CHEMICAL COMMUNICATIONS, v.49, no.48, pp.5453 - 5455
Abstract
The UV-induced photocyclization of a dithienylethene-annulated N-heterocyclic carbene precatalyst enabled photoswitchable ring-opening polymerizations of epsilon-caprolactone and delta-valerolactone. The polymerizations proceeded efficiently in ambient light, however UV irradiation attenuated the reaction rate (k(amb)/kUV = 59). Subsequent visible light exposure reversed the photocyclization and restored catalytic activity.