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Complejos de dos coordenadas d9. complejos de dos coordenadas d9. síntesis y oxidación de NHC níquel (I) amidas
Carl A Laskowski1, Gregory L Hillhouse
1Gordon Center for Integrative Science, Department of Chemistry, The University of Chicago, Chicago, Illinois 60637, USA.
Journal of the American Chemical Society
|September 27, 2008
Resumen
Se sintetizaron nuevos complejos de níquel ((I) con ligandos voluminosos. Estos complejos se someten a reacciones de oxidación y reordenamiento, produciendo estructuras únicas de iminosilano y níquel dimérico, expandiendo la química del organonickel.
Área de la Ciencia:
- Química organometálica Química orgánica de los metales.
- Catálisis de níquel y níquel.
- Coordinación Química de la Coordinación
Sus antecedentes:
- Los complejos de níquel de baja coordinación son intermediarios cruciales en la catálisis.
- Comprender su reactividad proporciona información sobre los ciclos catalíticos.
- Los ligandos estéricamente exigentes influyen en la estabilidad y la reactividad del complejo de níquel.
Objetivo del estudio:
- Para sintetizar y caracterizar nuevos complejos monoméricos de 2 coordenadas Ni (I).
- Investigar la reactividad de estos complejos de Ni (I) durante la oxidación.
- Para explorar la formación de estructuras inusuales que contienen níquel.
Principales métodos:
- Síntesis de complejos de níquel (I) a partir de un dímero de cloruro de níquel (I) y ligandos voluminosos de amida/anilido.
- Oxidación electroquímica de los complejos de níquel sintetizados.
- Caracterización de productos utilizando técnicas espectroscópicas y cristalografía de rayos X (implicado).
Principales resultados:
- Síntesis exitosa de complejos monoméricos de Ni (I) de 2 coordenadas: (IPr) Ni (N (SiMe3) 2) y (IPr) Ni (NHAr) (3).
- La oxidación del complejo 2 condujo a la eliminación de beta-Me, formando un complejo de iminosilano estabilizado en base [(IPr) Ni(CH3) {kappa1-N(SiMe3) = SiMe2.Et2O}][BArF4] (6).
- La oxidación del complejo 3 produjo un complejo cationico eta3-coordinado (4) que se reorganizó en una estructura dimérica (5) tras la pérdida de THF.
Conclusiones:
- Demostró la accesibilidad de nuevos complejos de 2 coordenadas Ni (I) con ligandos voluminosos de carbenos N-heterocíclicos (IPr).
- Reveló vías únicas de reactividad que incluyen la eliminación de beta-Me y la reorganización de ligandos en la oxidación de un electrón.
- Amplió el alcance de la química del níquel orgánico al formar especies de níquel iminosilano y dimérico sin precedentes.
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