Synthesis, Characterization, and Autoreduction of a Highly Electron-Deficient Porphycenatoiron(III) with Trifluoromethyl Substituents

The synthesis of the first fluorine-containing iron porphycenes, 2,7,12,17-tetraethyl-3,6,13,16-tetrakis(trifluoromethyl)porphycenatoiron (III) chloride [FePc(EtioCF3)]Cl and its (mu)-oxo dimer [FePc(EtioCF3)]2O and their characterizations are reported. The crystal structure of [FePc(EtioCF3)]2O displays a severe saddled distortion of the porphycene framework due to the steric and electronic effects of the CF3 substituents. The oxidation and reduction potentials for the (mu)-oxo dimer are significantly more positive compared to those observed for the reference (mu)-oxo dimer of the iron porphycenes and porphyrins having no electron-withdrawing substituent. Moreover, the 1H and 19F NMR spectra of [FePc(EtioCF3)]2O demonstrated that the (mu)-oxo dimer is readily converted into the monomeric ferrous complex in pyridine-d5 through autoreduction for 1 day, although the reduction of the reference iron porphycenes and porphyrins are not observed in pyridine. These results indicate that the trifluoromethylated iron porphycene is a highly electrondeficient complex with a pyrrolic macrocycle ligand.