Synthesis Of Several Kinds Of Cyclodextrin Derivatives And The Study On The Interaction Of Host And Guest Molecules

Cyclodextrin chemistry is an important part of supramolecular chemistry,and the amphiphilic cyclodextrins,a kind of oligomer with a taper cylinder,are consisted of glucopyranose units linked by ?-1,4 glucosidic bonds.Possessing a hydrophobic cavity and a hydrophilic tube,cyclodextrins have a significant ability to form host-guest supramolecules with a wide variety of small organicor inorganic molecules,so that they have present potential applications as drug carriers,enzyme models,and food additives.However,the structure of natural cyclodextrin molecules is rigid that can not be topologically changed when interacted with guest molecules,which resuled from the fact that hydrogen bonds are easily formed between the hydroxyl groups of cyclodextrin.Therefore,the modification of cyclodextrins has been the priority among the cyclodextrin chemical studies.There are two categories are divided among the methods for selective modification of cyclodextrin:(1)primary face modification,including mono-substitution,di-substitution and per-substitution at the 6-position of cyclodextrins respectively;(2)secondary face modification,including both mono-substitution and per-substitution at the 2-position of cyclodextrins.In this paper,seven kinds of mono-substituted derivatives and per-substituted derivatives were synthesized viamono-[6-O-6-toluenesulfonyl]-?-cyclodextrin and per-[6-deoxy-6-chloro]-?-cyclodextrin respectively.Moreover,the ultraviolet-visible spectroscopy(UV),fourier transform infrared spectroscopy(FT-IR),proton nuclear magnetic resonance spectroscopy(1H-NMR),X-ray diffraction(XRD),and the rmogravimetri analysis(TGA)were used to characterize the products,such as cyclodextrins modified by 4-alkoxydiphenyl acid,mono-[6-deoxy-6-ethylenediamine]-?-cyclodextrin,cyclodextrin modified by 2,4-dihyoxybenzoicacid,mono-[6-deoxy-6-S-pyridyl]-?-cyclodextrin,per-[6-deoxy-6-S-pyrimidyl]-?-cyclodextrin,per-[6-deoxy-6-S-pyridyl]-p-cyclodextrin and per-[6-deoxy-6-thiol]-?-cyclodextrin.The molecular structure and self-assembly behavior of per-[6-deoxy-6-chloro]-?-cyclodextrinwas measured by X-ray crystallography,the approximate sevenfold axis and round shape of ?-cyclodextrin is not significantly changed when replaced with chlorine atoms at the primary side,while the thermostability is decreased withhydrogen bonds vanishing.And the moleculars of per-[6-deoxy-6-chloro]-?-cyclodextrin formed linear superstructure by the head-to-head interactions and the tail-to-tail interactionsformed from the Cl-Cl interaction and hydrogen bonds respectively.