Synthesis Of Quaternization Pillar[5]arene-based Supramolecular Sensors And Its Host-Guest Recognition Properties

Based on the literatures on the study of host and guest recognition and pillararene,this paper first introduces the research background of host and guest,and then elaborates the research background and research status of pillararene.It can be found that the identification of host and guest in pure water phase has important research value,and the identification in pure water phase is seriously restricted by water solubility of main body.In recent years,the emergence of water-soluble pillararene for the design of synthetic water-soluble sensor molecules?the host molecule?provides a new opportunity.By summing the literature,water-soluble pillararene can be grouped into two categories:cationically modified water-soluble pillararene and anionic modified water-soluble pillararene.Cationic modified water-soluble pillararene mainly include:quaternized pillararene derivatives,quaternary phosphonium pillararene derivatives,imidazolium salt modified aromatic derivatives,pyridine salt modified pillararene derivatives,and other salt modified pillararene derivatives.The anion-modified water-soluble pillararene is mainly carboxyl-based modification.On this basis,we designed and synthesized the quaternized water-soluble pillar[5]arene derivatives?P5?.The quaternized pillar[5]arene has an electron-rich molecular cavity,which is excellent in water solubility and carries a large amount of positively charged groups.Thus,quaternized pillar[5]arene has good water-soluble.We use the water-soluble host molecules to do two major categories of research,one directly with quaternized water-soluble pillar[5]arene derivatives?P5?and twenty kinds of amino acids in the pure water phase for specific identification.The results show that P5 can only be assembled with methionine in pure water phase,and yellow fluorescence is produced after assembly,while other amino acids can not be assembled with P5.Second,the water-soluble pillar[5]arene P5 and the specific function of non-water-soluble fluorescence sensor molecules assembled to form a new water-soluble supramolecular fluorescence sensor,and then the new water-soluble supramolecular fluorescence sensor for the metal cations and anions identify one by one.The results show that:first,in the pure water phase,P5 can self-assemble with the naphthalimide-like guest molecule B1 with fluorescence binding sites and do not dissolve in water to form water-soluble supramolecular sensor P5-B1.This newly formed supramolecular sensor,P5-B1,continuously recognizes Fe³⁺and F^-.Second,when adding the guest molecule 2-hydroxy-3-naphthoate?N1?to P5,P5 and N1 can also self-assemble in the pure water phase,and form a water-soluble supramolecular sensor P5N1.By introducing the competitive coordination mechanism,we successfully prepared the supramolecular sensors P5N1 and P5N1Fe based on the cationic water soluble pillar[5]arene.These sensors are capable of identifying Fe³⁺and F^-in a high selectivity in the aqueous phase,and can also be used as an ion detection tool based on supramolecular sensors and a rewritable safety display material.Therefore,the water-soluble quaternary pillar[5]arene and its self-assembled water-soluble supramolecule as a new water-soluble sensor is a kind of design and preparation method which can be used to detect guest molecules or ion in water efficiently and conveniently.