title: Role of the Methoxy Groups in Cryptophanes for Complexation of Xenon: Conformational Selection Evidence from129Xe-1H NMR SPINOE Experiments.
abstract: We report the laser-polarized129Xe and1H NMR spectra of a series of cryptophane derivatives that differ only by the number of methoxy groups attached on their benzene rings and the syn or anti arrangement of the linkers (compounds 6 a-s, 9 a-s, 12 a-s). All these compounds bind xenon even though the characteristic signal of the gas encapsulated in the cavity of the cage-molecule cannot always be detected. Interestingly, the exchange dynamics of xenon strongly depends on the degree of substitution and is different from that of the cryptophane derivatives studied previously. In solution, the1H NMR spectra of these derivatives show the presence of different conformations in a slow exchange regime that can be explained by a decrease of the flexibility of their skeleton. Thanks to129Xe-1H dipolar cross-relaxation (SPINOE) spectra, we demonstrate that a single conformation present in solution can bind xenon.
authors.affiliation: NIMBE, CEA, CNRS, Université de Paris Saclay, CEA Saclay, 91191, Gif-sur-Yvette, France.
authors.forename: Patrick
authors.initials: P
authors.lastname: Berthault
authors.affiliation: NIMBE, CEA, CNRS, Université de Paris Saclay, CEA Saclay, 91191, Gif-sur-Yvette, France.
authors.forename: Céline
authors.initials: C
authors.lastname: Boutin
authors.affiliation: NIMBE, CEA, CNRS, Université de Paris Saclay, CEA Saclay, 91191, Gif-sur-Yvette, France.
authors.forename: Estelle
authors.initials: E
authors.lastname: Léonce
authors.affiliation: Centre de Diffractométrie Henri Longchambon, Université de Lyon 1, 5 rue la Doua, 69100, Villeurbanne, France.
authors.forename: Erwann
authors.initials: E
authors.lastname: Jeanneau
authors.affiliation: Laboratoire de Chimie de L'ENS LYON (UMR 5182), Ecole Normale Supérieure de Lyon, 46, Allée D'Italie, 69364, Lyon cedex 07, France.
authors.forename: Thierry
authors.identifier: http://orcid.org/0000-0001-9746-4706
authors.initials: T
authors.lastname: Brotin
keywords: NMR spectroscopy; SPINOE; cryptophanes; hyperpolarized xenon; molecular recognition