Spectroscopic Studies of Phenyl Iron(IV) Porphyrin Complexes and Their Conversion into Iron(II) N-Phenylporphyrins

Article abstract of DOI:10.1021/ja00270a018

Oxidation of phenyl iron(III) tetraarylporphyrin complexes with bromine in chloroform at -60 deg C produces deep-red solutions whose 1H and 2H NMR spectra indicate that they are the corresponding iron(IV) complexes.Characteristic 1H NMR resonances include pyrrole protons at -60 to -70 ppm, iron phenyl resonances at ca. -300 ppm for the ortho protons, -50 to -75 ppm for the meta protons, ca. -100 ppm for the para protons, and ca. +110 ppm for the para-methyl protons.The magnetic susceptibility of the iron(IV) species is 2.6 +/- 0.4 μ_B.These aryl iron(IV) complexes are thermally unstable.When warmed, the aryl iron(IV) complex undergoes a clean reductive elimination to form the iron(II) complex of the N-arylporphyrin.The electronic structure of the S = 1 iron(IV) complexes is consistent with an orbital occupany d_xy²d_xz¹d_yz¹ with ?-spin density transferred to the porphyrin and the axial phenyl group.