A Preliminary Study On The Host-guest Competition Chemistry Between Cucurbital Ring And Calixarene

Cucurbit[n]uril(abbreviated as CB[n]or Q[n])is a new macrocyclic barrel compound that emerged after crown ether,cyclodextrin and calixarene in supramolecular chemistry.The cucurbit[n]uril has a highly rigid symmetrical structure with a hydrophobic cavity and two opening hydrophilic carbonyl portals.cucurbit[n]uril chemistry has become an important branch of supramolecular and macrocycle chemistry due to their novel structural characteristics.According to the structural characteristics and the electropotential properties of the surface of cucurbit[n]urils,related chemistry can be catalogued into three branches:the first one is the Q[n]-based hosts-guest chemistry due to the electrically neutral hydrophobic cavity,which can include various guest molecules;the second one is the Q[n]-based coordination chemistry due to the electro negative carbonyl portals,which can coordinate with metal cations;the third one involves with the positive electropotential outer-surface of cucurbit[n]urils or the Q[n]-based outer surface interaction chemistry,which involves with the interaction with negatively charged substances.The Q[n]-based hosts-guest chemistry has been a mainstream in cucurbit[n]uril chemistry,and the Q[n]-based coordination chemistry become an important branch in cucurbit[n]uril chemistry,the related researches involve with catalysis,polymer chemistry,pharmaceutical chemistry,biochemistry,life sciences,materials and other multidisciplinary.Although the Q[n]-based outer-surface interaction chemistry is an emerging branch in cucurbit[n]uril chemistry,it has involved inadvertently with the researches of the Q[n]-based hosts-guest chemistry and the Q[n]-based coordination chemistry.Along with the in-depth understanding of the research in cucurbit[n]uril chemistry,the Q[n]-based outer-surface interaction chemistry will play an important role in Q[n]-based supramolecular chemistry.In this thesis,the competition chemistry of amantadine hydrochloride with cucurbit[7]uril(Q[7])and sulfonated calix[4]arene(SC[4]A)was first studied.~1H NMR titration experiments were performed to understand interaction mechanism and related interaction models of amantadine hydrochloride with Q[7]and SC[4]A,respectively.Moreover,the ternary system of amantadine hydrochloride with Q[7]and SC[4]A revealed that the interaction of Q[7]with amantadine hydrochloride was stronger than that of SC[4]A with amantadine hydrochloride.On the other hand,it was found that the clear Q[7]solution yield large amount of precipitation immediately by adding clear SC[4]A solution,suggesting that a strong interaction existed between Q[7]and SC[4]A,which become an important research content in this thesis.Cucurbit[n]urils have positive electropotential outer surface,while calixarenes have aromatic rings,therefore they can form stable supramolecular assemblies through the outer surface interaction of cucurbit[n]urils.In this part works,detailed interaction of Q[7]and SC[4]A was investigated by ~1H NMR titration experiments,DOSY experiments(DOSY),dynamic light scattering experiments(DLS),scanning electron microscopes and transmission electron microscopy.The experimental results showed that Q[7]and SC[4]A formed a stable polymer with a ratio of approximately 3:1.Although the crystal structure of the supramolecular assembly based on Q[7]/SC[4]A has not yet been obtained,it can be seen in the image by electron microscopy that there are many pore structures in the assembly,and it is possible to encapsulate and adsorb some molecules.Indeed,Q[7]/SC[4]A-based supramolecular assembly can selectively adsorb some volatile substances or adsorb organic dye molecules with intense fluorescence emission to be solid fluorescent materials.Based on the investigation of interaction system of Q[7]and SC[4]A,another water soluble calixarenesulfonic acid,4-Sulfothiacalix[4]arene(STC[4]A)and Q[7]system was further investigated.First,~1H NMR titration experiments were performed to determine the effect ratio of STC[4]A and Q[7].Fortunately,the single crystals of the Q[7]/STC[4]A-based supramolecular assembly was obtained and the crystal structure was measured by the single crystal X-ray diffractometer.Both methods revealed that the effect interaction ratio of Q7]:STC[4]A was 2:1.Moreover,the adsorption properties of the Q[7]/STC[4]A-based supramolecular assembly for organic dyes were further studied.The experimental results revealed that the Q[7]/STC[4]A-based supramolecular assembly can adsorb some common fluorescent substances,such as levofloxacin,hydroxycoumarin,which can be used to prepare solid fluorescent materials with some potential applications.