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

M. Eddaoudi; A. Baszkin; H. Parrot-Lopez; M. M. Boissonnade; A. W. Coleman

doi:10.1021/la00001a004

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

M. Eddaoudi, A. Baszkin, H. Parrot-Lopez, M. M. Boissonnade, A. W. Coleman^*

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

24 Scopus citations

Abstract

The interaction, at the air—water interface, between heptakis-6-O-(dimethyl-iert-butylsilyl)-β-cyclodextrin and calcium chloride has been studied using Langmuir isotherms and surface potential measurements. The results show that at CaCl₂ concentrations below 5 x 10^-3 M there is coordination of the Ca²⁺ 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 A². For Ca²⁺ concentrations between 5 x 10^-3 and 5 x 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 CaCl₂ concentrations above 5 x 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.

Original language	English (US)
Pages (from-to)	13-15
Number of pages	3
Journal	LANGMUIR
Volume	11
Issue number	1
DOIs	https://doi.org/10.1021/la00001a004
State	Published - Jan 1 1995
Externally published	Yes

ASJC Scopus subject areas

General Materials Science
Condensed Matter Physics
Surfaces and Interfaces
Spectroscopy
Electrochemistry

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10.1021/la00001a004

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title = "Divalent Cation-Cyclodextrin Interaciions at the Air-Water Interface. A Three-Stage Process",

abstract = "The interaction, at the air—water interface, between heptakis-6-O-(dimethyl-iert-butylsilyl)-β-cyclodextrin and calcium chloride has been studied using Langmuir isotherms and surface potential measurements. The results show that at CaCl2 concentrations below 5 x 10-3 M there is coordination of the Ca2+ 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 A2. For Ca2+ concentrations between 5 x 10-3 and 5 x 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 CaCl2 concentrations above 5 x 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.",

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AU - Eddaoudi, M.

AU - Baszkin, A.

AU - Parrot-Lopez, H.

AU - Boissonnade, M. M.

AU - Coleman, A. W.

PY - 1995/1/1

Y1 - 1995/1/1

N2 - The interaction, at the air—water interface, between heptakis-6-O-(dimethyl-iert-butylsilyl)-β-cyclodextrin and calcium chloride has been studied using Langmuir isotherms and surface potential measurements. The results show that at CaCl2 concentrations below 5 x 10-3 M there is coordination of the Ca2+ 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 A2. For Ca2+ concentrations between 5 x 10-3 and 5 x 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 CaCl2 concentrations above 5 x 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.

AB - The interaction, at the air—water interface, between heptakis-6-O-(dimethyl-iert-butylsilyl)-β-cyclodextrin and calcium chloride has been studied using Langmuir isotherms and surface potential measurements. The results show that at CaCl2 concentrations below 5 x 10-3 M there is coordination of the Ca2+ 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 A2. For Ca2+ concentrations between 5 x 10-3 and 5 x 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 CaCl2 concentrations above 5 x 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.

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

Abstract

ASJC Scopus subject areas

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