Synthesis of Pseudocyclophanes Bearing Multi-recognition Sites and the allosteric Control of Their Recognition Ability

本研究设计并合成了一种新的变构主体。变构主体1由两个2，2‘-联吡啶部分、两个双酚A骨架和一个铵部分组成。主体1与一个铜(I)离子结合，得到相应的四面体配合物--假环番，它有一个结合腔，并且氨基非常接近。在溶剂萃取法中，1-铜(I)络合物对黄素单核苷酸钠盐(FMN)的亲和力高于1。然而，在没有氨基的类似宿主中，没有发现铜(I)的有意义的作用。这些结果有力地表明，空穴与1-铜(I)的带电部分之间的协同作用对FMN的结合是重要的。用1-铜(I)萃取FMN后，加入偏亚铜或三乙胺盐酸盐将客体再次转移到水相。巴托普林与铜(I)强结合，定量破坏1-铜(I)。三乙胺盐酸盐与客体相互作用，以抑制1-铜(I)与客体的磷酸部分之间的相互作用。这些结果表明，假环番的骨架和氨基对客体的识别是重要的。实验结果表明，该系统实现了分子识别的开关控制。C-AMP的变构识别也获得了成功，我们相信这项研究为构建复杂有机分子在人工体系中的开关识别提供了新的基本途径。

In this study a new allosteric host was designed and synthesized. Allosteric host 1 consists of two 2,2'-bipyridine moieties, two bisphenol A skeletons, and an ammonium moiety. Host 1 binds a Cu(I) ion to give the corresponding tetrahedral complex, pseudocyclophane, which has a binding cavity and the ammonium group in close proximity. In solvent extraction, 1-Cu(I) complex showed a higher affinity toward flavin mononucleotide sodium salt (FMN) than 1. However, meaningful effect of Cu(I) is not found in a similar host, which does not have an ammonium moiety. These results strongly suggest that cooperative interactions between the cavity and the charged moiety of 1-Cu(I) are important for the FMN binding. After extraction of FMN with 1-Cu(I), the guest was moved to the aqueous phase again by the addition of bathocuproine or triethylamine hydrochloride. Bathocuproine strongly binds to Cu(I) to destroy 1-Cu(I) quantitatively. Triethylamine hydrochloride interacts with the guest to inhibit interaction between 1-Cu(I) and the phosphate moiety of the guest. These results indicated that the framework and the ammonium moiety of the pseudocyclophane are important for the recognition of the guest. In addition, the results show that on-and-off control of molecular recognition is achieved by using this system. A similar allosteric recognition of c-AMP was also performed successfully.We believe that this study provided a new and fundamental way to construct a sophisticated on-and-off system for recognition of complicated organic molecules in artificial systems.