Preparation and characterization of multi-cationic BODIPYs and their synthetically versatile precursors

We report the synthesis and characterization of a family of mono-, di- and tri-cationic boron dipyrromethene (BODIPY) dyes and their versatile precursors using convenient and high yielding synthetic procedures. The distyryl substituted precursors for the cationic target molecules presented in this study allow for further functionalization in a variety of ways, and are promising starting materials for further synthetic development of BODIPY dyes. The fluorescent, red-absorbing di- and tri-cationic dyes are well soluble in water and polar organic solvents and offer possibilities for fluorescence marking in biochemistry, photodynamic therapy, chemical sensing and other aqueous applications. The introduction of a pyridine substituent in the meso position of the BODIPY allows for control over fluorescence properties and offers the future possibility for the development of novel coordination complexes. This combination of properties allows these BODIPY derivatives to be possible building blocks for multi-purpose functional materials.