New Approaches to Cyclodextrin-Based Organic Nanotubes

在这个项目中，我们建议(A)开发新的有效的方法来制备可加工的环糊精纳米管(CyNT)，以及(B)使用先进的核磁共振方法来表征CyNT中小分子的传输。环碳纳米管将以模板导向的方法合成，包括(A)CD多轮烷的合成(B)通过其羟基使相邻的Cd交联化，(C)裂解塞基，(D)去除聚合物模板，以及(E)纯化。我们将同时合成二聚和多聚碳纳米管，并克服几个已知的困难：(1)碳纳米管的低分子量(2)多齿轮烷和碳纳米管的低产率和繁琐的分离(3)对α-CD的限制。聚轮烷的合成将采用一种新的方法，在这种方法中，聚合物生长、CDS的穿孔和停顿同时进行。将应用更好的交联反应，如复分解、相邻Cd的点击偶联。末端官能化的短碳纳米管的缩聚将导致高分子量的碳纳米管。我们将重点关注γ-CyNTs，因为它们还不为人所知，但非常适合于类固醇或紫杉醇等药物的包合和运输。轮烷化中间体和碳纳米管的组成、结构和大小将通过扩散有序核磁共振波谱(DOSY)进行表征。我们将使用固态和脉冲场梯度核磁共振技术来研究碳纳米管中探针分子的平移和旋转动力学，它们是样品载量和温度的函数。

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.