Study On The Supermolecular Self-assembly Of Ten-membered Cucurbit Ring And Its Performance

Cucurbit[n]uril?Q[n]?chemistry has now become an important part of macrocyclic chemistry and supramolecular chemistry.Along with the development of cucurbit[n]uril chemistry,apart from in terms of host-guest chemistry,cucurbit[n]uril showed excellent properties in the field of supramolecular materials.This paper set about coordination chemistry of cucurbit[n]uril and conducted a series of studies,in order to examined three types of coordination patterns:1)based on outer surface interaction supramolecular self-assembled of the pure Q[n]s,2)induced by metal ions with the outer surfaces interaction supramolecular self-assembly of Q[n]s,3)the aromatic compounds with the outer surfaces interaction of Q[n]s.Based on these three modes and constructed of seven non-fluorescent porous supramolecular framework materials,then take advantage of its porosity and absorbability,sequentially loaded with a series of small organic molecules with no or weak fluorescence,the fluorescence intensity was increased and the fluorescent material was prepared.Finally,the fluorescent material is used to adsorb formaldehyde,pyridine,benzene and other volatile gases,and the fluorescence is significantly enhanced and quenched.It is used as a fluorescent indicator of formaldehyde and pyridine gas.Firstly,the mixture of cucurbit[n]uril was synthesized by paraformaldehyde and glycoside as raw materials,then the Q[5],Q[6],Q[7],Q[8]and Q[10]was obtained by filtration,deacidification,recrystallization and column chromatography.Utilizing the characteristic that the number of glycoside units is odd,the solubility is good,and the even number is poor,for Q[6]and Q[10]were recrystallized,and different crystal materials were obtained under different media,concentrations,temperatures,and induction reagents.Secondly,the material is used to adsorb different small organic molecules to improve its optical properties,and be converted into fluorescent materials.Finally,the fluorescent material was used to adsorb and detect toxic and harmful gases such as formaldehyde and pyridine,and a series of studies were studied on its adsorption and optical properties.The experiments in this paper are mainly divided into the following categories:1)The Q[10]formed a layered supramolecular material SOF-1 under the condition of 6M hydrochloric acid solution,and the weakly fluorescent compound8-hydroxyquinoline was loaded in SOF-1 in acetonitrile solution to obtain an SOF-1@8-hydroxyquinoline assembly.The optical properties are improved about 40 times than individual 8-hydroxyquinoline,and the assembly is used to respond to the pyridine gas,and the fluorescence quenching occurs quickly.2)the Q[10]formed a layered supramolecular material SOF-2 under the condition of 3M nitric acid solution,and was loaded with ofloxacin and naphthalene,respectively.The fluorescence was red-shifted and quenched,and then responded to benzene,ethanol,tetrahydrofuran and pyridine.The fluorescence enhancement and redshift phenomenon occurred respectively.3)The Q[10]was induced by[Cd Cl₄]^2-to form a three-dimensional tubular metal organic framework material MOF-1,and which has loaded with the organic molecule dansyl chloride was used to obtain a non-fluorescent assembly,the assembly absorbs pyridine gas,the fluorescence intensity is greatly improved,and it is used as an indicator of pyridine gas.4)The Q[10]was induced by[Zn Cl₄]^2-to form a three-dimensional hole-shaped metal organic framework material MOF-2,and which has loaded with the weakly fluorescent molecule 1,8-diaminonaphthalene was used to obtain the strong fluorescent assembly MOF-2@1,8-diaminonaphthalene,the assembly can specifically recognize formaldehyde gas,fluorescence intensity quenched 19.55 times,and the detection limit can reach 0.09 mg/m³;5)The Q[10]was induced by Nd³⁺to form a three-dimensional tubular metal organic framework material MOF-3 and its structure was characterized.6)Q[6]in 3M HCl hydrochloric acid solution under the induction of sulfonated calix[4,6]arene to form supramolecular organic framework material SOF-3 and SOF-4,respectively.Which were used to load cationic pink and ethyl red to make fluorescent sensors can be used to detect formaldehyde and pyridine gas,respectively.