Design And Investigation Of Supramolecular Systems Constructed By Macrocyclic Hosts

Self-assembly is one of the most important research areas in supramolecular chemistry. Macrocyclic compounds such as cyclodextrin and cucurbituril play important roles in constructing novel functional and smart material due to their great properties.Design and study on supramolecular systems constructed by macrocyclic molecules is the thesis, which includes two parts:(1) construction and study on sensitive vesicle and organogel systems based on cyclodextrin;(2) synthesis of novel tri(viologen) derivatives and their binding with CB7, especially their electrochemical properties affected by CB7.1. Introduction. Firstly, the characteristic of supramolecular chemistry as well as different types of supramolecular interactions is introduced. Due to the distinct structures of cyclodextrins and cucurbituril, they play important roles in supramolecular self-assembly. Then the research background of sensitive vesicles and organogels based on cyclodextrins is reviewed in detail. Finally, the importance of study on encapsulation of cucurbituril and its research status are presented.2. Vesicles prepared from supramolecular cyclodextrin amphiphiles. Supramolecular cyclodextrin amphiphiles are composed of cyclodextrins and hydrophobic guest molecules. Vesicles prepared from this kind of amphiphiles are sensitive to external stimuli. Here, we investigate the self-assembly behavior of cyclodextrin with aromatic compounds. We found that both ethyl benzoate and diphenyl methane could form supramolecular amphiphiles with cyclodextrin, which could further assemble to form vesicles. This study provides a facile way to prepare this kind of sensitive vesicles and avoids the complicated synthesis, which makes the wide application of vesicles possible.3. Preparation and modulation of organogels based on cyclodextrin. In the presence of salts, P-CD and guest molecule could assemble to form organogel in DMF. We mainly focus on the effect of salts on organogels.The system is heat-set organogel in the presence of LiCl, that is, the gel could be formed with increasing temperature and turn into solution at room temperature. The heat-set gel turns into stable gel with the addition of proper amount of sodium acetate. While using sodium formate instead of LiCl, the system is the normal gel. The most intriguing character of this system is that the functional guest molecule can be introduced easily and endow the gel system with multi-responsiveness.4. Synthesis of tri(viologen) derivatives and their binding with CB7. The three viologen parts of the novel tri(viologen) compound can be encapsulated by CB7. Upon the encapsulation of viologen moiety inside cucurbit[7]uril, the protons of the guest that areclose to the oxygen portal of cucurbit[7]uril will have strong interactions with the oxygens and show interesting complexation-induced chemical shifts in1H NMR experiments. We also report data of two reference compounds to explain the interesting phenomena. CB7could form stable complexes with the tri(viologen) derivative guest indicated by MS spectra. The binding constant decreases in water which is proved by UV-vis.