Preparation And Application Of Several Supramolecular Functional Materials Based On Macrocyclic Molecules

In the new era of rapid development,people put forward higher requirements for the performance of materials to meet the great needs of social production and people’s life.Miniaturization,intelligence and multifunction will be the research direction and development trend of new functional materials in the future.In recent years,supramolecular chemistry with molecular recognition and self-assembly as the main research content has aroused new research upsurge in the fields of chemistry,material science and life science.Among them,supramolecular functional materials based on macrocyclic molecules have attracted wide attention because of their unique characteristics of self-assembly,self-healing and stimulus responsiveness.And have shown great potential in catalysis,sensing and detection,adsorption and separation,biomedicine,electronic devices and other fields.In this paper,for developing the application range of supramolecular macrocycles further,several new supramolecular functional materials are designed and prepared from multiple angles to exert the molecular recognition and self-assembly of supramolecular macrocycles.And these functional materials also lay the foundation for the development of intelligent and multifunctional supramolecular materials.Based on the self-assembly properties of supramolecular macrocycles,the functional organic monomers are introduced into the assembly to prepare a stimulus-responsive framework material.On the other hand,the supramolecular macrocycles and multiple metal nanoparticles are combined to prepare hybrid functional materials,which can demonstrate the molecular recognition properties of supramolecular macrocycles.It consists mainly of the following four parts:（1）A 2D supramolecular organic framework（SOF）based on synthetic macrocycles has been constructed in water by a self-assembly strategy.Two new organic monomers of this SOF,possessing viologen and azobenzene functional groups,form a stimuli-responsive host–guest system upon cooperatively binding with cucurbit[8]uril rings.The reversible formation and dissociation of 2D SOF can be realized by the isomerization of azobenzene under ultraviolet and visible light.The light-responsive property of the SOF is highly reversible and stable for up to four cycles.Moreover,azoreductase produced by Escherichia coli can reduce the N=N double bond of azobenzene entities,resulting in fluorescence recovery of the system.As an excellent and effective fluorescent probe,the SOF can detect azoreductase activity for real-time monitoring of the growth process of Escherichia coli.（2）Carboxylatopillar[5]arene-modified Fe₃O₄magnetic nanoparticles（CP5-MNPs）,with excellent water solubility,preeminent magnetic response and highly controllable particle size distribution,are successfully prepared through a newly developed one-pot solvothermal strategy for the first time.Due to the strong supramolecular host-guest interactions in conjunction with appreciable magnetic responsiveness,CP5-MNPs show excellent adsorption performance and ultrafast adsorption efficiency in the separation and enrichment of organic cationic pollutants,including but not limited to methylene blue,crystal violet and dimethyl viologen.Significantly,the excellent dye separation performance of CP5-MNPs demonstrates a strong tolerance towards p H changes and a good resistance to inorganic salts interference.The materials’inherent features of easy recyclability and affordability endow them with great potentials in column adsorption filler for sewage regeneration and environmental purification.（3）A green synthesis strategy of carboxylate functionalized leaning pillar[6]arene-mediated gold nanoparticles（CLP6-Au NPs）without external energy sources and reducing agents has been developed for the first time.Due to the excellent water solubility and semi-rigid cavity structure of CLP6,CLP6-Au NPs,with controllable particle size,show excellent stability and dispersibility,and remain stable and homogeneous at room temperature over 3 months.Significantly,the reduction mechanism that phenyl ether bonds of CLP6 break to produce reductive phenols,which reduces the gold ions to Au NPs,is proved for the first time in this study.In addition,CLP6-Au NPs are applicable to the detection of diquat（DIQ）,a widely used toxic pesticide.（4）We modified the guest molecule sulfhydryl viologen on both ends of the gold nanorods by the method of ligand replacement,and prepared cucurbit[7]urea-modified gold nanospheres.Gold nanorods and gold nanospheres assemble spontaneously in aqueous solution under supramolecular host-guest interactions,forming a new assembly form.This structure has high application potential in nonlinear optics and other fields.