title: Active Esters as Pseudostoppers for Slippage Synthesis of [2]Pseudorotaxane Building Blocks: A Straightforward Route to Multi-Interlocked Molecular Machines.
abstract: The efficient synthesis and very easy isolation of dibenzo[24]crown-8-based [2]pseudorotaxane building blocks that contain an active ester motif at the extremity of the encircled molecular axle and an ammonium moiety as a template for the dibenzo[24]crown-8 is reported. The active ester acts both as a semistopper for the [2]pseudorotaxane species and as an extensible extremity. Among the various investigated active ester moieties, those that allow for the slippage process are given particular focus because this strategy produces fewer side products. Extension of the selected N-hydroxysuccinimide ester based pseudorotaxane building block by using either a mono- or a diamino compound, both containing a triazolium moiety, is also described. These provide a pH-dependent two-station [2]rotaxane molecular machine and a palindromic [3]rotaxane molecular machine, respectively. Molecular machinery on both interlocked compounds through variation of pH was studied and characterized by means of NMR spectroscopy.
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: Thibaut
authors.initials: T
authors.lastname: Legigan
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: Caroline
authors.initials: C
authors.lastname: Clavel
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: crown compounds; kinetics; molecular machines; rotaxanes; thermodynamics