Abstract
Magnetic susceptibility, 57Fe Mossbauer spectroscopy, and variable-temperature FTIR spectroscopy have been used to characterize the spin states of FeII(4,4′-dpb)2X2 (dpb = diphenyl-2,2′-bipyridyl; X = NCS-, NCSe-) in the temperature range 6 ≤ T ≤ 460 K. Both complexes show a continuous variation of the field-dependent effective magnetic moment over this range. Below ~ 325 K, both the infrared and Mossbauer spectroscopic signatures are insufficient to permit characterization of the spin state(s) of the metal atom in these complexes, but at higher temperatures, the FTIR data can be accounted for by the increasing population of a high (S = 2) spin state, while the Mössbauer spectra can be accounted for by a rapid (on the Mossbauer time scale) relaxation between two spin states. The existence of an intermediate (S = 1) spin state for Fe(II) is a consequence of a major distortion from octahedral symmetry of the metal-based orbitals, permitting a (near) degeneracy of the dz2 and dxy levels around this atom.
Original language | English |
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Pages (from-to) | 2535-2540 |
Number of pages | 6 |
Journal | Inorganic Chemistry |
Volume | 30 |
Issue number | 11 |
DOIs | |
State | Published - 1 May 1991 |