Synthesis and photophysical properties of thiolactone derivatives

A class of bis-thiolactone derivatives is prepared by photo-conversion of photochromic diarylethenes with a bis (5-chloro-2-methylthiophen-3-yl) system in moderate yields (50–60%). Bis-thiolactone derivatives show fluorescence in solution with moderate fluorescent quantum yields (0.11–0.17). Reaction mechanism exhibits that the photo-conversion of diarylethenes to bis-thiolactone derivatives undergoes a two-step reaction: photocyclization and photo-oxidation.