A pH-Sensitive Lasso-Based Rotaxane Molecular Switch

Authors

  • Dr. Caroline Clavel,

    1. Supramolecular Machines and ARchitectures Team (SMART), Institut des Biomolécules, Max Mousseron (IBMM), –UMR CNRS 5247, Université Montpellier 2 et 1 place Eugène Bataillon, case courrier 1706, 34095 Montpellier Cedex 5 (France), Fax: (+33) 4-67-63-10-46
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  • Dr. Camille Romuald,

    1. Supramolecular Machines and ARchitectures Team (SMART), Institut des Biomolécules, Max Mousseron (IBMM), –UMR CNRS 5247, Université Montpellier 2 et 1 place Eugène Bataillon, case courrier 1706, 34095 Montpellier Cedex 5 (France), Fax: (+33) 4-67-63-10-46
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  • Emile Brabet,

    1. Supramolecular Machines and ARchitectures Team (SMART), Institut des Biomolécules, Max Mousseron (IBMM), –UMR CNRS 5247, Université Montpellier 2 et 1 place Eugène Bataillon, case courrier 1706, 34095 Montpellier Cedex 5 (France), Fax: (+33) 4-67-63-10-46
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  • Dr. Frédéric Coutrot

    Corresponding author
    1. Supramolecular Machines and ARchitectures Team (SMART), Institut des Biomolécules, Max Mousseron (IBMM), –UMR CNRS 5247, Université Montpellier 2 et 1 place Eugène Bataillon, case courrier 1706, 34095 Montpellier Cedex 5 (France), Fax: (+33) 4-67-63-10-46
    • Supramolecular Machines and ARchitectures Team (SMART), Institut des Biomolécules, Max Mousseron (IBMM), –UMR CNRS 5247, Université Montpellier 2 et 1 place Eugène Bataillon, case courrier 1706, 34095 Montpellier Cedex 5 (France), Fax: (+33) 4-67-63-10-46
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Abstract

The synthesis of a pH-sensitive two-station [1]rotaxane molecular switch by self-entanglement of a non-interlocked hermaphrodite molecule, containing an anilinium and triazole moieties, is reported. The anilinium was chosen as the best template for the macrocycle benzometaphenylene[25]crown-8 (BMP25C8) and allowed the self-entanglement of the molecule. The equilibrium between the hermaphrodite molecule and the pseudo[1]rotaxane was studied by 1H NMR spectroscopy: the best conditions of self-entanglement were found in the less polar solvent CD2Cl2 and at high dilution. The triazole moiety was then benzylated to afford a benzyltriazolium moiety, which then played a dual role. On one hand, it acts as a bulky gate to trap the BMP25C8, thus to avoid any self-disentanglement of the molecular architecture. On another hand, it acts as a second molecular station for the macrocycle. At acidic pH, the BMP25C8 resides around the best anilinium molecular station, displaying the lasso [1]rotaxane in a loosened conformation. The deprotonation of the anilinium molecular station triggers the shuttling of the BMP25C8 around the triazolium moiety, therefore tightening the lasso.

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