Synthesis and Properties of A Novel Photochromic Diarylethene 1-(2,4-dimethyl-5-thiazolyl)-2-[2-methyl-5-(4-formylphenyl)-3-thienyl]perfluorocyclopentene

A new unsymmetrical photochromic diarylethene, 1-(2, 4-dimethyl-5-thiazolyl)-2-[2-methyl-5-(4-formylphenyl)-3-thienyl]perfluorocyclopentene (1o) were synthesized. At the same time, its photochromic properties and fluorescence switch were investigated in detail. The results showed 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 of closed-ring isomer 1c were observed at 501 nm in hexane and at 510 nm in PMMA amorphous film, respectively, upon irradiation with 297 am UV light. The open-ring isomer of the diarylethene 1 exhibited relatively strong fluorescence at 449 nm in hexane solution (2 x 10(-5) mol/L) and 450 nm in PMMA amorphous film when excited at 300 nm and 292 nm, respectively. The fluorescence intensity decreased along with the photochromism upon irradiation with 297 nm light. The fluorescence intensity of diarylethene 1o also depended on the concentration. When the concentration of diarylethene 1o in hexane increase from 1 x 10(-6) mol/L to 2 x 10(-4) mol/L, the fluorescence intensity of the open-ring isomer become strong first, then become weak.