β-cyclodextrin host−guest complexes probed under thermodynamic equilibrium: thermodynamics and AFM force spectroscopy

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DOI	Trouver le DOI : https://doi.org/10.1021/ja0383569
Auteur	Rechercher : Auletta, Tommaso; Rechercher : de Jong, Menno R.; Rechercher : Mulder, Alart; Rechercher : van Veggel, Frank C. J. M.; Rechercher : Huskens, Jurriaan; Rechercher : Reinhoudt, David N.; Rechercher : Zou, Shan; Rechercher : Zapotoczny, Szczepan; Rechercher : Schönherr, Holger; Rechercher : Vancso, G. Julius; Rechercher : Kuipers, Laurens
Format	Texte, Article
Résumé	The rupture forces of individual host−guest complexes between β-cyclodextrin (β-CD) heptathioether monolayers on Au(111) and several surface-confined guests were measured in aqueous medium by single molecule force spectroscopy using an atomic force microscope. Anilyl, toluidyl, tert-butylphenyl, and adamantylthiols (0.2−1%) were immobilized in mixed monolayers with 2-mercaptoethanol on gold-coated AFM tips. For all guests and for all surface coverages, the force−displacement curves measured between the functionalized tips and monolayers of β-CD exhibited single, as well as multiple, pull-off events. The histograms of the pull-off forces showed several maxima at equidistant forces, with force quanta characteristic for each guest of 39 ± 15, 45 ± 15, 89 ± 15, and 102 ± 15 pN, respectively. These force quanta were independent of the loading rate, indicating that, because of the fast complexation/decomplexation kinetics, the rupture forces were probed under thermodynamic equilibrium. The force values followed the same trend as the free binding energy ΔG° measured for model guest compounds in solution or on β-CD monolayers, as determined by microcalorimetry and surface plasmon resonance measurements, respectively. A descriptive model was developed to correlate quantitatively the pull-off force values with the ΔG° of the complexes, based on the evaluation of the energy potential landscape of tip−surface interaction.
Date de publication	2004-02-01
Maison d’édition	American Chemical Society
Dans	Journal of the American Chemical Society 126, nº 5 : 1577–1584.
Langue	anglais
Publications évaluées par des pairs	Oui
Publication du CNRC	Cette publication n’est pas du CNRC Ce sont des publications qui ont été rédigées par un auteur du CNRC, mais avant que celui-ci soit employé du CNRC.
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Identificateur de l’enregistrement	8f394ca4-c0d2-4380-a4f2-4ad09a32c825
Enregistrement créé	2019-04-12
Enregistrement modifié	2020-05-30

Date de modification :: 2024-07-17