Synthesis and Properties of a Novel Photochromic Diarylethene Bearing Methyl Group

A new unsymmetrical photochromic diarylethene 1-(2,4-dimethyl-3-isoxazol)-2-[2-methyl-5-(2-methyl)-3-thienyl]perfluorocyclopentene (1a) has been synthesized. Its photochromic properties in solution and PMMA film were investigated. Diarylethene 1a changed the color from colorless to pink upon irradiation with 297 nm UV light, in which absorption maxima were observed at 518 nm in hexane and at 527 nm in PMMA film, respectively. In hexane solution, the open-ring isomer of the diarylethene 1 exhibited relatively fluorescence at 386 nm when excited at 309 nm.