Synthesis and properties of a new asymmetrical photochromic diarylethene bearing an isoxazole unit

An asymmetrical photochromic diarylethene {1-(3, 5-dimethyl-4-isoxazolyl), 2-[2-methyl-5-(3-cyanophenyl)-3-thienyl]} perfluorocyclopentene (1o), was synthesized, and its electrical and optical properties were also investigated. Diarylethene 1o showed good photochromism in hexane and in PMMA amorphous film. Steady state fluorescence studies indicated that diarylethene 1o has higher fluorescent, but there almost no fluorescence in the closed-ring isomer in hexane. The fluorescence spectra of diarylethene 1o also depended on the concentration. Cyclic voltammetry revealed that great differences existed amongst the electrochemical behaviors between the open-ring isomer and closed-ring isomer of the compound.