100333-81-1Relevant articles and documents
[Fe(OEP?)(X)]+ π-Cation Radicals: Characterization and Spin-Spin Interactions
Schulz, Charles E.,Song, Hungsun,Mislankar, Anil,Orosz, Robert D.,Reed, Christopher A.,Debrunner, Peter G.,Robert Scheldt
, p. 406 - 412 (1997)
The preparation and characterization of the π-cation radical derivatives of [Fe(OEP)(X)] (X = Cl , Br-) is reported. Three different derivatives have been prepared: [Fe(OEP?)(Cl)]ClO4, [Fe(OEP?)(Cl)][SbCl6], and [Fe(OEP?)(Br)][SbCl6]. All derivatives have been characterized by UV - vis, IR, and Mo?ssbauer spectroscopy. In addition. [Fe(OEP?)(Cl)]ClO4 has been characterized by a single-crystal structure determination, and [Fe(OEP?)(Cl)][SbCl6] and [Fe(OEP)(Br)][SbCl6] have been studied by temperature-dependent magnetic susceptibility measurements and Mo?ssbauer measurements in an applied magnetic field. The X-ray structure of [Fe(OEP?)(Cl)]ClO4 reveals a five-coordinate porphyrinate species that forms tight cofacial π-π dimers in which the two porphyrin rings are almost exactly overlapped with an inter-ring separation of 3.24 A?, a lateral shift of 0.2 A?, and a twist angle between the two rings of 31.2°; the two iron atoms are 4.112 A? apart. Crystal data: C37H46FeCl4O4N4,a = 27.454(7) A?, b = 15.322(3) A?, c = 19.802(3) A?, β= 116.14 (2)°, monoclinic, C2/c, Z = 8. Iron(III) is found to be in the high-spin state in all derivatives. The magnetic data (susceptibility and Mo?ssbauer) have been interpreted in terms of two spin coupling models. Both models give a picture of strong coupling between the various spins in the dimeric species. In the model judged to best fit all data with a physically meaningful zero-field splitting, there are three terms in the total Hamiltonian: an axial zero-field splitting parameter D for the high-spin iron, an intramolecular antiferromagnetic coupling -2JFe-r(S · s) between the iron spin S = 5/2 and the π-cation radical s = 1/2 spin, and an intermolecular antiferromagnetic coupling -2JR-R(S + s)· (S′ +-s)-(5′ +s′) between the total spins on each half of the dimer.
