Approach toward Artificial Enzyme Models Using Water-soluble Cyclophanes with Hyrophobic Cavities

针对含有二苯基甲烷单元的环番化合物在水溶液和膜表面的人工酶模型中的应用进行了研究，取得了以下结果。在含有二苯基甲烷单元的环番大环中引入咪唑基或硫醇作为催化官能团，合成了催化环番化合物，并比较了它们在水溶液(pH 8.65)中催化酯的能力。虽然观察到含咪唑基的环番化合物的加速倍数是3.8倍，但添加无反应的客体或不带环的4-甲基咪唑的对照实验表明，咪唑基环烷的加速不是由于与环番环腔中的客体反应所致。这些结果证明了催化环芳烃的设计的必要性，其中的催化基团位于与所含客体的反应中心非常接近的位置。合成了一种具有C2对称结构、具有两个羟基的旋光活性阴离子环番，作为一种能够引入催化官能团的新型手性疏水空腔。在水溶液(pD12.8)中，该环番与阳离子芳香族客体(K_3-10^3M^&lt；-1&gt；)有较强的络合作用。利用聚氯乙烯支撑的液膜体系，合成了一系列具有长烷基链的亲脂性环番化合物，以实现膜表面的分子识别，评价了客体诱导的膜电位变化。在苯环一侧带有一定带电基团、另一侧含有亲脂性烷基的环番化合物具有最大的势能变化，这是设计界面受体的一个重要原则。

Studies aiming at application of cyclophanes having diphenylmethane units to artificial enzyme models in aqueous solutions and at membrane surfaces were carried out, and the following results were obtained.1. Catalytic cyclophanes in which an imidazolyl or thiol group as a catalytic functional group was introduced to a cyclophane macrocycle having diphenylmethane units were synthesized, and their abilities to accelerate ester docomposition were compared in aqueous solution (pH 8.65). Although 3.8-fold acceleration was observed for a cyclophane having an imidazolyl group, control experiments with addition of a nonreactive guest or 4-methyl-imidazole without a cyclophane ring showed that the acceleration by the imidazolyl cyclophane was not due to the reaction with a guest included in the cyclophane cavity. These results manifested the necessity of the design of catalytic cylophanes in which the catalytic group is located in close proximity to the reactive site of the included guest.2. An optically active, anionic cyclophane having a C_2-symmetrical structure with two OH groups was synthesized as a new type of chiral hydrophobic cavity that is capable of introducing catalytic functional groups. This cyclophane showed strong complexation to cationic aromatic guests (K_3-10^3M^<-1>) in aqueous solution (pD12.8).3. A series of lipophilic cyclophanes having long alkyl chains were synthesized to achieve molecular recognition at a membrane surface, evaluated as guest-induced changes in membrane potential by using PVC-supported liquid membrane systems. A cyclophane having a definite charged group on one side and a lipophilic alkyl chain on the other side of the benzene rings gave greatest potential changes, indicating an important principle for designing interfacial receptors.