1,7-Dithienyl BODIPYs: do thienyls outperform phenyls?

Abstract

For the synthesis of NH, α-CH pyrroles, nitrostyrene-based approaches were explored, including the Gómez-Sánchez and Grob–Camenish methods. A modified Grob–Camenish procedure enabled the preparation of several NH, α-CH pyrroles bearing electron-rich arene substituents that are inaccessible by other routes. From the corresponding thiophene-substituted pyrrole, the respective 1,7-dithienyl BODIPY dyes were synthesized and subjected to post-functionalization. The resulting thiophene-substituted chromophores were investigated by X-ray diffraction, electronic absorption and fluorescence spectroscopy, and quantum-chemical calculations, and their properties were compared with those of the phenyl-substituted analogues.