Elucidation of the Hydration Mechanism of Hydrophobic Groups in Organic Compounds as a Clue to Investigate Water Structures in Living Bodies

阐明有机化合物中疏水基团的水合机制作为研究生物体内水结构的线索

• 批准号: 13640504
• 负责人: MIZUNO Kazuko
• 金额: $ 2.24万
• 依托单位: Fukui University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2001
• 资助国家: 日本
• 起止时间: 2001 至 2002
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13640504/
• 关键词: external double reference method; temperature dependence of chemical shift; hydration of CH; Hydration mechanism; Blue-shifting hydrogen bond; bi-functional hydrogen bond; CH・・・O; 1,4-dioxane; ab initio M.O.法; ケミカルシフトの温度依存性; 外部複基準法; 疎水性基の水和メカニズ

1. Presentation of "The External Double Reference Method" to measure chemical shifts on a unified scaleAll the chemical shifts were measured by the external reference method using a capillary tube with a bulb at the bottom for a reference substance, and corrected in terms of the difference in bulk volume magnetic susceptibilities between the sample and a reference solution obtained in situ at every temperature. In the present work for the first time, we took the temperature dependence of the chemical shift and the bulk volume magnetic susceptibility of the reference solution into consideration to study temperature dependence of chemical sifts. We call the method the external double reference method.2. The denial of "The iceberg structure model" on the basis of some experimental proofs^1H-NMR and IR studies were carried out for 1,4-dioxane/H_2O, 1,3-dioxane/H_2O and 4-methyl-1,3-dioxane/H_2O mixtures over the whole concentration range at temperatures of 1, 25, and 50℃. ^1H NMR spectra w … More ere also acquired for mixtures. It was found that an anomalous polarization of the water molecules, which had been observed in the dimethylsulfoxide/H_2O and acetone/H_2O mixtures, did not occur in the three different aqueous dioxane mixtures, in which ΔH and ΔS for mixing are negative in water-rich region and so-called hydrophobic hydration occurs. Thus, we have concluded that the hydrophobic moiety in an organic solute itself does not play a role to cause anomalously high polarization of the water molecules. We have also concluded that the hydrogen-bonding basicity of the polar group is an important factor for the anomalous polarization of the water in the water-rich region.3. A new mechanism for the hydration of CH groups in organic compounds with polar groupsIt was found that the frequencies of IR C-H stretching vibration modes of 1,4-dioxane increase and the absorption intensities of the modes decrease with increasing water concentration. Since these spectroscopic features correspond well to the formation of the blue-shifting C-H・・・OH_2 hydrogen bonds obtained from ab initio calculations for complexations in gas phases, we can categorize the solvation of the C-H groups in the dioxanes in aqueous solutions as blue-shifting C-H・・・O hydrogen bonding. Thus we propose for the first time that the hydration of CH groups in organic solutes having a polar group is due to the formation of blueshifting C-H・・・OH_2 hydrogen bonds. We propose the formation of a bi-functionally hydrogen-bonded hydration complex in which each water molecule plays a role as both a proton donor in the conventional O-H・・・X(O, N, ..) hydrogen bonding and an proton acceptor in the blue-shifting C-H・・・O hydrogen bonding simultaneously, X・・・H-O(H)・・・H-C. Less

1.介绍一种在统一标度上测量化学位移的“外部双重参考法”所有化学位移均采用外部参考法测量，使用底部带有灯泡的毛细管作为参考物质，并根据在每个温度下原位获得的样品和参考溶液之间的总体积磁化率差异进行校正。在本工作中，我们第一次考虑到温度的化学位移和体积磁化率的参考溶液的依赖关系，研究化学位移的温度依赖性。我们称该方法为外部双重引用方法。2.本文对1，4-二氧六环/水、1，3-二氧六环/水和4-甲基-1，3-二氧六环/水在1，25和50℃的全浓度范围内进行了~ 1H-NMR和IR研究。^1H NMR谱， ...更多信息 这里也获得了混合物。结果表明，在二甲基亚砜/H_2O和丙酮/H_2O混合体系中，水分子的反常极化现象在三种不同的二氧六环水溶液中没有发生，在富水区混合的ΔH和ΔS均为负值，发生了所谓的疏水水合作用。因此，我们得出结论，在有机溶质本身的疏水部分不发挥作用，导致水分子的高极化。极性基团的氢键碱性是导致富水区水异常极化的重要因素.本文研究了含极性基团有机化合物中CH基团水合作用的新机理，发现随着水浓度的增加，1，4-二氧六环的红外C-H伸缩振动模式频率增加，吸收强度降低。由于这些光谱特征很好地对应于由气相络合从头计算得到的蓝移C-H···OH_2氢键的形成，我们可以将二氧六环中C-H基团在水溶液中的溶剂化归类为蓝移C-H···O氢键。因此，我们首次提出，在含有极性基团的有机溶质中，CH基团的水合作用是由于形成了蓝移的C-H···OH_2氢键。我们提出了一种双功能氢键水合复合物的形成，其中每个水分子在传统的O-H···X（O，N，.）氢键和质子受体同时存在于蓝移C-H···O氢键中，X···H-O（H）···H-C.少

项目成果

Kazuko Mizuno, Shingo Imafuji, Teruko Fujiwara, Tomoko Ohta, and Yuka Tamiya: "Hydration of the CH Groups in 1,4-Dioxane Probed by NMR and IR : Contribution of Blue-shifting CH・・・OH_2 Hydrogen Bonds"J. Phys. Chem. B. 107(16). 3972-3978 (2003)

Kazuko Mizuno、Shingo Imafuji、Teruko Fujiwara、Tomoko Ohta 和 Yuka Tamiya：“通过 NMR 和 IR 探测 1,4-二恶烷中 CH 基团的水合：蓝移 CH···OH_2 氢键的贡献”J。化学B.107(16)。

Mizuno, K., Imafuji, S., Fujiwara, T., Ohta, T., Tamiya, Y.: "Hydration of the CH Groups in 1,4-Dioxane Probed by NMR and IR : Contribution of Blue-shifting CH…OH_2 Hydrogen Bonds"J.Phys.Chem.B. 107・18. (2003)

Mizuno, K.、Imafuji, S.、Fujiwara, T.、Ohta, T.、Tamiya, Y.：“通过 NMR 和 IR 探测 1,4-二恶烷中 CH 基团的水合：蓝移 CH 的贡献…… OH_2 氢键”J.Phys.Chem.B. 107・18. (2003)

Mizuno, K., Imafuji, S., Fujiwara, T., Ohta, T., Tamiya, Y.: "Hydration of the CH Groups in 1,4-Dioxane Probed by NMR and IR : Contribution of Blue-shifting CH…OH_2 Hydrogen Bonds"J. Phys. Chem. B. 107. 3972-3978 (2003)

Mizuno, K.、Imafuji, S.、Fujiwara, T.、Ohta, T.、Tamiya, Y.：“通过 NMR 和 IR 探测 1,4-二恶烷中 CH 基团的水合：蓝移 CH 的贡献…… OH_2 氢键”J. Phys. Chem. B. 107. 3972-3978 (2003)