Evidence for intermediate (S = 1) spin state stabilization in bis(4,4'-diphenyl-2,2'-bipyridyl)bis(isothiocyanato)iron and bis(4,4'-diphenyl-2,2'-bipyridyl)bis(isoselenocyanato)iron from susceptibility, infrared, and iron-57 Moessbauer data

Autor:	I. Felner, R. H. Herber, D. C. Figg
Rok vydání:	1991
Předmět:	education.field_of_study Spin states Magnetic moment Octahedral symmetry Chemistry Relaxation (NMR) Population Infrared spectroscopy Magnetic susceptibility Inorganic Chemistry Crystallography Nuclear magnetic resonance Mössbauer spectroscopy Physical and Theoretical Chemistry education
Zdroj:	Inorganic Chemistry. 30:2535-2540
ISSN:	1520-510X 0020-1669
DOI:	10.1021/ic00011a015
Popis:	Magnetic susceptibility, {sup 57}Fe Mossbauer spectroscopy, and variable-temperature FTIR spectroscopy have been used to chracterize the spin states of Fe{sup 11} (4,4{prime}-dpb){sub 2}X{sub 2} (dpb = diphenyl-2,2{prime}-bipyridyl; X = NCS{sup {minus}}, NCSe{sup {minus}}) in the temperature range 6 {le} T {le} 460 K. Both complexes show a continuous variation of the field-dependent effective magnetic moment over this range. Below {approximately}325 K, both the infrared and Mossbauer spectroscopic signatures are insuffiecient to permit characterization ofthe spin state(s) of the metal atom in these complezes, but at higher temperatures, the FTIR data can be accounted for by the increasing population of a high (S = 2) spin state, while the Mossbauer 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) in a consequence of a major distortion from octahedral symmetry of the metal-based orbitals, permitting a (near) degeneracy of the d{sub x}2 and d{sub xy} levels around this atom.
Databáze:	OpenAIRE
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