Azulene as an ingredient for visible-light- and stimuli-responsive photoswitches
The azulene molecule features a unique combination of optical, luminescence, and stimuli-responsive properties. This makes the azulene motif a promising functional group to be introduced in photoswitches. Recent challenges in the field of photochromic compounds require the development of new approaches to molecules that are switched by visible light (400–760 nm), are proton responsive and have advanced luminescent properties. Merging azulene with photoswitches opens prospects for fulfilling these requirements. Herein, we highlight recent results on the application of this hydrocarbon motif in various photochromic systems, such as stilbenes, diarylethenes, and azobenzenes.