Application Of Water-Soluble Cavitands In Molecular Recognition And Cyclization Reaction

Calixarene is the third generation of supramolecular compound that has the advantages of crown ether and cyclodextrin.Due to its adjustable hydrophobic cavities,it can selectively identify and bind cations,anions and neutral molecules.Therefore,calixarene has broad application prospects in some fields of molecular recognition sensing,organic catalysis,drug delivery systems and nanomaterials,etc.when modified with water-soluble functional groups by the synthetic method,water-soluble cavitand show excellent properties.Furtherly,this dissertation mainly focus on application of water-soluble cavitands in molecular recognition and cyclization reaction.The details are as follow:In the first part,we successfully achieve the goal of synthesis of large amount of watersoluble cavitand 1,and learn about the molecular recognition between water-soluble cavitand 1 and cycloalkane derivatives.We analyze the conformation and motion of cyclohexyl halides in the cavity of cavitand 1 firstly,then we study the host-guest complex between cavitand 1 and 2-methylisoborneol(2-MIB),finally we expect cavitand 1 will apply to the purification of drinking water in the future.In the second part,we design and synthesize a new water-soluble cavitand 2.It is characterize by NMR,mass spectroscopy and other detection method.The study indicates that cavitand 2 show the existence of multiple conformations-“vase”,“kite”,“velcrand” in different deuterated solvents.Except that,we prepare the host-guest complex between cavitand 2 and cycloalkanes and carboxylic acid,and demonstrate water-soluble cavitand 2 has deeper hydrophobic cavity when compare with cavitand 1.In the third part,we study the molecular recognition of water-soluble cavitand 1 and alkyl dithiols,and then realize the intramolecular reaction of alkyl dithiols to yield cyclic disulfides in cavity.Then add excess Tri(2-carboxyethyl)phosphine hydrochloride(TCEP)to the reacted system,the cyclic disulfides are not reduced to dithiols by cavitand 1’s protection.Watersoluble cavitand 1 acts as a vehicle that promotes reaction in aqueous and behaves as a protecting container that protect unstable S-S bond of product.