A ratiometric near-infrared pH-responsive fluorescent dye based on distyryl BODIPY

A novel distyryl boron dipyrromethene substituted with two 4-(dimethylamino)phenylethynyl groups at the 2- and 6-positions has been synthesised and characterised. It exhibits remarkable and reversible pH-responsive changes in the absorption and fluorescence emission spectra, both in organic and in aqueous media.