Regulation of Macrocycle Shuttling Rates in [2]Rotaxanes by Amino‐Acid Speed Bumps in Organic–Aqueous Solvent Mixtures
Maxime Douarre, Vicente Martí‐Centelles, Cybille Rossy, Isabelle Pianet, Nathan D. McClenaghan
Abstract
A homologous series of two‐station [2]rotaxanes incorporating amino‐acid units in the molecular thread has been developed. The degenerate [2]rotaxanes exhibit amino‐acid specific shuttling rates between two fumaric stations related to the steric factor associated to the amino‐acid side chain, as demonstrated by variable‐temperature 1 H NMR spectroscopy and exchange spectroscopy (EXSY). This allows tuning of the macrocycle shuttling rate over 4 orders of magnitude, which has a relatively small solvent dependency.
Topics & Concepts
ChemistrySteric effectsSolventNuclear magnetic resonance spectroscopyHomologous seriesSpectroscopySolvent effectsSteric factorPolymer chemistryPhotochemistryDegenerate energy levelsTwo-dimensional nuclear magnetic resonance spectroscopyKineticsSeries (stratigraphy)Solvent polarityComputational chemistryMoleculeUltraviolet visible spectroscopyOrganic chemistryPhysical chemistryStereochemistrySupramolecular Chemistry and ComplexesSynthesis and Properties of Aromatic CompoundsDendrimers and Hyperbranched Polymers