Construction Of Functionalized Nano-supramolecular Assemblies By Cyclodextrins And Their Conjugates

In the thesis,we chose cyclodextrins,cucurbiturils,porphyrins and calixarenes as the basic building blocks to contruct supramolecular functional aggregations and nano reactor container for photochirogeneis,which are summarized as follows:1.A pseudorotaxane was synthesized by reaction of cucurbit uril with 6-[(6-aminohexyl)amino]-6-deoxy-beta-cyclodextrin chloride.Subsequently, pseudorotaxanes were further assembled to form a 2D pseudopolyrotaxane through an alpha,omega-PPG2000 diamino polymer threading the cavities of cyclodextrins,and the resulting pseudopolyrotaxane was comprehensively characterized by FT-IR, NMR,TG-DTA,elemental analysis,and transmission electron microscopy. Significantly,the 2D pseudopolyrotaxane can turn into a main-chain pseudopolyrotaxane in the presence of base,and then the addition of alpha-cyclodextrins may result in a reversible switch between two different 2D pseudopolyrotaxanes.2.2D pseudopolyrotaxanes containing beta-cyclodextrins and cucurbit urils can induce DNA condensation,and the number of cucurbit urils threaded onto the side chains of beta-cyclodextrins plays important roles in this process.3.Tetrakis(permethyl-beta-cyclodextrin)-modified zinc(â…¡) porphyrin(1) and tetra(beta-cyclodextrin)-modified zinc(â…¡) porphyrin(2) were synthesized via "click chemistry".Intermolecular inclusion complexation of these structurally similar 1 and 2 with tetrasodium tetraphenylporphyrintetrasulfonate(3) led to formation of two distinctly different nanoarchitectures with alternate porphyrin and cyclodextrin arrays, which were proven to be network and nanorod aggregates,respectively,by using transmission electron microscopy,atomic force microscopy,and scanning electron microscopy.From the results of comparative studies in different solutions,we elucidated the mechanisms that result in nanorod to network aggregates transition, concluding that the complexation strength of porphyrin with cyclodextrin is a crucial factor to activate the potential binding sites of a molecular building block.4.Two new beta-cyclodextrins(beta-CDs) modified with chromophore were synthesized in high yields through Huisgen 1,3-dipolar cycloaddition.The amount of Cu catalyst was demonstrated to be a key factor that determines the yield of the 1,3-dipolar cycloaddition when applied to CD derivatization.While a catalytic amount of Cu-catalyst is commonly required in conventional click chemistry,more than a half equivalent of Cu catalyst was desirable for obtaining the modified CDs in satisfactory yields.5.Amphiphilic cyclodextrin-calixarene conjugates can self-assembly to form distinctly different aggregations,and the morphology of aggregations critically relys on the polarity and hydrophilicity of solvent.6.Combined use of diamino-γ-cyclodextrin and Cu(ClO₄)₂ achieved the first "catalytic" supramolecular photochirogenesis in the photocyclodimerization of 2-anthracenecarboxylate in aqueous methanol solution at -50℃to give the anti-head-to-head cyclodimer of 70%enantiomeric excess in 52%yield,both of which are the highest ever reported for CD-mediated photochirogenesis.