New Insights into the Exploitation of BODIPY Derivatives as Organic Photocatalysts

Boron-dipyrromethene complexes (BODIPYs) are attracting a growing interest for their notable photophysical properties. Specifically, their application in organic photocatalysis is receiving particular attention thanks to their ability to undergo both electron and energy transfer processes, thus acting as promising photoredox catalysts and photosensitizers. Although the number of examples employing these organic dyes is constantly increasing, there are not so many studies that correlate their chemical composition to their photocatalytic activity. In this work, a rationally designed structure-activity relationship study was performed by selecting a synthetically relevant atom transfer radical addition (ATRA) reaction as a benchmark. We demonstrated how the presence of heavy atoms in the chromophore’s core turned out to be essential for achieving high reactivity levels. On the contrary, electron-withdrawing groups in position 8 (meso) undermined the catalytic performances, in agreement with the proposed reaction mechanism.