Low-Coordinate Iron Chalcogenolates and Their Complexes with Diethyl Ether and Ammonia.
Inorg Chem
; 60(9): 6712-6720, 2021 May 03.
Article
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| MEDLINE
| ID: mdl-33848423
ABSTRACT
Treatment of Fe{N(SiMe3)2}2 with 2 equiv of the appropriate phenol or thiol affords the dimers {Fe(OC6H2-2,6-But2-4-Me)2}2 (1) and {Fe(OC6H3-2,6-But2)2}2 (2) or the monomeric Fe{SC6H3-2,6-(C6H3-2,6-Pri2)2}2 (3) in moderate to excellent yields. Recrystallization of 1 and 2 from diethyl ether gives the corresponding three-coordinate ether complexes Fe(OC6H3-2,6-But2-4-Me)2(OEt2) (4) and Fe(OC6H3-2,6-But2)2(OEt2) (5). In contrast, no diethyl ether complex is formed by the dithiolate 3. The 1H NMR spectra of 4 and 5 show equilibria between the ether complexes and the base-free dimers. A comparison of these spectra with those of the dimeric 1 and 2 allows an unambiguous assignment of the paramagnetically shifted signals. Treatment of 1 with excess ammonia gives the tetrahedral diammine Fe(OC6H2-2,6-But2-4-Me)2(NH3)2 (6). Ammonia is strongly coordinated in 6, with no apparent loss of ammine ligand either in solution or upon heating under low pressure. In contrast, significantly weaker ammonia coordination is observed when dithiolate 3 is treated with excess ammonia, which gives the diammine Fe{SC6H3-2,6-(2,6-Pri2-C6H3)2}2(NH3)2 (7). Complex 7 readily loses ammonia either in solution or under reduced pressure to give the monoammine complex Fe{SC6H3-2,6-(2,6-Pri2-C6H3)2}2(NH3) (8). The weak binding of ammonia by iron thiolate 7 reflects the likely behavior of the proposed iron-sulfur active site in nitrogenases, where release of ammonia is required to close the catalytic cycle.
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1
Bases de datos:
MEDLINE
Asunto principal:
Calcógenos
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Éteres
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Complejos de Coordinación
/
Amoníaco
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Hierro
Idioma:
En
Revista:
Inorg Chem
Año:
2021
Tipo del documento:
Article
País de afiliación:
Estados Unidos