A Novel β-cyclodextrin dimer,2,2′-o-phenylenediseleno-bridgedbis（β-cyclodextrin）（2）,has been synthesized by reaction ofmono-[2-O-（p-tolylsulfonyl）]-β-cyclodextrin and poly（o-phenylenediselenide）.The complexation stability constants（Ks）and Gibbs free energy changes（-ΔG°）of dimer 2 with fourfluorescence dyes,that is,ammonium 8-anilino-1-naphthalene-sulfonate（ANS）,sodium 6-（p-toluidino）-2-naphthalenesul-fonate（TNS）,Acridine Red（AR）and Rhodamine B（RhB）have been determined in aqueous phosphate buffer solution(pH=7.2,0.1 mol·L-1at 25℃ by means of fluorescence spec-
A novel modified cyclodextrin, mono[6-O-6-(4- carboxyl-phenyl)]-b-CD (1), has been synthesized by the reaction of mono[6-(p-toluenesulfonyl)]- b-CD with 4-hydro- xybenzoate, and its molecular self-assembly behavior in both solution and solid state was studied by means of crystallography, NMR spectroscopy and microcalorimetry. The results indicate that the bezoic acid groups are successively penetrated intermolecularly into the adjacent b-CD cavities to form helical columnar supramolecules in the solid state. As compared with crystal, the similar self-assembly behavior of 1 in aqueous solution has also been confirmed by the 1H ROESY spectroscopy. Thermodynamically, the formation of polymeric supramolecules by modified CD in aqueous solution is mainly driven by entropy changes.
FAN Zhi, ZHAO Yanli & LIU Yu Department of Chemistry, State Key Laboratory of Elemento-Organic Chemistry, Nankai University, Tianjin 300071, China Correspondence should be addressed to Liu Yu (e-mail: yuliu@public. tpt.tj.cn)
The self-assembly behavior of mono(6-phenolic-6-deoxy)-β-cyclodextrin bothin solution and the solid state is comparatively studied by X-ray crystallography and ~1H NMRspectroscopy. The results obtained show that the phenolic groups in the crystal 1 can successivelypenetrate into the adjacent β-cyclodextrin cavities from the secondary side to form head-to-taillinear polymeric su-pramolecule with a 2-fold screw axis. The self-assembly behavior also can bedetermined in D_2O solution, giving a self-association constant of 240 mol^(-1)·L. Using thepresent and previous structures reported for the relevant β-cyclodextrin derivatives, i.e.,mono(6-anilino-6-deoxy)-β-cyclodextrin, mono(6-phenylselenyl-6-deoxy)-β-cyclodextrin, andmono(6-phenylthio-6-deoxy)-β-cyclodextrin, we further reveal the factors governing the formationsof supramolecular assemblies.
