A Photochromic Diarylethene Bearing a Six-Membered Aryl Unit

A new unsymmetrical photochromic diarylethene compound 1a was synthesized and its photochromism were investigated, such as photochromism and kinetics in solution. The compound exhibited good photochromism in solution with alternating irradiation by UV/Vis light, and the maxima absorption of its closed-ring isomer 1b are 515nm. The open-ring isomer of the diarylethene 1a exhibited relatively strong fluorescence at 424 nm when excited at 280 nm. Its fluorescence intensity decreased along with the photochromism from open-ring isomers to closed-ring isomers upon irradiation with 297 nm UV light.