Synthesis, Separation And Supramolecular Self-assembly Of Methyl Hydroxy Substituted Melon Rings

Cucurbit[n]urils are highly symmetric macrocycles with two identical carbonyl-laced portals and a hydrophobic cavity which constructed from n glycolurils bridged by 2n methylene groups(commonly abbreviated as Q[n] or CB[n]). Q[n]s are excellent ligands because of their unique structures consisting of two polar portals rimmed with carbonyl groups, and Q[n]–chemistry gradually becom an important area in the supramolecular chemistry. Since Q[6] was characterized by X-ray diffraction,much attention have been devoted to the synthesis of new members in recent years,including Q[5], Q[6], Q[7], Q[8], Q[10], tQ[14] and a variety of substituted cucurbit[n]uril derivatives with novel structures and properties. Amongst them are certain substituted Q[n] derivatives, which are soluble in common solvents and amenable to functionalization, making great progresses in constructing supramolecular assemblies based on these substituted Q[n] derivatives.Hemimethyl-substituted cucurbit[n]urils are made from a refluxing system containing 3?-methylglycoluril, paraformaldehyde and HCl, and are characteristic of1) the cheapest ones with the highest yield; 2) containing large cucurbit[n]urils(n ? 7);3) dissolving in both water and organic solvent; 4) high stability, such as high yield of oxidation products. Moreover, almost no one investigates the hemimethyl-substituted cucurbit[n]urils and their chemistry. Thus, based on the previous works, the reseaches of this thesis focus on: i) synthesis, separation and characterization of hemihydroxylated hemimethyl-substituted cucurbit[n]urils(HHQ[n]s); ii)investigation of the interaction and supramolecular self-assemblies of HHQ[n]s with alkaline-earth metal cations(AE2+) and lanthanide cations(Ln3+) which could be used for the isolation of lanthanides from their lingter or heavier conternents; iii)HMeQ[6]-based porous supramolecular frameworks for highly selective absorption for volatile compounds(VOCs); iv) host–guest complexation of HMeQ[7] with benzimidazole-drug molecules, which could be used for the enhancement of solubility for benzimidazole-drug molecules.Q[n]-based supramolecular assemblies could be designed and constructed in thepresence of the third species as structure directing agents through the “out-surface interactions” of Q[n]s have became a new branch in Q[n]-chemistry. Bsaed on above theory a series of novel HMeQ[n]-based supramolecular architectures have been constructed, and these assemblies could have potential applications in selective absorption for volatile compounds(VOCs), isolation of lanthanides from their lingter or heavier conternents, enhancement of solubility for drug molecules and so on, these investigations further enrich the content of Q[n]-chemistry.