Five-state molecular switching of a [3]rotaxane in response to weak and strong acid and base stimuli.

This communication describes the base- and acid-induced five-state translational isomerization of a [3]rotaxane containing two pairs of N-arylamine and N-alkylamine centers as binding sites for two dibenzo[24]crown-8 components. Gradual molecular shuttling of this [3]rotaxane is achieved in response to both the amount and strength of the added acid or base.