Many molecules can be switched between different states using light. These reversible photochemical reactions are typically unimolecular processes, such as the trans-cis isomerization of azobenzenes or the ring opening/closing of dithienylethenes. Anthracene derivatives are unusual in that they can act as bimolecular photoswitches. For example, irradiation of anthracene with visible or near-UV light yields dianthracene (right), which in turn can be broken apart to using either light or heat.
Are work focuses on finding new ways to control these bimolecular photoswitches, and incorporating these photochromic groups into functional materials.