To a solution of (Ia) in CH2Cl2 was added phenoxathiinium hexachloroantimonate, the resulting oxidation product, the complex (IIa), was shown to be an iron(III) porphyrin π‐cation radical rather than an iron(IV) compound.

IIIS, bond distances; Table IVS, bond angles; listings of magnetic susceptibility data for [Cu(TMP')][SbCl6]-C6H5F and [VO-(TPP')] [SbCl6] (9 pages); listings (X10) of the observed and calculated structure amplitudes of [Cu(TPP')][SbCl6] (13 pages). Ordering information is given on any current masthead page.

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Articles you may be interested inStudy of the electronic states of the allyl radical using spin-coupled valence bond theory Susceptibility and Mössbauer study of coupled admixedspin state in [Fe(OEP) (3ClPy)]+ dimers J. Chem. Phys. 85, 5212 (1986); 10.1063/1.451686 Mössbauer and susceptibility study of interheme spin coupling in [Fe (OEP) (2MeHIm)]+ dimers J. Chem. Phys. 83, 5945 (1985); 10.1063/1.449626Mössbauer studies of lowsymmetry crystal fields in lowspin ferric heme complexesThe ferric metalloporphyrin1T-radical cation complexes Fe (III) (OCI0 3 lz (TPP') and [Fe(1I1) CI (TP~')] [SbC1 6 ] were examined in microcrystalline form by MOssbauer spectroscopy and magnetIc susceptometry over a range of temperatures and applied fields. All measurements on the six-coordinate Fe(OCI0 3 lz (TPP' ) were consistent with isolated molecules having an S = 5/2 iron site with zero field splitting (12 cm -I) S: that is ferromagnetically coupled to the S = 1/2 porphyrin radical by an energy term ( -110 cm -I) SOS. Thus the ground state is overall spin-3.In the five-coordinate [FeCI (TPP' )] [SbC~] the susceptibility is in reasonable agreement with the results of a calculation based on zero field splitting (12 cm -I) S: for the S = 5/2 iron and antiferromagnetic coupling (200 cm -I) SOS with the radical to give an overall spin-2 ground state.However, the MOssbauer measurements require a more complicated model having the same large intramolecular iron-radical coupling, a smaller zero field splitting (3 cm -I) S:, and weak intermolecular antiferromagnetic coupling between heme pairs given by (32 cm -I) S os or . al 1 1 1 2 , eqwv ent y, (0.65 cm-) SI"S2' A slightly improved correspondence with the measured susceptibility results. The intermolecular antiferromagnetic coupling probably results from crystallization of the [FeCI (TPP' )] + cations in face-to-face dimers as observed in other closely related five-coordinate iron (III) porphyrins.

048ChemInform Abstract The magnetic interactions between metal and ligand spins in metalloporphyrin π-cation radicals (I) are investigated as a function of d orbital type for synthetically accessible compounds containing S = 1/2 metals from the first transition series. The preparation of (Ia)-(Id) from the corresponding neutral complex by oxidation with phenoxathiinylium hexachloroantimonate is described. Extensive studies are carried out on the presumably planar compound (Ib) with an overall S = 1 state. The ferromagnetic coupling of spins is rationalized as arising from the exchange interaction of unpaired electrons in orthogonal magnetic orbitals. By contrast, (Ia), crystallizing in the space group P1 with Z=2, has a ruffled porphyrin core in the solid state and is diamagnetic (S = 0). The antiferromagnetic coupling is rationalized in terms of overlap of the magnetic orbitals, i.e. bond formation with spin pairing in the bonding MO. Applications to analogous systems of other metals are discussed.