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La formación de oxohierro (IV) desencadenada por Sc3+ a partir de O2 y su precursor de hierro no hemo (II) a través
Feifei Li1, Katherine M Van Heuvelen, Katlyn K Meier
1Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, Minnesota 55455, United States.
Journal of the American Chemical Society
|June 28, 2013
Resumen
El escandio redóxido-inactivo (III) activa el oxígeno en los centros de hierro, formando un complejo de oxohierro (IV). Un escandio (III) peroxohierro (III) intermedio facilita la escisión de enlaces O-O, crucial para la catálisis del hierro no hemo.
Área de la Ciencia:
- Química bioorgánica Química bioorgánica.
- Química organometálica Química orgánica de los metales.
- La catálisis de la catálisis.
Sus antecedentes:
- Las enzimas de hierro no hemo juegan un papel vital en las reacciones de oxidación biológica.
- Comprender los mecanismos de activación de O2 es clave para desarrollar catalizadores sintéticos.
- Se sabe que los ácidos de Lewis influyen en la reactividad centrada en el metal.
Objetivo del estudio:
- Para investigar el papel de un ácido de Lewis, Sc(3+), en la activación de O2 por un complejo Fe(II).
- Para modelar y caracterizar los potenciales intermediarios en la vía de activación de O2.
- Para dilucidar el mecanismo de la escisión de enlaces O-O facilitado por Sc(3+).
Principales métodos:
- Utilizado Fe (II) (tetrametilciclam) [Fe (II) (TMC) ] como el complejo de hierro.
- Empleado Sc(3+) como un ácido de Lewis para desencadenar la activación de O2.
- Se ha generado y caracterizado un adducto Sc(3+) de [Fe(III)(η(2)-O2)(TMC)](+) utilizando rutas alternativas.
- Investigó la conversión del peroxo intermedio en un complejo de oxoirón (IV).
Principales resultados:
- Redox-inactivo Sc(3+) desencadenó con éxito la activación de O2 por Fe(II)(TMC).
- Se generó un adducto Sc(3+) sin precedentes de [Fe ((III) ((η(2) -O2) ((TMC) ](+) con un núcleo Fe ((3+) - ((μ-η(2):η(2) -peroxo) -Sc(3+) sin precedentes.
- Se demostró que este peroxo intermedio se convierte en el complejo de oxoirón (IV).
- La presencia de BPh4(-) facilitó la reacción como donante de electrones.
Conclusiones:
- Sc(3+) actúa como un ácido de Lewis para promover la activación de O2 y la escisión de enlaces O-O en los centros de hierro no hemo.
- El caracterizado complejo Sc(3+) peroxoirón(III) sirve como un intermediario viable en este proceso.
- Estos hallazgos ofrecen información sobre los mecanismos catalíticos de la activación del oxígeno relevantes para la química bioinorgánica.
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