Photoinduced Autonomous Nonequilibrium Operation of a Molecular Shuttle by Combined Isomerization and Proton Transfer Through a Catalytic Pathway.

We describe a [2]rotaxane whose recognition sites for the ring are a dibenzylammonium moiety, endowed with acidic and H-bonding donor properties, and an imidazolium center bearing a photoactive phenylazo substituent. Light irradiation of this compound triggers a network of E / Z isomerization and proton transfer reactions that enable autonomous and reversible ring shuttling away from equilibrium.