Hydroxy groups enhance [2]rotaxane anion binding selectivity

15 February 2022, Version 1
This content is a preprint and has not undergone peer review at the time of posting.


We report the synthesis of two [2]rotaxanes containing an interlocked three dimensional binding cavity formed from a pyridinium bis(amide) axle component containing two phenol donors, and an isophthalamide based macrocycle. In the competitive solvent mixture 1:1 CDCl3:CD3OD, one of the receptors exhibits a much higher selectivity preference for chloride than an analogous rotaxane without the hydroxy groups. X-ray crystal structures reveal the chloride anion guest encapsulated within the interlocked binding cavity, though not all of the hydrogen bond donors are utilised. Computational semiempirical simulations indicate that secondary intermolecular interactions occur between the axle hydroxy hydrogen bond donors and the [2]rotaxane macrocycle components, contributing to a more preorganised binding pocket, which may be responsible for the observed enhanced selectivity.


supramolecular chemistry
anion binding

Supplementary materials

Supporting Info for hydroxy rotaxane paper
Your standard Supporting Information. 80-odd pages of NMR spectra, computational details and other goodness.


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