Study On Separation Of 14th Ring And Its Supramolecular Self - Assembly

Cucurbit[n]urils (commonly abbreviated as Q[n]s or CB[n]s) are among themacrocyclic receptors known to date besides crown ethers, cryptands, cyclodextrins,and calixarenes, including cucurbit[5]urils (Q[5]s), cucurbit[6]urils (Q[6]s),cucurbit[7]urils (Q[7]s), cucurbit[8]urils (Q[8]) and cucurbit[10]urils (Q[10]s) incucurbit[n]uril family. The improment of synthesis and separation methods lead toappearance of a series of cucurbit[n]uril derivatives with novel structures andproperties, such as the inverted cucurbit-[6]uril and inverted cucurbit[7]uril (iQ[6] andiQ[7]), the chiral nor-seco-cucurbituril (±)-bis-ns-Q[6], and the nor-seco-cucurbit[10]-uril (ns-Q[10]).Based on the former works, the investigations in this thesis includes three prats:1) Synthesis, separation and characterization of a new novel cucurbit[n]uril, thetwisted cucurbit[14]uril (tQ[14]);2) The interaction investigation and supramolecularself-assemblies of lanthanides to tQ[14], and the interaction investigation of tQ[14]with organic molecular;3) Construction of Q[8]-based coordination complexes andsupramolecalr coordination polymers and investigation of their potential applicationin separation linght lanthanides from heavy light lanthanides.Twisted Cucurbit[14]uril is a new member of the cucurbit[n]uril family. As it hasa twist cavity, our naming as tQ[14]. The discovery of tQ[14] send us the mostimportant information that larger oligomers and the correspondingcucurbit[n>10]urils could exist in processes of a normal Q[n]-synthesis. This paperintroduces the synthesis and separation methods of the new cucurbit[n]urils,characterized the largest cucurbit[14]uril and investigated the supramolecularself-assemblies which are induced by inorganic molecules with tQ[14]. Using NMRtechniques, UV-vis absorption spectroscopy and fluorescence spectroscopy, westudied the interaction of tQ[14] with organic molecular. we summarized manyspecial properties of tQ[14], such as the structure flexibility, it could be adjusted bybinding to organic molecules or metal ions; good solubility in water and organicsolvents (DMSO, DMF); the portal size of tQ[14] is larger than those of Q[5] and Q[6], but smaller than those of Q[7] and Q[8]. and so on. More detailed host-guestchemistry and coordination chemistry of the tQ[14] are undergoing in our laboratory.The coordination and supramolecular assemblies of Q[8] with lanthanides in thepresence of [CdCl4]2–anions show significant differences, which could be used for theisolation of light lanthanides from their heavier counterparts. We have investigatedthe coordination of Q[8] molecules with a series of Ln3+cations based on X-raydiffraction analysis, have revealed that the presence of [CdCl4]2–anions results in theformation of two different supramolecular assemblies, which are the first examples ofQ[8]-based coordination frameworks in the presence of an inorganic species as astructure inducer. Moreover, the different crystal growing period and crystallinityoffer a possible means of isolating the light lanthanide cations from their heaviercounterparts. Several typical Ln3+light-Ln3+heavy-Q[8]-[CdCl4]2systems were selectedand the electron spectroscopy of the crystals measured. All these systems show highratios Lnlight3+/Lnheavy3+. That shows useful information for isolating the lightlanthanide cations from their heavier counterparts. We continue to carry out furtherdetailed investigations aimed at developing a practically useful technique.