title: Reverse Anomeric Effect in Large-Amplitude Pyridinium Amide-Containing Mannosyl [2]Rotaxane Molecular Shuttles.
abstract: The reverse anomeric effect (RAE) was investigated in different mannosyl [2]rotaxane molecular shuttle isomers that contain dibenzo-24-crown-8 (DB24C8) as the macrocycle, and anilinium and pyridinium amide as molecular stations. The switching on or off of the RAE was possible depending on both the pyridinium amide motif and the localization of the DB24C8 along the thread. The (1) C4 mannopyranosyl chair-like conformation was observed in all the non-interlocked molecules because the anomeric carbon of the mannose is linked to the positively charged nitrogen of the pyridinium unit. In the protonated rotaxanes, the (1) C4 chair conformation of the mannose end remains because the DB24C8 resides around the best anilinium station, which is located at the other end of the axle. Upon deprotonation of the anilinium, the DB24C8 shuttles with a large-amplitude motion toward the pyridinium amide stations, where it interacts in a different fashion depending on the pyridinium motif. In one molecular shuttle, the RAE could be switched on or off with control at one end of the encircled thread upon protonation/deprotonation of the other end, through shuttling of the DB24C8.
authors.affiliation: Supramolecular Machines and ARchitectures Team, Institut des Biomolécules Max Mousseron (IBMM) UMR 5247 CNRS, Université Montpellier, ENSCM, Case courrier 1706, Bâtiment Chimie (17), 3ème étage, Faculté des Sciences, Place Eugène Bataillon, 34095, Montpellier cedex 5, France.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Riss-Yaw
authors.affiliation: Supramolecular Machines and ARchitectures Team, Institut des Biomolécules Max Mousseron (IBMM) UMR 5247 CNRS, Université Montpellier, ENSCM, Case courrier 1706, Bâtiment Chimie (17), 3ème étage, Faculté des Sciences, Place Eugène Bataillon, 34095, Montpellier cedex 5, France.
authors.forename: Philip
authors.initials: P
authors.lastname: Waelès
authors.affiliation: Supramolecular Machines and ARchitectures Team, Institut des Biomolécules Max Mousseron (IBMM) UMR 5247 CNRS, Université Montpellier, ENSCM, Case courrier 1706, Bâtiment Chimie (17), 3ème étage, Faculté des Sciences, Place Eugène Bataillon, 34095, Montpellier cedex 5, France. frederic.coutrot@univ-montp2.fr.
authors.forename: Frédéric
authors.identifier: http://orcid.org/0000-0002-0741-6637
authors.initials: F
authors.lastname: Coutrot
keywords: carbohydrates; conformation analysis; crown compounds; molecular devices; rotaxanes