The first comparative study of the ability of different hydrophilic groups to water-solubilise fluorescent BODIPY dyes

A green-emitting BODIPY dye carrying a carboxylic acid at the meso-phenyl ring was derivatised with a set of eight different hydrophilic groups neutral, negatively- or positively-charged at physiological pH. The determination of both partition coefficient (log P) and fluorescence quantum yield (ΦF) for each polar BODIPY dye allows building the first water-solubility scale for such fluorescent organic materials. This valuable tool can be used to select the most suitable molecular candidate for converting a hydrophobic BODIPY scaffold into a water-soluble and brightly fluorescent dye, and for tuning its net electric charge/polarity according to the biolabelling application targeted for this specific fluorescent marker.