A novel Br-substituted diarylethene: Synthesis, crystal structure, and solvent dependent acidichromism

A novel Br-substituted diarylethene was synthesized, and its structure has been determined by single-crystal X-ray diffraction analysis. Its photochemical property in solution, a PMMA film, and single crystalline phase was studied. In solution, the absorption maximum of its closed-ring isomer shifted dramatically to shorter wavelengths with notable color change from violet to yellow upon the stimulation of trifluoroacetic acid. Moreover, the acidichromism showed obviously solvent-dependence. With enhancement of solvent polarity, the protonation-induced absorption maxima (Δλ max ) and the response time became longer.