Synthesis, Photochromism Properties of a Hybrid Diarylethene with a Six-Membered Aryl Unit

A unsymmetrical diarylethene derivative 1-(2 trifluoromethylphenyl)-2-[2-methyl-5-(4-methoxylphenyl)-3 thienyl]hexafluorocyclopentene (la) was synthesized. At the same time, its photochromic properties and fluorescence switch were investigated in detail. The results showed that this compound exhibited reversible photochromism, undergoing reversible cyclization and cycloreversion reactions upon alternating irradiation with UV and visible light both in solution and in PMMA film, and its absorption maxima were observed at 546 nm in hexane and at 571 nm in PMMA amorphous film, respectively, upon irradiation with 297 nm UV light. The fluorescence intensity of diarylethene decreased dramatically along with the photochromism from open-ring isomer to closed-ring isomer upon irradiation with 297 nm UV light in PMMA film. In PMMA film, the open-ring isomer of the diarylethene 1 exhibited relatively strong fluorescence at 468 nm when excited at 395 nm. The electrochemcial switching property can be potential use for electrochemistry data storage. This new photochromic compound also exhibited remarkable optical storage character.