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Control of Molecular Assembly for Modified Cyclodextrins by Electric Stimulus

电刺激控制改性环糊精的分子组装

基本信息

批准号：
07651114
负责人：
EGASHIRA Naoyoshi
金额：
$ 1.09万
依托单位：
Oita University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

项目摘要

We prepared novel beta-cyclodextrins (1 and 2) modified with viologen and nicotinamide moieties which were bind through a long alkyl chain (n=10), respectively. The cyclodextrins were purified by liquid chromatography and identified by NMR.^1H NMR and NOE (D_2O) strongly suggested that the methylene moiety of 1 was included in the CD cavity. Two-step reversible waves were observed in the cyclic voltammogram. Interestingly, the current of the first reduction wave was almost 30% of that of the second one which was 70% of the current expected from a reversible one electron transfer. The small currents of 1 may be due to formation of a super molecular, a kind of oligomer, through intermolecular inclusion which leads to an decrease in the diffusion coefficient. The large difference between the first and second currents can be also explained by formation of more highly stable inclusion complex for 2^+. An increase in viscosity of an aqueous solution of 1 strongly suggested formation of the oligomer. The controlled-potential electrolysis at the second wave led to an decrease in viscosity, the viscosity change is reversible.For 2, the formation of a stable inclusion complex was also confirmed by NMR.A weak inductive circular dichlonism spectrum due to the nicotinamide moiety suggested the existence in the neighborhood of nhe limb of the cyclodextrin cavity The experiment for the electric stimulus was not performed because the cathodic wave was irreversible.In conclusion, both cyclodextrin derivatives formed highly stable inclusion complexes and the change in an intermolecular inclusion complex of 1 by electric stimulus was observed as we had expected. We are studying a cyclodextrin derivative designed so as to show a large change in viscosity by electric stimulus.

我们制备了一种新的-环糊精（1和2），它们分别由一个长烷基链（n=10）修饰。采用液相色谱法对环糊精进行了纯化和核磁共振鉴定。^1H NMR和NOE （D_2O）强烈表明1的亚甲基部分包含在CD腔中。在循环伏安图上观察到两步可逆波。有趣的是，第一个还原波的电流几乎是第二个还原波的30%，这是一个可逆电子转移预期电流的70%。1的小电流可能是由于分子间包合形成了一种超分子，一种低聚物，导致扩散系数降低。第一和第二电流之间的巨大差异也可以解释为2^+形成了更稳定的包合物。水溶液粘度的增加强烈地暗示了低聚物的形成。在第二波控制电位电解导致粘度下降，粘度变化是可逆的。对于2，形成稳定的包合物也被核磁共振证实。由烟酰胺部分引起的弱感应圆二时性谱表明在环糊精腔的边缘附近存在。由于阴极波是不可逆的，因此没有进行电刺激实验。综上所述，两种环糊精衍生物均形成了高度稳定的包合物，电刺激下分子间包合物1的变化与我们预期的一致。我们正在研究一种环糊精衍生物，其设计目的是在电刺激下表现出较大的粘度变化。