Synthesis and properties of directly linked corrole–ferrocene systems

Abstract

Meso-substituted corroles bearing directly linked ferrocene unit have been synthesized for the first time. Among various methods studied, only the condensation of pentafluorophenyldipyrromethane with a formylferrocene led to this type of product. A triad containing corrole and porphyrin bridged with ferrocene has been obtained by a convergent approach. Bilanes were used as crucial substrates in the porphyrin-forming step. For the first time it was shown that H₂O–MeOH–HCl conditions are suitable for preparation of various 10-(formylaryl)corroles via the direct condensation of aromatic dialdehydes with dipyrromethanes. Electrochemical studies of 10-ferrocenyl-5,15-bis(pentafluorophenyl)corrole support the possibility of intramolecular electron transfer from the corrole to the ferrocene system after the electrode oxidation of the ferrocene to a ferrocenium cation. We have studied the structure of 1-(corrolyl)-1′-(porphyrinyl)ferrocene by ¹H NMR and UV-Vis. NMR spectra show that this compound has more conformational freedom than analogous, previously studied bis-porphyrinylferrocenes. Absorption spectra suggest the lack of strong electronic interaction between ferrocene and porphyrinoids for dyads and significant conjugation for the triad.