TY - JOUR
T1 - ß-Cyclodextrin Host-Guest Complexes Probed under Thermodynamic Equilibrium: Thermodynamics and AFM Force Spectroscopy
AU - Auletta, T.
AU - de Jong, M.R.
AU - Mulder, A.
AU - van Veggel, F.C.J.M.
AU - Huskens, Jurriaan
AU - Reinhoudt, David
AU - Zou, S(han)
AU - Zapotoczny, S.J.
AU - Schönherr, Holger
AU - Vancso, G. Julius
AU - Kuipers, L.
PY - 2004
Y1 - 2004
N2 - The rupture forces of individual host-guest complexes between ß-cyclodextrin (ß-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 ß-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.
AB - The rupture forces of individual host-guest complexes between ß-cyclodextrin (ß-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 ß-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.
U2 - 10.1021/ja0383569
DO - 10.1021/ja0383569
M3 - Article
SN - 0002-7863
VL - 126
SP - 1577
EP - 1584
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
IS - 5
ER -