Photochromism, Kinetics and Fluorescence of 1-(2-methyl-3-benzofuranyl)-2-[2-methyl-5-(4-cyanophenyl)-3-thienyl]perfluorocyclopentene

An unsymmetrical photochromic diarylethene compound, 1-(2-methyl-3-benzofuranyl)-2-[2-methyl-5-(4-cyanophenyl)-3-thienyl]perfluorocyclopentene was synthesized, and its photochromic properties, kinetics of the photochromic cyclization/cycloreversion and fluorescence were investigated in detail. The compound exhibited good photochromism, changing from colorless to red after irradiation with 297 nm UV light, in which absorption maxima were observed at 530 nm in hexane solution. Simultaneously, cyclization/cycloreversion kinetics of this diarylethene was researched. The open-ring isomer of the diarylethene exhibited relatively strong fluorescence at 377 nm in hexane solution (2 x 10(-5) mol L-1), when excited at 327 nm. The fluorescence intensity decreased along with the photochromism upon irradiation with 297 rim light. The fluorescence spectra of the diarylethene are depended on the concentration.