Construction Of Topologically Novel Rotacatenanes Using Rotaxane And Catenane Frameworks

The mechanical bonds widely existing in numerous molecules such as rotaxanes, catenanes, knots and links, have evoked considerable interest in exploring intriguing architectures and topologies, molecular switches and devices, nanotechnology, biological functional machines, drug delivery and materials science based on mechanically interlocked structures. As a result, the design and construction of mechanically interlocked molecules (MIMs) that had novel configuration became one of the most popular research projects in supramolecular chemistry and self-assembly. Accompany with the great development of MIMs, rotaxanes and catenanes, as the most common MIMs, have showed the trends from single and simple structures to complicated and polymeric structures over the past decades. On the whole, the construction of novel mechanically interlocked structures has become a fashion due to the requirements of topology and their potential application in molecular machines and devices. Rotaxane and catenane as two basic topological frameworks can be used to construct the fused structures.This thesis included two parts:(1) Construction of rotacatenanes based on aza crown ethers, (2) Construction of [2]pseudorota[2]catenane based on CB[6] and aza crown ethers. The research results were summarized as follow:1. A class of novel ammonium backbones was synthesized, in which the ammonium on the linear component of backbone acted the function with construction of rotaxane while another ammonium on the macrocyclic component of backbone played the role of construction of catenane. Accordingly, they were subjected to perform the dynamic covalent chemistry, resulting a series of [n]rota[n]catenane structures (n= 2,3,4). In this process, the N-hetero crown ether components were installed on ammonium template sites of linear and macrocyclic components all at once by the template-directed clipping reaction. The results showed that the novel building blocks could assemble with high efficiencies.2. Similarly, another novel ammonium backbone was also synthesized. Accordingly, it was subjected to result a [2]pseudorotaxane structures including CB[6] by a "threading" approach. And then we has also found the CB[6] complex could be reacted in a clipping research by 1H NMR experiment.Finally, these investigations provide a foundation for future studies aimed at constructing the complicated integration or polymer with multi topological units.