Oxygenation Patterns for Iron(II) Porphyrins. Peroxo and Ferryl (FeIVO) Intermediates Detected by 1H Nuclear Magnetic Resonance Spectroscopy during the Oxygenation of (Tetramesitylporphyrin)iron(II)

Article abstract of DOI:10.1021/ja00337a022

The reaction between unligated (tetramesitylporphyrin)iron(II) (TMPFe^II) and dioxygen in a toluene solution has been examined by 1H NMR spectroscopy.At -70 deg C, TMPFe^II reacts with O2 to yield TMPFe^IIIOOFe^IIITMP that has spectroscopic properties similar to those of other peroxo-bridged complexes.On warming, TMPFe^IIIOOFe^IIITMP decomposes to yield a second intermediate (identified as TMPFe^IVO) and TMPFe^IIIOH, the final, stable product.TMPFe^IIIOOFe^IIITMP reacts with N-methylimidazole (N-MeIm) to produce (N-MeIm)TMPFeO2 and (N-MeIm)2TMPFe^II.The former has been independently prepared from (N-MeIm)2TMPFe^II and dioxygen at -50 deg C. TMPFe^IVO reacts with N-MeIm to form (N-MeIm)TMPFe^IVO that has been identified by comparison with other Fe^IVO complexes.TMPFe^IVO reacts with triphenylphosphine at -50 deg C to yield triphenylphosphine oxide while TMPFe^IIIOOFe^IIITMP is unreactive toward triphenylphosphine under these conditions.TMPFe^II is a catalyst for the oxidation of triphenylphosphine by dioxygen. 1H NMR spectra and resonance assignments for each species are described.