Photochemistry Properties of a Novel Photochromic Diarylethene Derivative

A new unsymmetrical photochromic diarylethene, 1-[2, 4-dimethyl-5-thiazolyl]-2-[2-methyl-5-(3-methylphenyl)-3-thienyl]perfluorocyclopentene(lo) were synthesized, and its properties, such as photochromism in solution as well as in poly-methylmethacrylate (PMMA) amorphous films, and fluorescence properties were investigated in detail. The results showed the compound exhibited good photochromism in hexane solution and in PMMA amorphous film, the maxima absorption of its closed-ring isomer 1c are 492 nm and 498 nm respectively. The open-ring isomer of the diarylethene 1 exhibited relatively strong fluorescence at 465 nm in hexane solution (5 x 10(-5) mol/L) when excited at 289 nm. The fluorescence intensity decreased along with the photochromism upon irradiation with 297 nm light. The fluorescence intensity of diarylethene lo also depended on the concentration. When the concentration of diarylethene lo 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.