Showing papers by "Mohamed Eddaoudi published in 1995"

Divalent Cation-Cyclodextrin Interactions at the Air-Water Interface. A Three-Stage Process

Abstract: The interaction, at the air-water interface, between heptakis-6-O-(dimethyl-tert-butylsilyl)-β-cyclodextrin and calcium chloride has been studied using Langmuir isotherms and surface potential measurements. The results show that at CaCl 2 concentrations below 5×10 -3 M there is coordination of the Ca 2+ cations with bridging of cyclodextrin units leading to a more compact and stable monolayer and a decrease in apparent molecular area from 278 to 257 A 2 . For Ca 2+ concentrations between 5×10 -3 and 5×10 -2 M there is further coordination at the macrocyclic rim with inclusion of the anion accompanied by monolayer expansion and a decrease in monolayer stability. For CaCl 2 concentrations above 5×10 -1 M there is inclusion of the cation with expulsion of anions and water from the macrocyclic cavity as shown by large changes in the surface potential and by the lack of change in apparent molecular area

Tailoring Cyclodextrins for the Construction of Large Scale Molecular Assemblies

Abstract: The Cyclodextrins are a class of “off-the-shelf” [1] molecular hosts prepared by the enzymatic degradation of amylose by the enzyme CGTase. Their molecular dimensions, symetry and general shape as truncated cones are schematised below in Figure 1.