Abstract
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.
Originalsprache | Englisch |
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Zeitschrift | Hyperfine Interactions |
Jahrgang | 91 |
Ausgabenummer | 1 |
Seiten (von - bis) | 803-808 |
Seitenumfang | 6 |
ISSN | 0304-3834 |
DOIs | |
Publikationsstatus | Veröffentlicht - 01.12.1994 |