The Host-guest Bingding Interaction Between Cucurbit[7] Uril And Axial Organic Molecules

At the heart of supramolecular chemistry is the fine control and understanding of noncovalent interactions.A subclass is the formation of host-guest complex through molecular recognition between molecular receptor(host)and ligand(guest).Cucurbit[n]uril(Q[n]s),as an important host molecule,has attracted extensive attention.It can not only encapsulate various guest molecules,but also coordinate with a variety of metal ions,thus establishing host-guest chemistry based on Q[n].In the first chapter,the synthesis and development of cucurbit[n]uril,the structure and properties of cucurbit[n]uril,and the application of cucurbit[n]uril in host and guest chemistry were reviewed.Finally,the work of this paper is briefly introduced.In the second chapter,4,4’-bipyridine and p-chloromethyl benzoic acid were used as raw materials to design and synthesis of chain molecular guest 1(unilateral guest)and guest 1’(bilateral guest).They interact with Q[7] in aqueous solution respectively to form acid inclusion complex and basic inclusion complex.The inclusion mode of guest 1 and Q[7] was studied by NMR technology.Through solid ultraviolet diffuse reflection spectroscopy,fluorescence spectrometry,electron spin resonance technique,infrared spectroscopy,X-ray powder diffraction method,electrochemical cyclic voltammetry study acid inclusion compound of under 300 W xenon lamp irradiation photochromic phenomenon and alkaline clathrate under 140 ℃ heating conditions cause discoloration phenomenon,The discoloration mechanism was also analyzed.In chapter 3,guest 1 was used to react with o-phenylenediamine to generate chain molecules(Guest 2)containing benzimidazole groups and purpurine groups.The guest 2 was used to interact with Q[7] and TMe Q[6] in aqueous solution to form host-guest inclusion complexes,and its inclusion mode was studied by using nuclear magnetic resonance technology.It was found that the inclusion complex had photochromism.The photochromism of the inclusion complex under 300 W xenon lamp was studied by solid ultraviolet diffuse reflectance spectroscopy and infrared spectroscopy.Finally,the fluorescence properties of the inclusion complex were tested.Chapter 4 synthesis of axial molecules by the action of acetic acid,butyric acid,caproic acid,octanal and o-phenylenediamine respectively: Guest 3,guest 4,guest 5,guest 6,and then the guest in aqueous solution with Q[7] and TMe Q[6],using nuclear magnetic resonance technology,UV-visible absorption spectroscopy to study the guest and cucurbit[n]uril binding mode,designed different carbon chain length p H controlled molecular switch.The innovation of this paper lies in the design of two kinds of purple essence axis molecule,a purple essence benzimidazole axis molecule.The three molecules interact with Q[7] or TMe Q[6] to form quasi rotaxanes with different inclusion modes,and all of them have excellent photochromic properties.They are new photochromic materials.At the same time,benzimidazoles with different carbon chain lengths were also synthesized,and the four molecules had regular host-guest interaction with Q[7]and TMe Q[6].Four kinds of molecules and TMe Q[6] will change regularly under p H regulation,forming four kinds of molecular switches,providing a new idea for the design of cucurbit ring based molecular switches.