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受体。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Cu（I）离子结合，得到相应的四面体配合物，假环蕃，其具有结合腔和紧邻的铵基。在溶剂萃取过程中，1-Cu（I）配合物对黄素单甘肽钠盐（FMN）的亲和力高于1。然而，在不具有铵部分的类似主体中未发现Cu（I）的有意义的作用。这些结果强烈地表明，腔和1-Cu（I）的带电部分之间的合作相互作用对于FMN结合是重要的。在用1-Cu（I）萃取FMN之后，通过加入浴铜灵或三乙胺盐酸盐将客体再次移动到水相。浴铜灵与Cu（I）强烈结合，定量破坏1-Cu（I）。三乙胺盐酸盐与客体相互作用以抑制1-Cu（I）与客体的磷酸基团之间的相互作用。这些结果表明，假环蕃的骨架和铵基对客体分子的识别起着重要的作用。此外，实验结果表明，该系统实现了对分子识别的开关控制。本研究为人工体系中构建复杂的开-关识别系统提供了一条新的基本途径。

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.