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Sobre la reactividad de los complejos de hierro mononuclear (V) oxo
Soumen Kundu1, Jasper Van Kirk Thompson, Alexander D Ryabov
1Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, USA.
Journal of the American Chemical Society
|October 12, 2011
Resumen
Los catalizadores de ligando macrocíclico tetraamido férrico (TAML) forman especies Fe (V) oxo que se componen de dímeros Fe (IV). Los efectos estéricos y la electrónica del sustrato gobiernan la dinámica de la oxidación del sulfuro, revelando las TAML como imitadores efectivos de la peroxidasa.
Área de la Ciencia:
- La catálisis de la catálisis.
- Química organometálica Química orgánica de los metales.
- Reacciones de oxidación Reacciones de oxidación.
Sus antecedentes:
- Los complejos de hierro del ligando tetraamido macrocíclico (TAML) son catalizadores de oxidación conocidos.
- Las enzimas peroxidasa utilizan especies de oxóferos de hierro de alta valencia para la oxidación del sustrato.
Objetivo del estudio:
- Para investigar el mecanismo de oxidación de los catalizadores TAML férricos por el ácido m-cloroperoxibenzoico.
- Para caracterizar las especies de hierro de alta valencia formadas y su reactividad.
- Para dilucidar los factores que controlan la oxidación de sulfuro por estos catalizadores.
Principales métodos:
- Oxidación de complejos Fe(III) TAML con ácido m-cloroperoxibenzoico a bajas temperaturas.
- Caracterización espectroscópica de los intermediarios de dímeros Fe(V) oxo y Fe(IV).
- Estudios cinéticos de la oxidación del sulfuro con diferentes componentes electrónicos del sustrato y el volumen estérico TAML.
Principales resultados:
- Se formaron y caracterizaron complejos Fe(V) oxo TAML.
- Las especies Fe(V) oxo se componen con Fe(III) TAML para obtener Fe(IV) dimeros.
- La cinética de la oxidación del sulfuro fue influenciada tanto por la electrónica del sustrato como por el obstáculo estérico TAML.
- Las especies Fe (((V) exhibieron una reactividad significativamente mayor hacia los sulfuros que las especies Fe (((IV).
Conclusiones:
- Los catalizadores TAML pueden generar especies reactivas de Fe (V), imitando la actividad de la peroxidasa.
- Los factores estéricos y electrónicos juegan un papel crucial en la modulación del ciclo catalítico.
- La brecha de reactividad entre las especies Fe ((V) y Fe ((IV) de TAML destaca su potencial en reacciones de oxidación selectiva.
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