Photocyclization Reaction of Diarylethene−Perylenebisimide Dyads upon Irradiation with Visible (>500 nm) Light

Two types of fluorescent diarylethene−perylenebisimide dyads were synthesized and their photochromic performance was studied. The dyads showed an unexpected photochromic reactivity. The photocyclization reaction takes place upon irradiation with visible light (>500 nm), where the diarylethene unit has no absorption. Inferring from the excitation wavelength dependence and oxygen effect, the triplet states of the diarylethene unit are considered to play an essential role in the photocyclization reaction with visible (>500 nm) light.