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

通过 ^1H 研究了对甲基苯甲酸 (p-CH_3-Ph-CO_2^-) 和链烷酸根阴离子 (CnCO_2^-) 与环糊精 (CD) 在非质子极性溶剂 DMSO-d_6 中通过氢键络合尽管未解离的对甲基苯甲酸，p-CH_3-Ph-CO_2H，不与 NMR 相互作用。 CDs、p-CH_3-Ph-CO_2^- 通过氢键相互作用与天然 CDs（例如 α-、β- 和 γ-CDs）结合，具有相当大的结合常数 (K)。氢键配合物的形成，表明具有密集OH基团作为氢键供体的简单主体与具有CO_2^-基团作为氢键受体的客体之间的氢键相互作用几乎不发生多价环糊精阳离子和阴离子与带相反电荷的客体络合的热力学参数已通过 ^1H NMR 光谱法在含有 0.02 M NaCl 的 D_2O 中测定。 CD (per-NH_3^+-β-CD) 与单价客体阴离子形成稳定的包合物。全NH_3^+-β-CD与对甲基苯甲酸阴离子(p-CH_3-Ph-CO_2^-)络合的熵变(ΔS)为3.8±0.7 kJ mol^<-1>和88.6±2.2 J mol ^<-1>K^<-1> 分别清楚地表明主体离子和客体离子的脱水导致了夹杂物的熵增益。 p-CH_3-Ph-CO_2^-进入per-NH_3^+-β-CD空腔的过程中，乙酸根阴离子不被纳入per-NH_3^+-β-CD空腔，而丁酸根和己酸根阴离子形成。从这些结果来看，链烷酸阴离子的络合是熵主导的，可以得出结论，库仑相互作用与包合是实现大熵所必需的。四（对磺基苯基）卟啉四阴离子（TPPS）形成极其稳定的全甲基化β-CD（TMe-β-CD）（卟啉：CD=1：2）的1：2包合物。该系统在水中的值太大而无法确定。我们研究了由以下组成的系统。 Fe (III) TPPS 和 TMe-β-CD。TPPS 的 Fe (III) 络合物在 pH>5 的水中也形成非常稳定的 1:2 TMe-β-CD 络合物，而 CD 包合物的化学计量由于卟啉环净电荷的作用，CD-卟啉复合物显示出 Cl^- 和 ClO_4^- 的轴向连接的新行为。较少的