Valence trapping of mixed-valence (Fe sub 3 O(O sub 2 CCH sub 3 ) sub 6 (py) sub 3 )ter dot S (S = solvent) complexes at high pressure

Journal Article · Wed May 01 04:00:00 EDT 1991 · Inorganic Chemistry; (United States)

DOI:https://doi.org/10.1021/ic00009a009· OSTI ID:5942516

McCusker, J K ^[1]; Jang, H G; Zvagulis, M; Ley, W; Drickamer, H G ^[2]; Hendrickson, D N ^[3]

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1. Univ. of Illinois, Urbana (United States) Univ. of California, San Diego, La Jolla (United States)
2. Univ. of Illinois, Urbana (United States)
3. Univ. of California, San Diego (United States)

The transformation from valence detrapped to valence trapped for two oxo-centered trinuclear iron acetate complexes is studied at pressures up to 95 kbar with the use of a diamond anvil cell. Variable-pressure {sup 57}Fe Mossbauer spectra are presented for {sup 57}Fe-enriched (Fe{sub 3}O(O{sub 2}CCH{sub 3}){sub 6}(py){sub 3}){times}py (1) and (Fe{sub 3}O(O{sub 2}CCH{sub 3}){sub 6}(py){sub 3}){times}CHCl{sub 3} (2), where py is pyridine. At 298 K and applied pressures less than {approximately}20 kbar, each of the complexes gives a spectrum with a single quadrupole-split doublet, which indicates that complexes 1 and 2 are interconverting faster than the Mossbauer time scale under these conditions. Application of pressure in excess of {approximately}80 kbar leads to both complexes becoming valence trapped, as indicated by two doublets in the Mossbauer spectrum with an area ratio of {approximately}2:1 (Fe{sup III}:Fe{sup II}). At intermediate pressures, each of these complexes gives a Mossbauer spectrum that can be fit as a superposition of a valence detrapped doublet and a valence trapped four-line pattern. The nature of the pressure-induced transformations observed in complexes 1 and 2 is discussed with reference to the phase diagram derived from a spin-Hamiltonian theoretical approach that parameterizes intermolecular interactions in terms of the molecular field approximation. 11 refs., 4 figs., 2 tabs.

• DOE Contract Number: AC02-76ER01198
• OSTI ID: 5942516
• Journal Information: Inorganic Chemistry; (United States), Journal Name: Inorganic Chemistry; (United States) Vol. 30:9; ISSN 0020-1669; ISSN INOCA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
400202 -- Isotope Effects
Isotope Exchange
& Isotope Separation
ALKANES
AZINES
COMPLEXES
DATA
EVEN-ODD NUCLEI
EXPERIMENTAL DATA
HETEROCYCLIC COMPOUNDS
HYDROCARBONS
INFORMATION
INTERMEDIATE MASS NUCLEI
IRON 57
IRON COMPLEXES
IRON ISOTOPES
ISOTOPES
MOESSBAUER EFFECT
MOLECULAR STRUCTURE
NUCLEI
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OXYGEN COMPOUNDS
PRESSURE EFFECTS
PYRIDINES
STABLE ISOTOPES
TRANSITION ELEMENT COMPLEXES