Triggering a [2]rotaxane molecular shuttle through hydrogen sulfide

A novel chemically-controlled [2]rotaxane molecular shuttle was successfully designed and synthesized. A H2S-responsive bulk barrier was introduced between the two identical recognition stations of the [2]rotaxane to prevent dynamic shuttling of the macrocycle. Upon addition of H2S, the complete intramolecular cascade reaction occurs in a controllable manner, resulting in removal of the bulk barrier and the shuttling motion of the macrocycle between the two stations recovers.