Spin-state-dependent oxygen sensitivity of iron dithiolates: sulfur oxygenation or disulfide formation.
J Biol Inorg Chem
; 13(8): 1219-30, 2008 Nov.
Article
en En
| MEDLINE
| ID: mdl-18633652
The oxygen sensitivity of two related iron(III) dithiolate complexes of the ligand [4,7-bis-(2'-methyl-2'-mercatopropyl)-1-thia-4,7-diazacyclononane], (bmmp-TASN)FeCN (1) and (bmmp-TASN)FeCl (2), has been examined. Oxygen exposure of the low-spin complex 1 yields the disulfonate complex (bmmp-O6-TASN)FeCN (3) as an olive-green solid with characteristic peaks in the IR spectrum at 1262, 1221, 1111, 1021, 947, 800, and 477 cm(-1). The corresponding nickel dithiolate, (bmmp-TASN)Ni (4), yields the related disulfonato derivative, (bmmp-O6-TASN)Ni (5) upon addition of H2O2 (IR bands at 1258, 1143, 1106, 1012, 800, and 694 cm(-1). Oxygen exposure of the high-spin complex 2 results in disulfide formation and decomplexation of the metal with subsequent iron-oxo cluster formation. Complexes 1 and 2 were examined using density functional theory calculations. A natural bond order/natural localized molecular orbital covalency analysis reveals that the low-spin complex 1 contains Fe-Sthiolate bonds with calculated covalencies of 75 and 86%, while the high-spin complex 2 contains Fe-Sthiolate bonds with calculated covalencies of 11 and 40%. The results indicate the degree of covalency of the Fe-S bonds plays a major role in determining the reaction pathway associated with oxygen exposure of iron thiolates. The X-ray structures of 1, 4, and 5 are reported.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Oxígeno
/
Compuestos de Sulfhidrilo
/
Azufre
/
Detección de Spin
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Disulfuros
/
Hierro
Tipo de estudio:
Diagnostic_studies
/
Prognostic_studies
Idioma:
En
Revista:
J Biol Inorg Chem
Asunto de la revista:
BIOQUIMICA
Año:
2008
Tipo del documento:
Article
País de afiliación:
Estados Unidos
Pais de publicación:
Alemania