Syntheses And Applications Of Pillar[n]arenes With Oligo(Glycol Chain)

The study of chemistry based on macrocyclic hosts is always an important aspect in the development of supramolecular chemistry. The discovery of new macrocyclic hosts with fascinating structures and properties can greatly promote the development of supramolecular chemistry. The macrocycles that were discovered in the early years have been studied deeply and applied in a variety of areas, including, supramolecular polymers, drug delivery systems, and chemosensors. In 2008, a new type of macrocycle, pillararenes have received a great attention and become a hot topic in supramolecular chemistry. In this dissertation, we mainly focus on the preparation of pillararenes with oligo (glycol chain), their host-guest properties and applications.In the first part, we studied the host-guest chemistry between pillar[5]arene with mono (glycol chain) and paraquat deravitives. Compared with the alkyl chain functionalized pillar[5]arenes, pillar[5]arene with mono (glycol chain) showed stronger binding ability. We also demonstrated that the host-guest complexation between pillar[5]arene and paraquat showed redox-responsive.The second part is about a novel redox-responsive macromolecular [2] pseudorotaxane constructed by pillar[5]arene-based host-guest interactions. we utilize this redox-controllable pillar[5]arene-based inclusion complex to construct the first pillararene-based amphiphilic macromolecular [2]pseudorotaxane, which can self-assemble to polymeric vesicles in water. Moreover, due to the redox responsiveness of this inclusion complex, polymeric vesicles were uesd for controlled release of water-soluble anticancer drugs.In the third part, we successfully synthesized a novel pillar[6]arene with mono (ethylene oxide) groups. We found that pillar[6]arene with mono (ethylene oxide) group could form a stable inclusion complex with diquat both in solution and in the solid state, whereas the pillar[5]arene analogue could not. It was found that the cavity of the pillar[6]arene is more suitable for the diquat guest than that of the pillar[5]arene.In the forth part, We report a novel molecular recognition motif between a new thermo-responsive water-soluble pillar[7]arene and an azobenzene derivative. This new recognition motif in water shows dual-responsiveness. Furthermore, we utilized this recognition motif to construct the first pillararene-based supra-amphiphilic polypseudorotaxane which can self-assemble to form vesicles in water. Due to the dual-responsiveness of the molecular recognition motif (the thermo-responsiveness of WP7 and photo-responsiveness of azobenzene), the reversible transformations between solid nanospheres and vesicles were achieved by adjusting the solution temperature or UV-visible light irradiation. These dual-responsive aggregation behaviours were further used in the controlled release of water-soluble dye calcein molecules.In the fifth part, we have successfully synthesized a water soluble pillar[10]arene with tri (ethylene oxide) groups (WP10), which showed excellent LCST behavior. It was found that the Tcloud of WP10 could be controlled upon addition of different amounts of diazapyrenium salt. Furthermore, owing to the chemical-responsive host guest complexation between WP10 and diazapyrenium salt, its clouding point could be reversibly controlled by adding DEA or TFA. This chemical controllable threading/dethreading led to chemical reversible switching of the LCST behavior.