Synthesis of Porphyrinoids, BODIPYs, and (Dipyrrinato)ruthenium(II) Complexes from Prefunctionalized Dipyrromethanes

Abstract

The introduction of functional groups into the mesoposition of dipyrromethanes, boron-dipyrromethenes (BODIPYs) and porphyrinoids, is of fundamental importance in designing such dye systems for material sciences or photomedicine. One route that has proven to be particularly useful in this respect is the nucleophilic aromatic substitution (SNAr) on porphyrinoids and their precursors carrying electron-withdrawing substituents. To further expand this methodology, the potential of the 4-fluoro-3-nitrophenyl and the 3,4,5-trifluorophenyl moieties for the synthesis of functionalized dipyrromethanes, BODIPYs, and porphyrinoids has been evaluated. The 3,4,5-trifluorophenyl moiety proved not to be applicable in the SNAr with nucleophiles. The introduction of the 4-fluoro-3-nitrophenyl group, however, allowed fast and efficient SNAr with various amine nucleophiles. The synthesized 4-amino-3-nitrophenyl-substituted dipyrromethanes were successfully applied in the synthesis BODIPYs and were tested in the synthesis of ‘trans’-A2B2 porphyrins and A2B corroles. Furthermore, the dipyrromethanes - after oxidation to the dipyrromethenes - were found to be suitable ligands for metal ions giving access to functionalized ruthenium(II) metal complexes.