Adjustable Photochromic Behavior of a Diarylethene-Based Bistable [3]Rotaxane

An acid–base stimulus-responsive diarylethene-based bistable [3]rotaxane has been constructed through a threading-stoppering method, manifesting a reversible shuttling motion undergoing acid–base stimulation. In this system, two macrocycles can be driven to unfasten or restrict the photoswitchable framework by addition of the appropriate acid or base, revealing that photocyclization quantum yield of the [3]rotaxane in the "Near" state is superior to that in the "Far" state. These findings offer a new approach for directional improvement of photochromic performance and construction of molecular machine with a shuttling motion.