Study On The Supramolecular Assembly Of Calixpyridine Salt And Anionic Gemini Surfactant, Fluorescent Whitening Agent And Sodium Fluorescein In Aqueous Solution And Its Functional Application

Macrocyclic chemistry is one of the most important parts in the study of supramolecular chemistry.In the past few decades,the study of supramolecular recognition and assembly based on crown ether,cyclodextrin,calixarene and cucurbituril is in the ascendant.In recent years,the research on the new macrocycles represented by pillararene and biphenarene has been widely concerned.However,none of these macrocyclic hosts are receptors specifically and selectively for anionic guest in aqueous solution.Calixpyridinium is a new type of cationic macrocyclic host,which shows good bonding properties to anionic guest in aqueous solution.However,up to now,the research on the molecular assembly of functional anion guest in aqueous solution based on calixpyridinium is not systematic.Based on this,we have carried out the following work:1.Surfactants can self assemble into molecular assemblies through hydrophobic effect.However,as far as we know,there are few reports about how to reduce the critical aggragation concentration of anionic surfactants by the binding of macrocyclic host with anionic surfactants.In this work,we have developed a method to effectively reduce the critical aggragation concentration of anionic gemini surfactants by the binding of calixpyridinium.The size of the nanostructures assembled by the amphiphilic complexes of calixpyridinium and the anionic surfactant sul-8 can be precisely controlled by adjusting the molar ratio of the host and guest mixtures.These results are very important not only in the construction of chemical responsive micelle system,but also in the field of biomimetics and molecular recognition.2.Stimulus responsive host–guest system has attracted much attention because of its wide application value in memory storage,intelligent materials,drug delivery,sensing and many other fields.Compared with other stimulus signals,light signal is more popular because it is a non-invasive and low-cost stimulus signal.It is still a challenging task to explore new molecular recognition units to construct photoresponsive host–guest system,especially in aqueous solution,which will promote the further development of green photoresponsive supramolecular materials.Up to now,the photoresponsive host–guest recognition unit based on calixpyridinium in aqueous solution has not been reported.In this work,we systematically studied the host–guest interactions of calixpyridinium and fluorescent whitening agent CBS in aqueous solution.We found that the amphiphilic assembly of calixpyridinium and CBS is photolysis due to the enhancement of photostimulation on the addition reaction of water and CBS.Such an effective photolysis system promoted by supramolecular aggregation has rarely been reported.This new photoresponsive host–guest recognition unit based on calixpyridinium is expected to be able to construct a variety of photoresponsive assemblies and show important application value in the design of photodegradable materials.The amphiphilic assembly of calixpyridinium and CBS was further found to be able to be used as a fluorescent enhanced selective recognition sensor for lysine.3.Molecular self-assembly is an important strategy in the field of nano supramolecular assembly.The morphology of the assembly can be precisely controlled by the reasonable design of its construction unit.Therefore,it is a very attractive topic to construct controllable nanoscale assemblies by designing reasonable molecular building blocks.As far as we know,there are few studies on the self-assembly of functional anion guest and different macrocyclic hosts.In this work,we studied the self-assembled behavior of fluorescein sodium with calixpyridinium and ?-cyclodextrin,and found that the supramolecular assembly formed by fluorescein sodium with calixpyridinium could be further co-assembled with bioactive anionic guest.4.The controllable control of the assembly is the precondition to realize the function of the assembly.Therefore,the construction of stimulus responsive assembly is a very interesting and important topic.However,as far as we know,most of the reported stimulus responsive assemblies are for single signal response.It is an interesting and meaningful research topic to construct multi-stimulus responsive assembly with response to multiple signals.Up to now,there are few studies on stimulus responsive assembly based on calixpyridinium and functional anionic guest,especially on photoresponsive and multi-stimulus responsive assembly.In this work,we have constructed a supramolecular assembly with calixpyridinium as the host and fluorescent whitening agent VBL as the guest,which has good response to light,heat and pH.We also found that this assembly exhibited different response to light signal under different pH conditions.