Coumarin-diene photoswitches for rapid and efficient isomerization with visible light.

We have developed 7-diethylaminocoumarin-based chromophores that photoisomerize with visible light. These photoswitches possess many desirable attributes, including large extinction coefficients (18 600-59 100 M-1 cm-1), high quantum yields (0.45-0.50) and resistance to photofatigue. Additionally, time-resolved spectroscopy indicates that both isomerization reactions are complete in less than 1 ns.