Photoswitching Materials

Photoswitchable materials are mainly engineered from molecules that are capable of undergoing reversible changes in their intrinsic properties through the use of light as an external stimulus. As the absorption properties of most of these molecules change reversibly with photoexcitation, most of them are also photochromic materials. Many of these photoswitching processes operate through reversible chemical transformations, such as trans-cis isomerization, ionization, pericyclic ring-opening and ring-closing reaction, and intramolecular group transfer reaction. Through systematic investigations and subsequent rational designs on the photochromic frameworks using the state-of-the-art organic synthetic methodologies, the photochromic properties could be modified, tuned, and tailored for molecular switching. In this chapter, different photochromic families and selected recent works dealing with the functionalization of different families of photochromic molecules for the photoswitching of luminescent behavior, electronic communication, optical properties, molecular shuttling, and host-guest interaction are described. © 2012 John Wiley & Sons, Ltd. All rights reserved.