A Lockable Light‐Driven Molecular Shuttle with a Fluorescent Signal

A turn on! A lockable photodriven molecular shuttle is based on a [2]rotaxane that consists of an α-cyclodextrin threaded by a stilbene derivative. The fluorescent signals originate from the naphthalimide stopper and indicate the position of the shuttle. Once unlocked, the device can be turned on by irradiation at 335 nm and turned off by irradiation at 280 nm. The shuttle can be locked or unlocked by the addition acid or alkali, respectively (see picture).