Synthesis And Properties Of Partially Methyl-substituted Cucurbit[6]uril

Cucurbit[n]urils are among the macrocyclic receptors in supramolecular chemistry known to date besides crown ether, cyclodextrins and calixarene. Cucurbit[n]urils have been the subject of much interest in recent years because of their structural specialties and their potential applications as functional materials. Usually, cucurbit[n]urils are insoluble in water and organic solvents. They can only dissolve in strong acid such as formic acid, acetic acid and hydrochloric acid, which strong restrict their application and further investigations. Therefore, synthesis of modified cucurbit[n]urils has become an important research task of cucurbit[n]urils researchers. In this paper, two kinds of partially methyl-substituted cucurbiturils were synthesized through the dimethyl-substituted glycoluril dimer. Furthermore, a series of complexes based on partially methyl-substituted cucurbituril have been prepared by the self-assembly of partially methyl-substituted cucurbituril with correspongding metal ions.At first, on the basis of literature review, the first chapter of this thesis described the origin, structure character and application prospect of cucurbit[n]urils in details. Then, the synthesis and modification of cucurbit[n]urils derivatives were summarized. At last, the research content and significance of this paper were briefly introduced.In the second chapter, a dimethyl-substituted glycoluril dimer and two kinds of partially methyl-substituted cucurbit[6]uril, the symmetrical octamethyl-substituted cucurbit[6]uril and o-tetramethyl substituted cucurbit[6]uril, were synthesized. Their structures were characterized by NMR spectroscopy and single-crystal X-ray diffraction.In the third chapter, the host-guest interaction between the symmetrical octamethyl-substituted cucurbit[6]uril and 2,2’-bipyridine hydrochloride was investigated by NMR, UV and ITC. The inclusion ratio, stability constants, entropy and enthalpy of the inclusion complex were discussed.In the fourth chapter, two coordination complexes of the o-tetramethyl substituted cucurbit[6]uril with alkaline earth metal ions(Ca2+、Sr2+) were obtained and charactered by single-crystal X-ray diffraction.In the fifth chapter, eleven coordination complexes of the o-tetramethyl substituted cucurbit[6]uril with lanthanide metal ions(Nd3+、Sm3+、Eu3+、Gd3+、Tb3+、Dy3+、Ho3+、Er3+、Tm3+、Yb3+、Lu3+) were obtained and characterized by single-crystal X-ray diffraction. Due to the o-tetramethyl substituted cucurbit[6]uril with the light lanthanide metal ions(La3+、Ce3+、Pr3+) couldn’t form a solid crystal, a means of isolation of the heavier lanthanides metal ions from their lighter counterparts was studied by elemental analysis.