Triggering a [2]Rotaxane Molecular Shuttle by a Photochemical Bond-Cleavage Strategy

The successful triggering of ring-shuttling motion between two stations in a [2]rotaxane is demonstrated by employing a photochemical bond-cleavage strategy. A photolabile bulk barrier is covalently introduced into two identical stations of the thread to prevent dynamic shuttling of the Macrocycle, resulting in a gated state. Irradiation of UV light (lambda = 365 nm) results in the complete removal of the bulk barrier and the balanced shuttling motion of the macrocycle, indicating an open state of the rotaxane. In addition, the process from the open rotaxane to the gated rotaxane was executed by a chemical-rebonding method.