New Approaches to Cyclodextrin-Based Organic Nanotubes

在这个项目中，我们建议(a)开发新的有效方法来加工环糊精纳米管（CyNT）， (b)使用先进的核磁共振方法来表征CyNT中小分子的运输。CyNTs将以模板导向的方法合成，包括(a)合成CD聚轮烷(b)通过其羟基交联相邻的CD， (c)切割阻挡基团，(d)去除聚合物模板，以及(e)纯化。我们将合成二聚体和聚合型CyNTs，并克服几个已知的困难：(1)CyNTs分子量低；(2)聚轮烷和CyNTs的收率低且分离繁琐；(3)α-CD的限制。聚轮烷的合成将采用一种新的方法，即聚合物的生长、CDs的穿线和封塞同时进行。将应用更好的交联反应，如复分解，相邻cd的点击耦合。端官能化短碳纳米管缩聚可得到高分子量碳纳米管。我们将重点关注γ- cynt，因为它们尚不为人所知，但非常适合用于类固醇或紫杉醇等药物的包裹和运输。旋烷化中间体和CyNTs的组成、结构和大小将通过扩散有序核磁共振波谱（DOSY）来表征。使用固态和脉冲场梯度核磁共振技术，将检测探针分子在cynt中的平移和旋转动力学作为样品负载和温度的函数。

In this project, we propose to (a) develop new efficient approaches to processable cyclodextrin nanotubes (CyNT) and (b) characterizing transport of small molecules in CyNTs using advanced NMR methods. CyNTs will be synthesized in a template directed approach, including (a) synthesis of CD polyrotaxanes (b) crosslinking adjacent CDs through their hydroxyl groups, (c) cleavage of stopper groups, (d) removal of polymer template, and (e) purification. We shall synthesize both dimeric and polymeric CyNTs and overcome several known difficulties: (1) low molecular weights of CyNTs (2) low yields and tedious isolation of polyrotaxanes and CyNTs (3) limitation on α-CD. Polyrotaxanes will be synthesized with a new methodology in which polymer growth, threading of CDs and stoppering are carried out simultaneously. Better crosslinking reactions will be applied, like metathesis, click couplings of adjacent CDs. Polycondensation of endfunctionalized short CyNTs will lead to high molecular weight CyNTs. We will focus on γ-CyNTs, because they are yet unknown but highly desirable for inclusion and transport of drugs like steroids or taxol. Composition, structure, and size of rotaxanated intermediates and CyNTs will be characterized by diffusionordered NMR spectroscopy (DOSY). Translational and rotational dynamics of probe molecules in the CyNTs will be examined as functions of sample loading and temperature using solid-state and pulsed-field-gradient NMR techniques.