Nature of Supramolecular Complexes Controlled by the Structure of the Guest Molecules: Formation of Octa Acid Based Capsuleplex and Cavitandplex
Nature of Supramolecular Complexes Controlled by the Structure of the Guest Molecules: Formation of Octa Acid Based Capsuleplex and Cavitandplex
复制标题
DOI：
10.1021/la901367k
复制
发表时间：
2009-09-15
期刊：
影响因子：
3.9
通讯作者：
Ramamurthy, V.
中科院分区：
文献类型：
--
作者：
Jayaraj, Nithyanandhan;Zhao, Yaopeng;Ramamurthy, V.
八乙酸（OA）是一种人工合成的深腔腔体，通过研究一些不同尺寸和功能的有机分子与OA的络合行为，研究了影响有机分子包合的因素。已经注意到两种类型的配合物的形成：一种我们称为空腔复合是部分开放的配合物，其中一部分客体分子仍然暴露在水中，另一种称为胶囊复合是通过两个OA分子的组装形成的。在胶囊旅馆里，客人不会接触到水。通常，具有离子头基团的客体分子形成空腔和复形，而所有其他分子形成胶囊复形。胶囊复合剂可在胶囊内含有一个或两个客体分子。长度小于10埃的有机小分子可以形成2:1和2:2的胶囊结构，而长度较长的有机分子（小于12埃）则优先形成2:1的胶囊结构。广泛的H-1核磁共振实验已经进行表征主客体配合物。在没有客人的情况下，OA倾向于在水中聚集。聚集的程度取决于OA的浓度和溶液中盐的存在。我们期望从这项研究中获得的信息在预测给定客人的综合体性质和促进研究人员选择适当的客人方面具有很大的价值。
Factors that govern inclusion of organic molecules within octa acid (OA), a synthetic deep cavity cavitand, have been delineated by examining the complexation behavior of a number of organic molecules with varying dimensions and functionalities with OA. The formation of two types of complexes has been noted: the one which we call cavitandplex is a partially open complex in which a part of the guest Molecule remains exposed to water, and the other termed capsuleplex is formed through assembly of two OA molecules. In capsuleplex, the guest is protected from water. Generally, guest molecules that possess ionic head groups form cavitandplex, and all others form capsuleplex. Capsuleplex may contain one or two guest molecules within the capsule. Small organic molecules (< 10 angstrom in length) may form both 2:1 and 2:2 capsuleplex, while longer ones (> 12 angstrom) preferentially form 2:1 capsuleplex. Extensive H-1 NMR experiments have been carried out to characterize host-guest complexes. In the absence of the guest, OA tends to aggregate in water. The extent of aggregation depends on the concentration of OA and the presence of salts in solution. We expect the information obtained from this study to be of great value in predicting the nature of complexes with a given guest and facilitating appropriate guest chosen by researchers.