Photochromic, Kinetics, and Fluorescence of A Novel Diarylethene

A new unsymmetrical photochromic diarylethene, 1-(2-ethyl-3-benzofuranyl)-2-(2,5-dimethyl-3-thienyl)perfluorocyclopentene (1) was synthesized, and its photochromic properties and kinetics of the photochromic cyclization/cycloreversion were investigated. The results showed that the cyclization/cycloreversion process of these compounds were determined to be the zeroth/first order reaction.The compound exhibited good photochromism in hexane solution with alternating irradiation by UV/Vis light, and the maxima absorption of its closed-ring isomer 1c are 502 nm. The open-ring isomer of the diarylethene 1 exhibited relatively strong fluorescence at 402 nm in hexane solution (2 x 10(-5) mol/L) and 412 nm in PMMA amorphous film when excited at 312 nm and 310 nm,respectively. The fluorescence intensity decreased along with the photochromism upon irradiation with 297 nm light and its closed-ring isomer showed almost no fluorescence. The fluorescence spectra of diarylethene 1o depended on the concentration.