Fluorescent Probe And Supramolecular Vesicles Constructed By Pillararene-Based Pseudorotaxanes

Pillararene is the 5th new macrocyclic host after crown ethers,cyclodextrins,calixarenes and cucurbiturils.Since reported in 2008,pillararenes have attracted great attention owing to its highly rigid and symmetrical pillar architecture.So far,various types of pseudorotaxanes are constructed by functionalized pillararenes,which are sensitive to environmental stimuli,and they will play an important role in nano-materials,chemical sensors,transmembrane channel and supramolecular polymers.In this dissertation,we investigated the property of the supramolecular polypseudorotaxane networks constructed by pillar[5]arene-functioned tetraphenylethylene(TPEP5)as a fluorescent sensor.Furthermore,we designed a target drug delivery system based on functionalized water-soluble pillar[5]arene.This main content consists of the following two parts:In the first part,we synthesized a pillar[5]areae-functionalized tetraphenylethylene(TPEP5)derivative and a neutral guest molecule containing triazole groups(Gl)through Cu-catalyzed;"click" reaction,and supramolecular polypseudorotaxane networks could be obtained driven by the host-guest interactions between pillar[5]arene and Gl.The fluorescence emission of TPEP5 in solution is weak due to the active intramolecular rotations of the multiple phenyl rings in tetraphenylethylene that consumes its excitation energy through nonradiative channels.However,after adding G1 to the solution of TPEP5,the formation of the polypseudorotaxane networks via the threading of G1 into the cavity of the pillar[5]arene units restricted the rotation of phenyl rings in tetraphenylethylene,which blocks the nonradiative energy dissipation pathways,then the emission of TPEP5 is gradually enhanced as a result.These results indicate that TPEP5 is a typical aggregation-induced emission molecule.Moreover,the collapse of the polypseudorotaxane networks occurred upon addition of the completive guest adiponitrile,which facilitates the internal rotation within tetraphenylethy’lene moieties,and thus the fluorescence becomes weak again.In the second part,we designed a target drug delivery system based on functionalized water-soluble pillar[5]arene,which is modified by introducing an anticancer drug doxorubicin via an alkyl chain.This functionalized pillar[5]arenes are expected to form vesicles in water.At the same time,we are synthesizing a sulfonate guest molecule bearing target group RGD peptide,assume it can be decorated on the surface of vesicles through the host-guest interaction between sulfonate guest and water-soluble pillar[5]arene.Follow-up research work is currently underway.