X-ray crystallographic study on single-crystalline photochromism of bis(2,5-dimethyl-3-thienyl)perfluorocyclopentene

The single-crystalline cycloreversion reaction of a photochromic diarylethe ne, bis(2,5-dimethyl-3-thienyl)perfluorocyclopentene, was studied by X-ray single-crystal structure analysis. The single crystal of the closed-ring fo rm isomer was irradiated with 680 nm light and formation of the open-ring f orm isomer was followed. The crystal structure analysis revealed that the c ycloreversion reaction proceeded in the single crystal in a conrotatory mod e.