Volumetric Properties for the Binding of 1,4-Dioxane to Amide Naphthotubes in Water
Volumetric Properties for the Binding of 1,4-Dioxane to Amide Naphthotubes in Water
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水中 1,4-二恶烷与酰胺萘管结合的体积特性
DOI：
10.1021/acs.jpcb.0c07690
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发表时间：
2020
期刊：
影响因子：
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通讯作者：
Ryo Kitahara
中科院分区：
文献类型：
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作者：
Shujie Li;Huan Yao;ShTomoshi Kameda;Wei Jiang;Ryo Kitahara
萘基分子管和小分子之间的主客体相互作用已经被研究以理解选择性识别。然而，络合的体积性质在很大程度上仍然未知。在这项研究中，我们研究了1，4-二氧六环与一对萘甲酸酯（即，反式和顺式异构体），每个在疏水腔中具有两个向内指向的酰胺基团，使用核磁共振和荧光光谱结合压力扰动。我们发现，1，4-二氧六环与萘并管缔合的偏摩尔体积变化对于反式异构体为−6.3 ± 0.1 mL/mol，对于顺式异构体为3.2 ± 0.4 mL/mol。此外，萘并环酮与1，4-二氧六环形成的氢键比与水分子形成的氢键可压缩性差，表明萘并环酮与1，4-二氧六环形成的配合物中存在更刚性的氢键.分子动力学模拟表明，在顺式异构体的空腔的一个开口扩大，因为四个COO-电荷之间的排斥，这使得更多的水分子进入疏水空腔比在反式异构体的情况下。偏摩尔体积变化的差异被解释为在萘酚管疏水腔的水合的变化。对1，4-二氧杂环己烷-萘甲酸酯络合过程中体积变化的分子基础的深入理解可能会为配体与生物受体的结合提供见解。
Host–guest interactions between naphthalene-based molecular tubes and small molecules have been studied to understand selective recognition. However, the volumetric properties of complexation remain largely unknown. In this study, we investigated the volumetric properties for the binding of 1,4-dioxane to a pair of naphthotubes (i.e., anti- and syn-isomers), each possessing two inwardly directed amide groups in the hydrophobic cavity, using nuclear magnetic resonance and fluorescence spectroscopy coupled with pressure perturbation. We found that the partial molar volume change for the association of 1,4-dioxane with the naphthotube was −6.3 ± 0.1 mL/mol for the anti-isomer and 3.2 ± 0.4 mL/mol for the syn-isomer. Moreover, the hydrogen bonds of the naphthotubes with 1,4-dioxane were less compressible than those with water molecules, indicating that more rigid hydrogen bonds existed in the complexes with 1,4-dioxane. Molecular dynamics simulations showed that one opening of the cavity in the syn-isomer was widened because of the repulsion between the four COO–charges, which allowed more water molecules to access the hydrophobic cavity than in the case of the anti-isomer. The difference in the partial molar volume change was explained by variations in the hydration of naphthotube hydrophobic cavities. The enhanced understanding of the molecular basis of volume changes during 1,4-dioxane–naphthotube complexation may provide insights into ligand binding to bioreceptors.