A pH-sensitive lasso-based rotaxane molecular switch.
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 (1)H NMR spectroscopy: the best conditions of self-entanglement were found in the less polar solvent CD(2)Cl(2) 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.
Supramolecular Machines and Architectures Team, Institut des Biomolécules Max Mousseron-UMR CNRS 5247, Université Montpellier 2 et 1, place Eugène Bataillon, case courrier 1706, 34095 Montpellier Cedex 5, France.
Caroline
C
Clavel
Camille
C
Romuald
Emile
E
Brabet
Frédéric
F
Coutrot
D000814:Aniline Compounds / Q000737:chemistry*; D043844:Crown Ethers / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D047028:Macrocyclic Compounds / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008968:Molecular Conformation; D015394:Molecular Structure; D043862:Rotaxanes / Q000138:chemical synthesis* / Q000737:chemistry*; D012997:Solvents / Q000737:chemistry*; D014230:Triazoles / Q000737:chemistry*
D000814:Aniline Compounds; D043844:Crown Ethers; D047028:Macrocyclic Compounds; D043862:Rotaxanes; D012997:Solvents; D014230:Triazoles