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Iridio de cuatro coordenadas ((I) monohidruro: unión reversible al dinitrógeno, activaciones de enlaces y

Matthew D Millard¹, Curtis E Moore, Arnold L Rheingold

¹Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, Mail Code 0358, La Jolla, California 92093-0358, USA.

Journal of the American Chemical Society

|June 17, 2010

Resumen

Este estudio aisló y caracterizó con éxito complejos de monohidruro de iridio ((I) monohidruro de cuatro coordenadas usando un ligando de fosfina estéricamente impedido. Estos hallazgos proporcionan evidencia concreta de especies reactivas previamente postuladas en las transformaciones químicas.

Área de la Ciencia:

Química organometálica Química orgánica de los metales.
Coordinación Química de la Coordinación
Investigación de la investigación de la catálisis.

Sus antecedentes:

Se propone que los complejos de iridio ((I) monohidruro de cuatro coordenadas sean reactivos intermedios en varias reacciones químicas.
Los intentos anteriores de aislar estas especies se han visto obstaculizados por su inherente inestabilidad.
El desarrollo de ligandos robustos es crucial para estabilizar las especies organometálicas transitorias.

Objetivo del estudio:

Para sintetizar y caracterizar los complejos de monohidruro de iridio (((I) de cuatro coordenadas aislables.
Para proporcionar pruebas definitivas de la existencia de estas especies escurridizas.
Para explorar la reactividad y estabilidad de estos complejos utilizando un ligando de fosfina estéricamente obstaculizado.

Principales métodos:

Síntesis de complejos de iridio utilizando un ligando de fosfina sustituido por metilenoadamantilo (L(mAd)).
Reacciones de los precursores de cloruro de dihidruro con reactivos organometálicos (PhMgBr, Li[HBEt(3) ]).
Caracterización espectroscópica (NMR) y estudios de reactividad bajo diversas condiciones (N(2), H(2), H(2) O, Li[12-c-4]).

Principales resultados:

Aislamiento de un cuadrado plano de iridio ((I) complejo monohidruro, HIr ((N ((2)) ((L ((mAd)) ((2), y un complejo trihidruro, H ((3) Ir (((L ((mAd)) ((2).
Observación de un equilibrio entre HIr (N2) y su forma ciclometalizada, HIr (kappa) -P,C-L (mAd) y L (mAd).
Generación de complejos pentahidruro y dihidruro hidróxido por reacción con H(2) y H(2) O, respectivamente.
Formación de una sal monohidrida de cuatro coordenadas estables Ir (I), [Li (C) -4) ], [Li (C) -2) ], [HIr (kappa) -2) -P, C (L) -mAd (L) -mAd ()) ] .

Conclusiones:

El uso del ligando L ((mAd) estéricamente inhibido permitió el aislamiento de complejos monohidruro de iridio ((I) de cuatro coordenadas, previamente escurridizos.
Estos complejos exhiben una reactividad única, formando varias especies de hidrido bajo diferentes condiciones de reacción.
El estudio proporciona una plataforma estable para investigar la química fundamental de estos importantes intermediarios organometálicos.

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