Study On Supramolecular Self-assembly And Regulation Of Cucurbit[8]uril

Cucur[n]urils are a series of complexes with rigid structural and hydrophobic cavity.CB[n] family has many members like CB[5],CB[6],CB[7],CB[8],CB[10],CB[12] and CB[14].As an important subject molecule of supramolecular chemistry,which has been applied to molecular self-assembly,molecular recognition,drug delivery,chemical reaction and so on.Viologen derivates and CB[n] have abundant assembling patterns,especially Viologen derivatives and high electron density of the aromatic compounds could be co-encapsulated in C B[8] cavity to form ternary self-assembled complexes,through the charge transfer(C harge-transfer,C T)effect.The Viologen derivatives and CB[8] encapsulation are used in many research fields.It has been reported that C B[n] can be used in the regulation of photocatalytic addition reactions and 1,3-dipolar addition reactions.But CB[n] have not been used in the regulation of electrophilic substitution reactions.The electrophilic substitution reaction is a very important type of reaction that can be used to introduce a number of important functional groups on the aroma compound molecules,however,the separation of the products of this kind of reaction is very difficult.Based on the above issues,we synthesized a Viologen derivative molecule(PhEV).PhEV can be folded and encapsulated in CB[8] cavity through the intramolecular CT effect.Based on this self-assembly feature,CB[8] can be used as a molecular reactor to control the electron cloud density on the PhEV benzene ring,and then the electronic cloud density was determined by analyzing the brominated reaction product type on the PhEV benzene ring.In the presence of CB [8],the brominated reaction product is completely monobromo-PhEV.CB[8] can be used as an excellent molecular reactor to regulate the electrophilic substitution of these molecules.Then compared with the electrophilic substitution reaction of PhEV-CB [n](n = 6,7),and the mechanism of electrophilic substitution reaction was investigated.Resveratrol(Res)is a non-toxic side effects of anti-tumor activity of polyphenols.Most of the Res Most of the Res is metabolically excreted from the body in the administration process.We can through the drug carrier means to enable Res can quickly enter the cell,to overcome its rapid metabolism,dose-dependent defects.Based on the assembly characteristics of the C B[8] and the viologen derivatives,we designed and synthesized a sample of the pH fluorescent probe molecule(R3)connected by the rhodamine B precursor and the viologen through the flexible chain.Res with the probe R3 can be encapsulated in the CB[8] cavity through the C T effect,and C B[8] load Res into cells.The probe R3 can fluoresce inside the cancer cells,it is possible to monitor whether the ternary self-assembled complex enters cancer cel s by cell imaging techniques.