ISSN:
0947-6539
Keywords:
EPR spectroscopy
;
exchange coupling
;
iron
;
Moessbauer spectroscopy
;
O ligands
;
Chemistry
;
General Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
An asymmetric triangular FeIII complex has been synthesized by an unusual FeII-promoted activation of salicylaldoxime. Formation of the ligand 2-(bis(salicylideneamino)methyl)phenol in situ is believed to occur through the reductive deoximation of salicylaldoxime by ferrous ions. The trinuclear ferric complex has been characterized on the basis of elemental analysis, IR, variable-temperature magnetic susceptibility, and EPR and Mössbauer spectroscopies. The molecular structure established by X-ray diffraction consists of a trinuclear structure with a [Fe3(μ3-O)(μ2-OPh)]6+ core. Two iron ions are in a distorted octahedral environment having FeN2O4 coordination spheres, and the five-coordinated third iron ion, with an FeNO4 coordination sphere, is in a trigonal bipyramidal environment. The magnetic susceptibility measurements revealed an St = 5/2 ground state with the antiparallel exchange interactions J = - 34.3 cm-1, J' = - 4.7 cm-1, and D = - 0.90 cm-1. The EPR results are consistent with a ground state of S = 5/2 together with a negative D5/2 value. The Mössbauer isomer shifts together with the quadrupole splitting also provide evidence for the high-spin state of the three ferric sites. Magnetic Mössbauer spectra lead to the conclusion that the internal magnetic fields possibly lie in the plane of the three ferric ions.
Additional Material:
6 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/chem.19970030205
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