclodextrin (DIMEB) and heptakis(2,3,6-tri-O-methyl)-β-cyclodextrin (TRIMEB) have been performed in aqueous solutions. Detailed analyses were carried out to investigate the effects of substitution on the kinetics of cyclodextrin-water and water-water hydrogen bonds formed by water present in the hydration layers around these macromolecules as well as those formed by water inside their cavities. It is observed that increased geometrical constraints due to substitution of the OH groups of the glucose rings of the BCD molecule result in rapid establishment of hydrogen bond breaking and reformation equilibria for DIMEB and TRIMEB. This has been found to be the microscopic origin of highly rigid arrangement of water around TRIMEB and inside its cavity, as against water in and around BCD and DIMEB.

摘要

已在水溶液中对β-环糊精（BCD）及其两种甲基取代衍生物，即：七（2,6-二-O-甲基）-β-环糊精（DIMEB）和七（2,3,6-三-O-甲基）-β-环糊精（TRIMEB）进行了分子动力学模拟。详细分析了取代对环糊精-水和水-水氢键的动力学的影响，这些氢键是由这些大分子周围水合层中存在的水以及它们空腔内的水形成的。观察到，由于葡萄糖环上的 OH 基团的取代导致 BCD 分子的几何约束增加，从而导致 DIMEB 和 TRIMEB 中氢键的断裂和形成平衡迅速建立。这就是在 TRIMEB 周围和其空腔内的水与 BCD 和 DIMEB 中的水相比呈现高度刚性排列的微观起源。