| Traditional amphiphiles have limited development due to their relatively simple structures.Supramolecular chemists have developed new products by modifying amphiphile and introducing various non-covalent forces to regulate the system.Supramolecular amphiphiles have more convenient synthesis processes and more complex structures and properties than traditional amphiphiles,and the application direction is more diverse.In recent years,supramolecular macrocyclic hosts have been widely used in amphiphilic supramolecular assembly due to their diverse structural features and recognition capabilities.The multiple driving forces introduced by the macrocycle provide important support for the innovation of the structure and function of the amphiphilic supramolecular system,and bring a broader development prospect for the amphiphilic supramolecular assembly.In this dissertation,cucurbit[n]uril(CB[n])was selected as the structural motif of the macrocyclic amphiphilic system.Based on that,novel amphiphilic CB[n]motifs and new amphiphilic guest molecules are designed and synthesized as building blocks to construct supramolecular amphiphilic systems and functional materials.This dissertation consists of five chapters.Chapter 1 briefly describes the research status of supramolecular chemistry,and introduces the concept and structural characteristics of amphiphile,the production and research significance of supramolecular amphiphile,and the advantages and status quo of macrocyclic amphiphilic supramolecular systems.It also elaborates the research significance,system type and the development direction of the amphiphilic assembly system constructed by cucurbituril.After systematically researching and analyzing the above research results,the topic of this dissertation is proposed.Chapter 2 mainly designs and synthesizes two novel amphiphilic cucurbit[7]uril(CB[7])derivatives(1-2)for the construction of amphiphilic systems.The CB[7]derivatives(1-2)tend to form intramolecular self-inclusion compounds when they exist independent,respectively.Compound 1 acts as an amphiphilic structural unit after forming stable complexes 1·3 and 1·4 with different charged guests 3 and 4,respectively.1·3 and1·4 are used to build vesicle-type assembly through multiple non-covalent forces(host-guest interaction,electrostatic interaction,hydrophilic-hydrophobic interaction,etc.)in aqueous phase.The vesicle assembly has stimuli-responsiveness,while it achieves stable encapsulation and controlled release of rhodamine 6G(R6G),which can be used for drug delivery system,aqueous phase separation and catalysis,and biosensors,etc.Chapter 3 investigates the[2]rotaxane built by novel amphiphilic molecule and cucurbit[10]uril,and its supramolecular-induced fluorescence enhancement properties.Based on the results of Chapter 2,this chapter modifies the structure of the guest molecule in the amphiphilic system.The main design and synthesis of a novel amphiphilic guest molecule with a water-soluble viologen center and two hydrophobic tetraphenylethene(TPE)fluorophores is designed and synthesized,and forms supramolecular[2]rotaxane CB[10]·1 with cucurbit[10]uril(CB[10])by slipping method in the organic phase(DMSO).The formation of CB[10]·1 was accompanied by a significant enhancement of the fluorescent signal.Further studies have shown that the formation of CB[10]·1 and the stability of the stacked structure are jointly driven and regulated through multiple non-covalent forces(host-guest interaction,C=O···N~+ion-dipole interactions,C-H···?interactions,conjugated stacking,etc.).In this process,supramolecular forces induce changes in the electronic transfers and arrangement of CB[10]·1,and amplify the restriction of intramolecular rotation(RIR)of TPE units,which makes CB[10]·1 more susceptible to the excited state,thus exhibiting the remarkable enhanced properties of fluorescence,which can be used to construct a supramolecular luminescence system with various emission characteristics.Based on the research results in Chapters 2 and 3,Chapter 4 expands the structure and function of the amphiphilic CB[n]s.An amphiphilic cucurbit[6]uril(CB[6])derivative is modified by fragment synthesis,and this CB[6]derivative with hydrophobic CB[6]unit and hydrophilic alkoxy unit is synthesized and linked on activated silica gel,after that a novel amphiphilic CB[6]modified silica gel support was obtained.The silica gel carrier exhibits superior separation and purification ability compared with the conventional stationary phase when used in the stationary phase of the liquid chromatography preparative column,and exhibits better purification separation effect on the polyhydroxy compound which is difficult to purify and separate.The improvement of the separation and purification ability is achieved by the regulation of multiple supramolecular forces(host-guest recognition,hydrogen bond,C-H···?interactions,?-?stacking,etc.)brought about by the amphiphilic CB[6]unit in the silica gel carrier.It indicates that the amphirea urea amphiphilic supramolecular system also has application prospects in practical production.Chapter 5 explores the main synthesis method of new cucurbit[9]uril and other cucurbituril macrocycles.Based on all previous research results,this chapter focuses on the development of a new structure of the cucurbituril macrocyclic body.In this chapter,the best fragment synthesis method in the functionalization of cucurbituril is used,and glycouril oligomers with different configurations are used as raw materials to condense under various conditions by using template method and non-template method to synthesize cucurbit[9]uril,cucurbit[10]uril and new cucurbit[8]uril.Analysis of the reaction results shows that the appropriate template,lower reaction temperature and the appropriate concentration of acid solvent system are important conditions for the synthesis of the new cucurbituril macrocycles.The results obtained in this chapter provide not only valuable experience for the synthesis of the new cucurbituril,but also a new direction for the development of the cucurbituril amphiphilic assembly system,which is supposed to introduce new host-guest recognition behaviors and develop new supramolecular amphiphilic systems by constructing new cucurbituril macrocycles. |
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