Dipyrromethene Dyes

　Dipyrromethene is a unit structure of porphyrin and can coordinate to main group elements and transition metals as a monoanionic bidentate ligand to form complexes. Among them, a dipyrromethene-coordinated boron complex (boron dipyrromethene) shows a very small Stokes shift, high fluorescent quantum efficiency that is independent of solvent polarity, large molar absorption coefficient, and sharp excitation and emission spectra. It is expected that dipyrromethene dyes are alternative fluorescent dyes to fluorescein and rhodamine dyes. Applications of dipyrromethene dyes are fluorescent labeling reagents, laser dyes, and electronic materials. A chemical modification of boron dipyrromethene controls optical properties more easily than other fluorescent dyes.