Aza boron-pyridyl-isoindoline isomers: synthesis and photophysical properties

By changing benzo-fused position on pyridyl unit, three aza boron-pyridyl-isoindoline isomers, a new type of BODIPY analog, are synthesized through a facile two step reaction. These isomers show broad envelopes of intense vibrational bands in the absorption and emission spectra with moderate fluorescence quantum yields. In comparison to those of classical BODIPYs, significant fluorescence intensity are observed for these isomers in film and powder. An analysis of the structure-property relationships has been carried out based on X-ray crystallography, optical spectroscopy, and theoretical calculation.