β-环糊精与有机胺之间包合作用的理论与实验研究

通过实验和理论计算方法研究了β-环糊精(CD)与乙二胺1及它的三个类似物: 二乙烯三胺2、三乙胺3和乙二胺四乙酸4之间的包合作用. 利用旋光法确定了β-CD与客体分子形成1:1型主–客体包合物, 在298.2 K下测定了包合物在水中的稳定常数(K). 采用半经验PM3方法考察了β-CD与短链脂肪胺1~7、环状脂肪胺8~11以及芳香胺12~13的分子间结合能力, 报道了β-CD与这些客体分子间的包合络合过程并讨论了这些包合体系之间的包合差异性. 变形能和水合能对包合体系的相互作用能的贡献均相当小. β-CD包合物的稳定性取决于主、客体分子之间的尺寸匹配. 对于β-CD与客体1~4形成的包合物而言, 旋光法测定的包合物的K值的顺序与PM3计算得到的包合物络合能绝对值的排序有很好的一致性.

Theoretical and Experimental Studies of the Inclusion Phenomena of β‐Cyclodextrin with Organic Amines

The inclusion complexations of β‐cyclodextrin (β‐CD) with ethylenediamine 1 and its three analogs, diethylenetriamine 2 , triethylamine 3 and ethylene diaminetetraacetic acid 4 were examined by means of both experimental measurements and theoretical calculations. From the polarimetric method, it was found that β‐CD could form 1/1 host‐guest inclusion complexes with these guests, and the formation constants (K) of the inclusion complexes have also been determined in aqueous solution at 298.2 K. Semiempirical PM3 calculations were carried out to assess the intermolecular binding ability of β‐CD to a series of short chain aliphatic amines such as guests 1 – 7 , cyclic aliphatic amines 8 – 11 , and aromatic amines 12 – 13 . The interaction processes between β‐CD and the guests were reported, and the complexation differences of β‐CD with these guests also discussed. The energy contribution from deformation energy or hydrate energy to interaction energy in the inclusion systems was found to be quite small. The stability of β‐CD inclusion complexes depended on the size fit between the host and guest. For β‐CD complexes of guests 1 – 4, the order of the K values from the polarimetric measurements is in good accordance with that of the absolute values of the complexation energies from PM3 calculations.