The Modified Cucurbiturils - Methyl-substituted Synthesis Cucurbiturils, Isolation And Nature Study

Cucurbit[n]uril has been an important part of supermolecule field in these years. The cucurbiturils are potentially as useful as well-known host molecules such as crown ethers, cyclodextrins(CDs). Their host-guest chemistry as well as supramolecular assemblies based on Q[n] has been studied and summarized in a topical review article. However, the poor solubility in common solvents has limited development of the chemistry of cucurbit[n]uril. Thus, synthesis of Q[n] derivatives that allow them to dissolve in both aqueous systems and common organic solvents., have received greatest attention .Recently, a number of fully and partially substituted Q[n] have been reported. These include the fully substituted (cyclohexano.CyH) (CyH)₂Q[5] and (CyH)₂Q[6], Me₁₂Q[6] and (HO)_2nQ[n] and the partially substituted Ph₂Q[6], Me₆Q[6], Me₄Q[6] and (Me₂CyP)_nQ[6],We report the synthesis of a series of cucurbit—tetrasubstituted cucurbit[6](TMeQ[6]), disubstitutedcucurbit[5](DMeQ[5]), hexasubstituted cucurbit[5] (HMeQ[5]) and substitutedcucurbit[7] (Me_nQ[7]) by using the diether of dimethylglycoluril and dimmer of glycoluril in this thesis.This series of substitutedcucurbit[n] have been determined by ¹H NMR spectroscopy and ESMS. And the particular elliptical structure of TMeQ[6] has been further confirmed by single crystal X-ray diffraction. TMeQ[6] , DMeQ[5] , HMeQ[5] and Me_nQ[7] showed surprising water solubility, which allowed us to investigate the properties in neutral water. Some substituted Methylcucurbit[5]urils have been syntesised and isolated, they are characterized by ¹H NMR spectroscopy, mass spectra and single crystal X-ray diffraction analysis. Experimental results reveal that the structure of the Q[5]s influence on their solubility, and which is related with dipole moment from chemical calculation. The solubility is Me₆Q[5]> Me₂Q[5]> Me₁₀Q[5]> Q[5].And then selected common metal ions and benzimidazole derivatives as the title guests to discuss the interaction mechanism between cucurbit and guest and the structures of the self-assembling molecular complex by using X-ray diffraction analysis, NMR techniques, UV-vis Spectroscope and Fluorescence Spectroscope. . X-ray diffraction analysis shows the whole structure of the crystal contains a complicated system of hydrogen bonds including all structural units of the crystal. If omitting all hydrogen bonds and strontium ions, a "molecular tube" and molecular filter can be observed.