Controlling Vilsmeier-Haack processes in meso-methylBODIPYs: A new way to modulate finely photophysical properties in boron dipyrromethenes

In the herein work we report the fine and selective control of competitive processes when submitting meso-methylBODIPYs to Vilsmeier-Haack reaction conditions. These competitive processes generate BODIPYs with opposed photophysical properties, from highly fluorescent dyes enabling laser emission, to non-fluorescent singlet-oxygen photosensitizers. The synthetic control is exerted on the basis of the structure of the starting BODIPY, as well as the electrophilic character (hard or soft) of the formylating reagent.