Synthesis and Optical Property of an Asymmetric Photochromic Diarylethene Derivative Bearing Benzofuran

A new asymmetric photochromic diarylethene bearing a benzofuran unit was synthesized, namely [1-(2-methyl-3-benzofuranyl)-2-(2-methoxyphenyl)]perfluorocyclopentene (lo). Its photochromic and fluorescent properties were investigated, respectively. The compound exhibited reversible photochromism, changing from colorless to red upon irradiation with UV light both in solution and in PMMA film. The diarylethene exhibited relatively strong fluorescence at 410 nm in hexane solution and 462 nm in PMMA amorphous film when excited at 300 and 385 am, respectively. The fluorescence intensity decreased along with the photochromism both in hexane and PMMA film upon irradiation with 297 nm light.