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Reacciones de abstracción de beta-hidruro mediadas por el ácido de Lewis de la divalente M ((C ((SiHMe ((2)) ((3)))
KaKing Yan1, Brianna M Upton, Arkady Ellern
1Department of Chemistry and U.S. Department of Energy Ames Laboratory, Iowa State University, Ames, Iowa 50011-3111, USA.
Journal of the American Chemical Society
|October 3, 2009
Resumen
Los compuestos de calcio e iterbio con grupos beta-agóticos de SiH muestran reacciones de abstracción de hidruro con ácidos de Lewis, formando productos inesperados y descartando las vías de eliminación beta en la química organometálica.
Área de la Ciencia:
- Química organometálica Química orgánica de los metales.
- Química del silicio Química del silicio
- Coordinación Química de la Coordinación
Sus antecedentes:
- Se sintetizaron compuestos divalentes de calcio e iterbio con grupos beta-agóticos de SiH.
- Estos compuestos poseen enlaces SiH con un carácter hidrídico significativo.
- Estudios previos sugirieron posibles vías de eliminación de beta en sistemas relacionados.
Objetivo del estudio:
- Para investigar la reactividad de los compuestos M{C}{SiHMe}{2}{3}{2}{THF}{2} con ácidos de Lewis.
- Para dilucidar los mecanismos de reacción, explorando específicamente la eliminación beta frente a la abstracción de hidruro.
- Para caracterizar los productos formados a partir de la reacción con ácidos de Lewis a base de boro.
Principales métodos:
- Síntesis y caracterización de complejos divalentes de calcio e iterbio.
- Análisis espectroscópico (por ejemplo, RMN) y cristalografía de rayos X para determinar las características estructurales.
- Reacciones con los ácidos de Lewis, específicamente B ((C ((6) F ((5)) ((3)) y BPh ((3), seguidas por el aislamiento y análisis del producto.
Principales resultados:
- Los compuestos M{C}{SiHMe}{2}{3}{2}THF{2} exhiben grupos beta-agóticos de SiH.
- Las reacciones con los ácidos de Lewis B ((C ((6) F ((5)) ((3)) y BPh ((3)) dan como resultado predominantemente la abstracción de hidruro, formando [HB ((C ((6) F ((5)) ((3)) ] o aniones relacionados.
- Se observó la formación de 1,3-disilaciclobutano, pero se descartó que fuera un producto de la eliminación beta basado en estequiometría y otros productos.
Conclusiones:
- La eliminación beta no es una vía de reacción viable para estos compuestos específicos M(C(SiHMe(2)) ((3)) ((2)) THF(2), a pesar de la presencia de grupos hidruro SiH y centros metálicos ácidos de Lewis.
- La abstracción de hidruro es la vía de reacción dominante cuando estos compuestos interactúan con los ácidos de Lewis.
- El estudio aclara el panorama de reactividad de los complejos metálicos de baja coordinación con enlaces de silicio-hidruro.
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