Spin coupling in distorted high-valent Fe(IV)-porphyrin radical complexes

M. Müther*, E. Bill, A. X. Trautwein, D. Mandon, R. Weiss, A. Gold, K. Jayaraj, R. N. Austin

*Corresponding author for this work
12 Citations (Scopus)


In order to study structural influences on the interaction of Fe(IV) (S=1) and porphyrin cation radical (S′=1/2) in high-valent iron porphyrin complexes of the type |X-(TMP)Fe=O|+(Cl-), X=I, Br2, Br4 were generated by mCPBA oxidation of corresponding Fe(III) porphyrins. The halogen substitution at the peripheral positions of the porphyrin leads to distortion of the planar porphyrin ring of |(TMP)Fe=O|+. The new species have beeen investigated by temperature-dependent EPR and field-dependent Mössbauer spectroscopy; for the evaluation of spectra, we adopted the spin-Hamiltonian formalism including exchange interaction explicitly. As in |(TMP)Fe=O|+, strong ferromagnetic spin coupling was observed with|J0|D=0.9-1 and a zero-field spltting of D∼32 cm-1. For consistent parametrization of EPR and Mössbauer results, anisotropic coupling had to be introduced. Compared to |(TMP)Fe=O|+ [1], analysis of the spectroscopic data shows that zero-field splitting and spin coupling is only slightly affected by the halogen distortion of the porphyrin structure.

Original languageEnglish
JournalHyperfine Interactions
Issue number1
Pages (from-to)803-808
Number of pages6
Publication statusPublished - 01.12.1994


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