Synthesis, Separation And Supramolecular Self-assembly Of Cyclohexyl Substituted Seven-membered Melon Ring

Cucurbit[n]urils,commonly abbreviated as CB[n] or Q[n],is a new type of highly symmetric barrel macrocyclic molecular in the supramolecular host compounds after cyclodextrin,crown ether and calixarenes.At present,the common family members of the cucurbit[n]urils are Q [5],Q [6],Q [7],Q [8],Q [10],tQ [13],tQ [14] and tQ[15].With the introduction of homologues,derivatives and analogues of cucurbit[n]urils,a series of alkyl-substituted cucurbit[n]urils,cucurbit[n]uril analogues,hemi-cucurbit[n]urils,inverted cucurbit[n]urils,bamboo cucurbit[n]urils have been widely used to improve the solubility and modification of cucurbit[n]urils.It has been extensively concerned by researchers both at home and abroad in recent years,especially in the field of supramolecular self-assembly,and have made remarkable progress because of its specific structures and potential applications.The cucurbit[n]uril has the characteristics of hydrophobic cavity and polar carbonyl modified portal,which not only has the molecular function of the main body,but also the organic molecules with suitable size,forming the unique cucurbit[n]uril host and guest chemistry,and also as the ligand molecular,With the metal ions and their complexes or clusters of coordination,the formation of a unique cucurbit[n]uril coordination chemistry.In recent years,it has been found that the introduction of suitable organic molecules in the cucurbit[n]uril-metal system or the introduction of metal ions in the cucurbit[n]uril-guest molecular system gives a special supramolecular self-assembly with specific properties.In this paper,based on the existing research work,the main contents of this paper are as follows:（1）Synthesis,separation,purification and characterization of cyclohexyl-substituted cucurbit[6]uril and cucurbit[7]uril;（2）the interaction investigation and supramolecular self-assemblies of symmetrical dicyclohexanocucurbit[6]uril with lanthanides show significant differences,which could be used for the isolation of lanthanides;（3）the interaction of symmetrical dicyclohexanocucurbit[6]uril host with p-phenylenediamine guest and its application in wastewater treatment;（4）The interaction of cyclohexyl substituted cucurbit[7]uril host with alkyl（di）ammonium ions and their derivatives and viologen derivatives,namely dialkyl-4,4’-bipyridinium dicationic guests.Based on the outer-surface interaction of cucurbit[n]uril,third species as the structure directing agents was introduced to induce the coordination of the cucurbit[n]uril and metal ions and to interact with the host and guest to construct a supramolecular self-assembly with multi-dimensional and multi-level.For example,in this paper,a symmetrical dicyclohexanocucurbit[6]uril was used to study the interaction with rare earth ions with ZnCl₂ as the structure directing agent under acidic conditions.The "molecular capsule" and the existence of [ZnCl₄]^2-building framework formed by the "honeycomb effect" to promote the formation of cucurbit[n]uril-based one-dimensional supramolecular coordination polymer.The driving force can be attributed to the ion-dipole interaction of the outer-surface of the positively charged cucurbit[n]uril and [ZnCl₄]^2-anion.Due to the positive charge of the outer-surface of the cucurbit[n]uril,attracting [ZnCl₄]^2-anion around the cucurbit[n]uril to form a negatively charged honeycomb structure,it is easy to induce the formation of multi-dimensional multi-level supramolecular self-assembly structure by coordination of metal ions and carbonyl oxygen atoms.