Efficient Synthesis, Photochromism and Fluorescence Properties of a Novel Diarylethene Bearing a Naphthalene

A new unsymmetrical photochromic diarylethene compound 1a was synthesized and its photochromism were investigated. The compound exhibited good photochromism in solution and PMMA films with alternating irradiation by UV/Vis light, and the maxima absorption of its closed-ring isomer (1b) are 536 nm in hexane and 552 nm in PMMA films. The open-ring isomer of the diarylethene 1a exhibited relatively strong fluorescence at 441 nm when excited at 290 nm. Its fluorescence intensity decreased along with the photochromism from open-ring isomers to closed-ring isomers upon irradiation with 297 nm UV light.