Structural properties of carboxylic acid dimers confined within the urea tunnel structure: an MD simulation study.
Structural properties of carboxylic acid dimers confined within the urea tunnel structure: an MD simulation study.
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尿素隧道结构内羧酸二聚体的结构特性：MD 模拟研究。
DOI：
10.1021/jp110137h
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发表时间：
2011
期刊：
影响因子：
--
通讯作者：
Ilott AJ
中科院分区：
文献类型：
--
作者：
Ilott AJ
采用大规模分子动力学方法模拟了脲与烷烃（十二烷）和链烷酸（十二烷酸）客体分子形成的固体包结物。客体和主体子结构的不相称性意味着这些系统的模拟是具有挑战性的，我们的研究结果对尿素包合物早期模拟中的一些简化假设提出了质疑。获得的详细信息的羧酸二聚体和烷基链的结构特性限制在纳米级隧道内的脲主体结构，包括手性的脲隧道的手性性质诱导的客体构象。客体分子沿着隧道轴的扩散系数（在300 K时）测定为0.091 ± 0.031（十二烷）和0.0063 ± 0.0013 <$2ps −1（十二烷酸），与烷烃/尿素系统的实验测量结果非常一致。弱有序观察客人在相邻的隧道，这是兼容的烷烃/尿素系统的实验测量之间，虽然模拟提供了更详细的分子水平的见解，这种超分子有序的性质。
Large-scale molecular dynamics simulations have been performed on solid inclusion compounds formed between urea and alkane (dodecane) and alkanoic acid (dodecanoic acid) guest molecules. The incommensurate nature of the guest and host substructures means that simulations of these systems are challenging, and our results call into question some of the simplifying assumptions made in earlier simulations on the urea inclusion compounds. Detailed information is obtained on the structural properties of the carboxylic acid dimers and alkyl chains confined within the nanoscale tunnels of the urea host structure, including the chirality of the guest conformation induced by the chiral nature of the urea tunnels. Diffusion coefficients (at 300 K) of the guest molecules along the tunnel axis were determined to be 0.091 ± 0.031 (dodecane) and 0.0063 ± 0.0013 Å2ps−1(dodecanoic acid), in good agreement with experimental measurements on alkane/urea systems. Weak ordering is observed between guests in neighboring tunnels, which is compatible with experimental measurements on the alkane/urea systems, although the simulations provide more detailed molecular-level insights into the nature of this supramolecular ordering.