Regulation of macrocycle shuttling in [2]rotaxanes by amino-acid speed bumps in organic-aqueous solvent mixtures
arXiv:2012.08458 · doi:10.1002/ejoc.202000997
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 1H NMR spectroscopy and exchange spectroscopy (EXSY). This allows tuning of the macrocycle shuttling rate over 4 orders of magnitude, which further has a relatively small solvent dependency.
7 figures; supplementary information appended