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Síntesis de complejos NHC por adición oxidativa de 2-cloro-N-metilbenzimidazol

Tim Kösterke¹, Tania Pape, F Ekkehardt Hahn

¹Institut für Anorganische und Analytische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstrasse 30, D-48149 Münster, Germany.

Journal of the American Chemical Society

|January 29, 2011

Resumen

Los investigadores sintetizaron ligandos de carbenos N-heterocíclicos (NHC) a través de la adición oxidativa de un derivado de benzimidazol a los complejos de paladio y platino. Esta reacción produjo compuestos específicos de NHC de paladio y platino.

Área de la Ciencia:

Química organometálica Química orgánica de los metales.
Coordinación Química de la Coordinación
La catálisis de la catálisis.

Sus antecedentes:

Los carbenos N-heterocíclicos (NHC) son ligandos versátiles en la química organometálica, conocidos por sus fuertes propiedades de donación de sigma.
Los complejos de paladio y platino son ampliamente estudiados por sus aplicaciones catalíticas y su reactividad única.
La síntesis de nuevos ligandos NHC a menudo implica la funcionalización de precursores heterocíclicos.

Objetivo del estudio:

Para investigar la adición oxidativa de 2-cloro-N-metilbenzimidazol a los complejos de paladio y platino.
Para sintetizar y caracterizar nuevos ligandos NHC sustituidos por NH,NMe.
Para explorar los resultados estereoquímicos de estas reacciones con diferentes centros metálicos.

Principales métodos:

La reacción involucró la adición oxidativa de 2-cloro-N-metilbenzimidazol a los complejos tetrácicos (trifenilfosfina) de paladio (palladio) y tetrácicos (trifenilfosfina) de platino (platino).
Posterior N-protonación de las especies intermedias.
Caracterización de los productos resultantes utilizando técnicas espectroscópicas y cristalografía de rayos X (implicado).

Principales resultados:

Para el paladio, la reacción produjo el complejo trans-[3]BF(4) exclusivamente.
Para el platino, la reacción produjo una mezcla de cis-[4]BF(4) (producto principal) y trans-[4]BF(4) (producto secundario).
El estudio demuestra la reactividad diferencial y la estereoselectividad basada en el centro metálico (Pd vs. Pt).

Conclusiones:

La adición oxidativa de 2-cloro-N-metilbenzimidazol proporciona una ruta viable hacia los ligandos NHC sustituidos por NH,NMe.
La elección del metal (paladio o platino) influye significativamente en el resultado estereoquímico de la reacción.
Estos hallazgos contribuyen al desarrollo de nuevas metodologías sintéticas para los ligandos NHC y sus complejos metálicos.

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