Fluorescent probes based on a tetrad BODIPY structure for detection of a wide range of water contents in organic solvents

A series of tetrad Boron dipyrromethene (BODIPY) derivatives containing a variety of nitrogen-heterocyclic meso-substituents were synthesized. All exhibited fluorescence enhancement in the presence of water in organic solvents. Water-soluble tetrad BODIPY derivatives were obtained by displacement of fluoride at the boron atom by a bicyclic structure, and their fluorescence response was observed over a wide range of water contents in various organic solvents. The presence of acids or metal ions induced only a fluorescence shift and retained the fluorescence efficiency.