Synthesis And Properties Of Hemi-cucurbit Rings In Which Glycoside Urea Is Involved

As a supramolecular host,hemicucurbiturils have attracted high attention since2004 when Miyahara et al.gave a report for the first time.During recent years,numerous researchers have prepared multiple kinds of substituted hemicucurbiturils.Meanwhile,the construction of new macrocycles has always been the crucial perspective of supramolecular chemical synthesis.The solubility of hemicucurbituril derivatives in organic solvent is further improved,so they can be applied in aspects,such as reactive catalysis and recognition of molecules and ions.In terms of the modification methods,predecessors mainly adopted semi-glycoluril derivatives and formaldehyde aqueous solution to prepare substituted hemicucurbiturils under acid catalysis conditions.Different from previous modification methods for hemicucurbiturils,this thesis introduces the structural unit of cucurbiturils--glycoluril unit into the hemicucurbiturils,and finally synthesized a novel modified hemicucurbiturils,possessing optical response.Besides,tentative exploration was conducted on the aspects of ions acceptor and guest molecules recognization.The contents of this thesis can be divided into three parts:(1)Synthesis of hemicucurbituril modified with glycoluril:In this thesis,m-dichlorobenzyl chloride,glycoluril unit and semi-glycoluril were selected to construct corresponding fragments,and the target macrocycle were prepared through fragment methods.Besides,the synthesis conditions for segments and macrocycle were optimized,and relatively reasonable synthesis methods were obtained.(2)Exploration of new macrocycles as ions acceptor:The host-guest interaction between macrocycles and several selected anions and metal cations was investigated through UV-VIS absorption spectroscopy and fluorescence spectra.It is discovered that the interaction between modified hemicucurbiturils and iodide ion among selected anions is strong relatively,and presents certain degree of selectivity.Under fluorescence spectra,the host-guest ratio of hemicucurbiturils and Fe³⁺or Cu²⁺in the selected metal cations was measured via Job method.Besides,the detection limit between host and guests was gained through the fluorescence intensity correction curve,and the corresponding stability constant was calculated by fluorescence titration experiment.Through discussing both fluorescence quenching efficiency of guests for host and the fluorescence quenching process,we observe that Fe³⁺and Cu²⁺have selective fluorescence quenching behaviors for the modified hemicucurbituril.(3)Exploration on the host–guest interaction of the novel macrocycle and organic molecules:The host-guest interaction of modified hemicucurbituril and organic molecules,like naphthylamine and naphthol was mainly investigated with the fluorescence spectra.Besides,the host-guest ratio,stability constant,detection limit,fluorescence quenching efficiency and corresponding fluorescence quenching process of macrocycle and the above guests were analyzed via fluorescence titration experiment and Job method.In the fluorescence titration spectrum of macrocycle and naphthylamine or naphthol,we discovered that the fluorescence quenching efficiencies between modified hemicucurbituril and?-naphthylamine or?-naphthol and?-naphthylamine or?-naphthol are different,which can be used to preliminarily differentiate naphthylamine or naphthol of different substituent groups.In addition,the interaction between modified hemicucurbituril and?-naphthylamine shows a greater stability constant and stronger combining capacity,which indicates favorable value on detection of carcinogen.In the aspect of the recognization with phenol derivatives,the novel macrocycle has the strongest combining capacity with p-nitrophenol,and the acidity for the selected phenol derivatives is consistent.Hence,this modified hemicucurbiturils presents relatively good selectivity to p-nitrophenol and potential application on sewage treatment process.