We report quantum efficiencies for the ring-opening reaction of a diarylethene-based photochromic molecular switch (DAE1) following one- and two-photon excitation with a femtosecond pulsed laser. The reaction is pictured in the figure below.  The compound, 1,2-bis(2,4-dimethyl-5-phenylthiophene-3-yl)perfluorocyclopentene, changes from a transparent open-ring isomer to a purple-colored closed-ring isomer upon exposure to visible light. We directly monitor the extent of conversion through the change in visible absorbance under irradiation with the pulsed laser. One-photon excitation at 375 nm, 500 nm, and 600 nm converts DAE1-closed to DAE1-open with quantum yields of F1PA= 0.072 � 0.008, F1PA = 0.077 � 0.008, and F1PA = 0.051 � 0.006, respectively. Excitation with two photons at 750 nm also induces the ring-opening reaction, with an estimated yield ofF2PA= 0.10 � 0.04.

Quantum yields for one- and two-photon cycloreversion of a photochromic molecular switch

247th National Meeting (2014)

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