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Reacciones de inserción de acrilonitrilo de los complejos alquilo de paladio catiónico

Fan Wu¹, Stephen R Foley, Christopher T Burns

¹Department of Chemistry, The University of Chicago, 5735 South Ellis Avenue, Chicago, IL 60637, USA.

Journal of the American Chemical Society

|February 11, 2005

Resumen

Los catalizadores de paládio con acrilonitrilo (AN) forman aductos ligados a N que insertan AN, lo que lleva a especies agregadas. La agregación y la baja reactividad de inserción impiden la polimerización de AN con estos catalizadores.

Área de la Ciencia:

Química organometálica Química orgánica de los metales.
La catálisis es la catálisis.
La polimerización por polimerización

Sus antecedentes:

Investigación de reacciones catalizadas por el paladio que involucran acrilonitrilo (AN).
Exploración de varios andamios de ligandos (L(2) para complejos de paladio.

Objetivo del estudio:

Comprender la reactividad de las especies L(2)PdMe+ con el acrilonitrilo.
Para identificar los obstáculos a la inserción de acrilonitrilo polimerización y copolimerización.

Principales métodos:

Síntesis y caracterización de los adductos de paladio-AN utilizando espectroscopia de RMN, ESI-MS y IR.
Investigación de las reacciones de inserción y posterior caracterización del producto.
Estudios comparativos con coordinación e inserción de etileno.

Principales resultados:

Formación de añadidos de acrilonitrilo unidos al N (L(2) Pd(Me) ((NCCH=CH(2)) +) a partir de los precursores del paladio.
2,1-inserción de AN en la mayoría de los aductos (3a-e) dando L(2) Pd{CH(CN) Et}+, que se agregan en [L(2) Pd{CH(CN) Et}]{n) n) +.
La inserción de acrilonitrilo es más lenta que la inserción de etileno, y la agregación compite con la coordinación del monómero.

Conclusiones:

La agregación de especies de alquilo de paladio es una barrera significativa para la polimerización de inserción de acrilonitrilo.
La baja reactividad de inserción de los complejos de substrato de alquilo-paladio impide aún más la polimerización.
2) Los catalizadores PdR+ se enfrentan a desafíos para una polimerización o copolimización efectiva de AN.

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