Construction And Application Of Pillar[5]Aromatic Rotaxane

Pillararenes are a new generation of macrocyclic molecules composed of hydroquinone units connected by methylene bridges.Pillararenes are similar in structure to calixarenes,but their structures are more symmetrical and thermodynamically more stable.Pillararenes show excellent host-guest binding properties.They can not only recognize ionic guest,but also selectively interact with neutral guest.Its unique symmetrical structure and easy functionalization make it show excellent performance in the construction of interesting host guest chemistry,and provide a useful platform for the manufacture of supramolecular systems with various stimulus responses.In this paper,a series of rotaxanes and pseudorotaxanes based on pillar[5]arenes were designed and synthesized,and their self-assembly,aggregationinduced fluorescence and other properties were studied,and they were applied to construct various stimuli-responsive supramolecular drug delivery systems and high-performance composites.The main research contents are as follows:1.A series of compounds were prepared by bridging aminoalkyl-functionalized pillar[5]arenes with linear molecular mesochains containing thiourea groups.Different bis[1]rotaxanes can be prepared by changing the length of diaminoalkylene chain.Through a series of characterization,it is proved that bis-[1]rotaxanes can be formed by two longer diaminoalkylene units penetrating into two cavities of two pillar[5]arenes.2.Based on the characteristics of easy modification and functionalization of pillar[5]arenes,a series of compounds were prepared by coupling the tripyridine group,which is easy to form transition metal complexes with metals,with monofunctional pillar[5]arenes.The amphiphilic polyethylene glycol（PEG）group is selected as the guest molecule and the pillar[5]arene derivative with pillar[5]arene as the main body forms a complex through host guest interaction.TEM and DLS show that it can self assemble into spherical nanoparticles with uniform particle size in solution.The formed nanoparticles have good pH responsiveness and high drug loading rate for doxorubicin（DOX）.Nano ions show good imaging ability and certain anticancer activity on living cells.3.A series of macrocyclic compounds were prepared by coupling monofunctional pillar[5]arenes with tetrastyrene derivatives groups with aggregation-induced fluorescence effect（AIE）effect.pillar[5]arenes did not affect the AIE effect of tetrastyrene group,and the synthesized macrocyclic compounds also had AIE effect,showing a selective response to 2,4,6-trinitrophenol（TNP）.The as-synthesized compounds show great potential for TNP detection in aqueous and organic solvents at λEX=300 nm.The pillar[5]arene changes and enhances the fluorescence value of the tetrastyryl group at λEX=350 nm,which improves the specificity and sensitivity of TNP detection.