Host-guest Interaction And Property Research Between Cycl Opentyl Cucurbit[6]uril And Aromatic Nucleus

Cyclopentyl Cucurbit[6]uril?Cy P6Q[6]?as a relatively new member of cucurbit structure,the asymmetry caused by cyclopentyl structure at the waist makes its solubility much higher than that of common cucurbit,and more methylene on the outer wall makes cyclopentyl cucurbit ring have higher activity,which means that Cy P6Q[6]has greater research value than that of common cucurbit.However,due to the low yield of Cy P6Q[6]and the high price of raw materials,there are not many studies on Cy P6Q[6].In this experiment,we mainly studied the interaction of Cy P6Q[6]with phenanthroline derivatives and other fluorescent groups,and explored the change of optical properties of the whole system after the interaction between them.At the same time,some aromatic small molecules were selectively introduced into the cucurbit ring metal self-assembly system to explore new types of aromatic small molecules.The main contents of this paper include the following three partsFirst,the host–guest interactions between Cy P6Q[6]and a series of2-?Ar?-1H-imidazo[4,5-f][1,10]phenanthroline hydrochloride salts?i.e.Ar-IPHS,where Ar=3-pyridyl,phenyl,2-thienyl,p-F-phenyl and 4-N,N-dimethylphenylamino?were studied using nuclear magnetic resonance titration,ultraviolet absorption spectroscopy,fluorescence absorption spectroscopy and single crystal X-ray diffraction.The study found that Cy P6Q[6]and Ar-IPHS can exhibit two interaction modes:1)Some groups of Ar-IPHS enter the cavity of the cucurbituril and interact with Cy P6Q[6]in a 1:1 ratio and 2)Ar-IPHS interacts with the portal carbonyl oxygen atoms in Cy P6Q[6]via hydrogen bonding,Van der Waals interactions,etc.It was found that the optical properties of some groups of Ar-IPHS change after entering the cavity of Cy P6Q[6],especially in an aqueous phase.a fluorescent probe Ar-IPHS@Cy P₆Q[6]was prepared to identify amino acids by utilizing the property that Cy P₆Q[6]can make Ar-IPHS produce strong fluorescence.The experimental results showed that the probe can efficiently identify glycine,lysine,and methionine,with detection limit of 2.270x10^-6mol/L,1.359x10^-5mol/L,and 1.690x10^-5mol/L,respectively.The small organic molecules,such as p-phenylenediamine?g1?,benzidine?g2?,4,4'-diaminostilbene dihydrochloride?g3?,were added,P-hydroxybenzoic acid?g4?,p-nitrophenol?g5?,hydroquinone?g6?these six small organic molecules were introduced into[Cd Cl₄]^2--cyp6q[6]system.g1,g2,g3,these three aromatic diamine organic small molecules mainly connect the two ports of the melon ring,thus acting as the linker between the ports of the melon ring and making the Cy P6Q[6]connect with each other.[Cd Cl₄]^2-plays an induction role in the outer wall of Cy P6Q[6]to form various kinds of assemblies.g4,g5 and g6,the three aromatic alcohol organic small molecules,together with[Cd Cl₄]^2-,act on the outer wall of the Cy P6Q[6]and promote the assembly and accumulation of the Cy P6Q[6]in different forms.Compared with these six crystals,it is found that the change of one group of organic small molecules and the increase or decrease of one carbon chain will have a huge impact on the final assembly.Driven by hydrogen bond,electrostatic action,hydrophobic action and van der Waals force,aromatic small molecules and melon ring constructed special supramolecular assemblies.These new supramolecular self-assembly structures have great potential applications in separation,catalysis and Optoelectronics.