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La escisión de enlaces N-N en los diazoalcanos por un complejo de hierro bis(imino) piridina-piridina
Sarah K Russell1, Emil Lobkovsky, Paul J Chirik
1Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853, USA.
Journal of the American Chemical Society
|January 9, 2009
Resumen
Los complejos de dinitrógeno de hierro reaccionan con los diazoalcanes para romper el enlace N-N, formando complejos de nitrilo de hierro e imina. Esta reacción se produce a través de un intermediario de hierro alquilideno y una vía de cicloadición [4pi + 2pi].
Área de la Ciencia:
- Química organometálica Química orgánica de los metales.
- Coordinación Química de la Coordinación
- Investigación de fijación de nitrógeno Investigación de fijación de nitrógeno
Sus antecedentes:
- Los ligandos de bis (imino) piridina son cruciales para estabilizar los complejos reactivos de hierro.
- Los complejos de hierro se investigan como alternativas a los metales preciosos en la catálisis.
- La reactividad del dinitrógeno coordinado (N2) es clave para la fijación del nitrógeno.
Objetivo del estudio:
- Para investigar la reacción de un complejo de dinitrógeno de hierro bis(imino) piridina con diazoalcanos monosubstituidos.
- Para dilucidar el mecanismo de la escisión de enlaces N-N en el complejo de dinitrógeno de hierro.
- Explorar la utilidad sintética de esta reacción para generar nuevos complejos de hierro.
Principales métodos:
- Reacción de ((iPr) PDI) Fe ((N2) 2) con varios diazoalcanos monosubstituidos (N2CHR).
- Análisis espectroscópico (AMN) en benceno-d6 a 23°C.
- Estudios mecánicos que incluyen análisis cinético y atrapamiento intermedio (implicado).
Principales resultados:
- La escisión rápida del enlace N-N se produjo con la adición de diazoalcanes.
- Formación de complejos de nitrilo de hierro (((iPr) PDI) FeNCR) y imina (((iPr) PDI) FeHNCHR).
- Las azinas de arilo también fueron escindidas, dando los mismos productos.
- Los estudios mecánicos indicaron una vía que involucra un alquilideno de hierro y [4pi + 2pi] cicloadición.
Conclusiones:
- Los diazoalcanos monosubstituidos efectivamente cortan el enlace N-N del complejo de dinitrógeno de hierro.
- La reacción procede a través de un mecanismo complejo que involucra cicloadición y migración de hidrógeno.
- Esto proporciona una ruta sintética a los complejos de nitrilo de hierro e imina a partir de un precursor de dinitrógeno.
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