New Insight into the Fatigue Resistance of Photochromic 1,2-Diarylethenes

Photochromic diarylethenes represent one of the most important classes of molecular switches, and their fatigue resistance is reported in several papers. Previous studies have demonstrated that the presence of perfluorocyclopentene and methyl in the 4-positions of dithienylethenes improve the switching resistance. However, general guidelines to correlate chemical structure to fatigue resistance have not been found yet. In this work, we provide a different thought in the description of the fatigue resistance of diarylethenes, which is related to the light absorbed by the two isomeric states during photoconversion. For two series of 1,2-diarylethenes, which differ from the aromatic rings without bearing any electroactive substituent, it turns out that the fatigue resistance depends on the dose of light absorbed by the colored form rather than on the specific molecular structure, namely, the presence of specific molecular building blocks.