| With the rapid development of supramolecular chemistry,intelligent responsive organic functional materials constructed based on host-guest recognition interaction have become a hot spot research area in material chemistry.As the typical class of organic functional materials,rotaxane molecular shuttles consists of a rod-like component and a ring-like component combined by host-guest recognition,and the two ends are blocked by large blocking groups.Under certain external stimuli,the ring component can make reversible shuttle motion along the rod-like component.Due to the good stimulus responsiveness of rotaxane molecular shuttles,it has important applications in the field of building intelligent responsive functional materials.As the first generation macrocyclic compound,crown ether has important applications in the field of constructing structurally complex and intelligent responsive rotaxane molecular shuttles due to its easy modification and good host-guest recognition properties.In recent years,the rotaxane molecular shuttles constructed based on crown ether system have received extensive attention in the field of preparing intelligent responsive functional materials,and the main contents and reaserch results of this thesis are as follows:In chapter 1,the basic concepts of host-guest recognition and rotaxane molecular shuttles are introduced,and the recent research progress of rotaxane molecules based on crown ether systems in the field of supramolecular polymers and self-assembly of material surfaces are reviewed.Firstly,the supramolecular polymers constructed based on different host-guest recognition structures such as: catenane,[c2]daisy chains,pseudorotaxane and rotaxane and their applications are introduced.Then the practical applications of smart responsive functional materials based on the self-assembly of rotaxane molecular shuttles on material surfaces in the fields of nanovalves,ion transport across membranes,and material surface modification are reviewed.In chapter 2,an acid-base responsive linear-cyclic structure reversibly transformed polymer [1] rotaxane molecular shuttle Poly-1-H with fluorescence signal output was designed and prepared.The target molecule Poly-1-H has an electron-rich ferrocene functional group and an electron-deficient naphthalimide group with strong fluorescence,which are linked by the [1] rotaxane structure and a poly(tetrahydrofuran)backbone.The structure of Poly-1-H was characterized by 1H NMR spectroscopy,mass spectrometry,size-exclusion chromatography,and infrared spectroscopy.The crown ether macrocycle of the target [1] rotaxane molecule Poly-1-H was able to shuttle between two different recognition sites along the polymer backbone under the stimulation of external acid-base(DBU/TFA)was investigated by 1H NMR spectroscopy.The change of linear-cyclic structure of the [1] rotaxane shuttle is accompanied by a change in fluorescence intensity due to the PET.In chapter 3,an amphiphilic [2] rotaxane molecular shuttle R-3 was designed,prepared and modified on a glass surface for the reversible modulation of the wetting properties.The target molecule R-3 is an amphiphilic [2] rotaxane molecular shuttle functionalised with a terminal alkyne group,introducing two groups with three hydrophilic tetraethylene glycol monomethyl ether chains on the crown ether macrocyclic component and blocked with three hydrophobic all alkyl chains at the terminus.The structure of the target molecule R-3 was characterized by 1H NMR spectroscopy and high resolution mass spectrometry.The target molecule R-3 was formed into a self-assembled monolayer SAM-R-3 on the glass surface by the click reaction and characterized by XPS spectroscopy and contact angle measurement.The system was able to modulate the hydrophilic properties of the glass surface by modulating the distance between the hydrophobic groups of the [2] rotaxane molecule shuttle by acid-base(DBU/TFA)stimulation,and subsequent data collection is still in progress. |
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