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Intermolecular Interactions and Chiral Recognition in Water

水中分子间相互作用和手性识别

基本信息

批准号：
10440211
负责人：
KANO Koji
金额：
$ 7.55万
依托单位：
Doshisha University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B).
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 2000
项目状态：
已结题

项目摘要

Complexation of p-methylbenzoate (p-CH_3-Ph-CO_2^-) and alkanoate anions (CnCO_2^-) with cyclodextrins (CDs) through hydrogen bonding in an aprotic polar solvent, DMSO-d_6, has been studied by means of ^1H NMR spectroscopy. Although undissociated p-methylbenzoic acid, p-CH_3-Ph-CO_2H, does not interact with CDs, p-CH_3-Ph-CO_2^- is bound to native CDs such as α-, β-, and γ-CDs with fairly large binding constants (K) through hydrogen-bonding interactions. Addition of small amounts of D_2O suppresses the formation of the hydrogen-bonded complexes, suggesting that hydrogen-bonding interactions between simple host having dense OH groups as hydrogen-bond donors and guest having the CO_2^- group as a hydrogen-bond acceptor hardly occur in aqueous solution.Thermodynamic parameters for complexation of polyvalent cyclodextrin cation and anion with oppositely charged guests have been determined in D_2O containing 0.02 M NaCl by means of ^1H NMR spectroscopy. Protonated heptakis (6-amino-6-deoxy) … More -β-CD (per-NH_3^+-β-CD) forms stable inclusion complexes with monovalent guest anions. The enthalpy (ΔH) and entropy changes (ΔS) for complexation of per-NH_3^+-β-CD with p-methylbenzoate anion (p-CH_3-Ph-CO_2^-) are 3.8±0.7 kJ mol^<-1> and 88.6±2.2 J mol^<-1>K^<-1>, respectively. The thermodynamic parameters clearly indicate that dehydration from both the host and guest ions accounts for the entropic gain in inclusion process of p-CH_3-Ph-CO_2^- into the per-NH_3^+-β-CD cavity. The acetate anion is not included into the per-NH_3^+-β-CD cavity, while the butanoate and hexanoate anions form the inclusion complexes. The complexation of the alkanoate anions is entropically dominated. Judging from these results, it may be concluded that Coulomb interactions cooperated with inclusion are required for realizing the large entropic gain due to extended dehydration.Tetrakis (p-sulfonatophenyl) porphyrin tetraanion (TPPS) forms an extremely stable 1 : 2 inclusion complex of permethylated β-CD (TMe-β-CD)(porphyrin : CD=1 : 2). The K value for this system in water is too large to be determined. Such a system is expected to act as a good model for hemoglobin and/or myoglobin. The we studied the system composed of Fe (III) TPPS and TMe-β-CD.The Fe (III) complex of TPPS also form a very stable 1 : 2 complex of TMe-β-CD in water at pH>5, while the stoichiometry of the CD inclusion complex is altered to 1 : 1 because of the effort of the net charge of the porphyrin ring. The CD-porphyrin complex shows a novel behavior of axial ligation of Cl^- and ClO_4^-. Less

用核磁共振波谱技术研究了在非质子极性溶剂DMSO-d_6中对苯甲酯（p-CH_3-Ph-CO_2^-）和烷烃酸阴离子（CnCO_2^-）与环糊精（CDs）的氢键络合作用。虽然未解离的对甲基苯甲酸p-CH_3-Ph-CO_2H不与CDs相互作用，但p-CH_3-Ph-CO_2^-通过氢键作用与α-、β-和γ-CDs等天然CDs结合，并具有相当大的结合常数(K)。少量D_2O的加入抑制了氢键配合物的形成，表明水溶液中以致密OH基团为氢键供体的简单寄主与以CO_2^-基团为氢键受体的客体之间的氢键相互作用几乎不发生。用^1H核磁共振谱法测定了在含0.02 M NaCl的D_2O中，多价环糊精正阴离子与带相反电荷客体络合的热力学参数。质子化七烷基（6-氨基-6-脱氧）More -β-CD （per-NH_3^+-β-CD）与单价客体阴离子形成稳定的包合物。对苯甲酸甲酯阴离子（p-CH_3-Ph-CO_2^-）与nh_3 ^+-β- cd络合的焓变（ΔH）和熵变（ΔS）分别为3.8±0.7 kJ mol^<-1>和88.6±2.2 kJ mol^<-1>K^<-1>。热力学参数清楚地表明，在p-CH_3-Ph-CO_2^-包合到per-NH_3^+-β- cd腔中的过程中，主离子和客体离子的脱水导致了熵增益。乙酸阴离子不包含在每- nh_3 ^+-β-CD腔中，而丁酸和己酸阴离子形成包合物。烷酸盐阴离子的络合是熵支配的。从这些结果可以得出结论，为了实现长时间脱水的大熵增益，需要库仑相互作用与包合物的协同作用。四（对磺酰基）卟啉四负离子（TPPS）形成非常稳定的过甲基化β-CD (TMe-β-CD) 1:1包合物（卟啉：CD= 1:2）。该体系在水中的K值太大，无法确定。这种系统有望作为血红蛋白和/或肌红蛋白的良好模型。研究了由Fe (III) TPPS和TMe-β-CD组成的体系。TPPS的Fe （III）配合物在pH为bbb50的水中也形成了非常稳定的1:2的TMe-β-CD配合物，而CD包合物的化学计量由于卟啉环的净电荷的作用而改变为1:1。cd -卟啉配合物表现出Cl^-和ClO_4^-轴向结扎的新行为。少