Rigid, Bistable Molecular Shuttles Combining T-shaped Benzimidazolium and Y-shaped Imidazolium Recognition Sites

Two different recognition sites, one a T‐shaped 2,4,7‐triphenylbenzimidazolium and the other a Y‐shaped 2,4,5‐triphenylimidazolium are combined to construct a rigid bistable [2]rotaxane molecular shuttle on which the position of a 24‐membered crown ether macrocycle can be controlled by acid–base chemistry. Molecular shuttling in both the neutral and dicationic versions were studied. The wheel deal: A combination of T‐shaped benzimidazolium and Y‐shaped imidazolium recognition sites are incorporated into a single axle of a [2]rotaxane to create a bistable molecular shuttle that can be driven by changes in pH.