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Synthesis and fluorescence switching of a photochromic diarylethene bearing fluorine atoms

A new photochromic diarylethene, 1-(2,4-dimethyl-5-thiazolyl)-2-[5-(2,4-difluorophenyl)-2-methyl-3-thienyl]perfluoro-cyclopentene(1a), has been synthesized. its photochromic and fluorescent properties have been investigated in detail. The results showed that this compound exhibited reversible photochromism, changing from colorless to red after irradiation with UV light both in solution and in PMMA amorphous film. In hexane, the open-ring isomer of the diarylethene 1a exhibited relatively strong fluorescence at 433 nm when excited at 305 nm. The fluorescence intensity decreased along with the photochromism upon irradiation with 297 nm light and its closed-ring isomer showed weak fluorescence. Finally, photomode rewritable optical storage using 1b was performed. The images demonstrated that the compound can be used as optical storage material.