A New Approach to the Synthesis of meso-CN-Substituted BODIPYs

A preparative synthetic procedure to the meso-CN substituted BODIPY has been developed. This method is based on the addition of KCN to the borondipyrromethene moiety of the meso-unsubstituted molecules in the presence of a crown ether with further oxidation with Pb(OAc)4. The CN group at this position causes an essential bathochromic shift in absorption/emission and influence on other physicochemical properties of borondipyrromethenes over a wide range.