New photochromic 1,2-diarylperfluorocyclopentenes bearing unsymmetrical six-membered aryl units

A new class of unsymmetrical photochromic diarylethenes based on the six-membered naphthalene-benzene and naphthalene-pyridine backbones has been firstly developed and their properties have been discussed. The two different six-membered aryl moieties were connected directly to the central cyclopentene ring and available to participate in the photoinduced cyclization reaction. The three diarylethenes exhibit distinctly different photochromism by photoirradiation in solution: they turn red, yellow, and orange upon photocyclization, which may be resulted from the different substituent and six-membered aryl moiety effects. Compared with the analog bearing a benzene unit, diarylethene bearing a pyridine moiety has a shorter absorption maximum and a smaller fluorescent quantum yield, and it shows a dual-addressable photo-switch by photoirradiation and acid/base stimulation.