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La descomposición de los catalizadores de metátesis de olefinas de rutenio en los catalizadores de metátesis de
Soon Hyeok Hong1, Anna G Wenzel, Tina T Salguero
1Arnold and Mabel Beckman Laboratory of Chemical Synthesis, Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA.
Journal of the American Chemical Society
|June 6, 2007
Resumen
Los catalizadores de la metátesis de rutenio que contienen fosfinas se descomponen a través de sales de metilfosfonio, lo que sugiere un ataque nucleófilo. Los catalizadores libres de fosfina producen especies no identificadas de hidruro de rutenio durante la descomposición.
Área de la Ciencia:
- Química organometálica Química orgánica de los metales.
- La catálisis de la catálisis.
- Mecanismos de reacción Mecanismos de reacción
Sus antecedentes:
- Los catalizadores de rutenio son vitales en la metátesis de las olefinas.
- Comprender las vías de descomposición del catalizador es crucial para optimizar su aplicación y estabilidad.
- Los complejos de metilideno sirven como modelos valiosos para estudiar el comportamiento del catalizador de rutenio.
Objetivo del estudio:
- Para investigar los mecanismos de descomposición de los catalizadores de metátesis de rutenio utilizando complejos de metilideno.
- Para aclarar el papel de los ligandos de fosfina en la descomposición del catalizador.
- Para caracterizar los productos de descomposición de los catalizadores que contienen fosfina y los que no la contienen.
Principales métodos:
- Síntesis y caracterización de complejos de rutenio metilideno.
- Estudios cinéticos de las reacciones de descomposición de catalizadores.
- Análisis de los productos de descomposición mediante técnicas espectroscópicas.
- Investigación de la descomposición en presencia de sustratos modelo de olefinas como el etileno.
Principales resultados:
- Los complejos de metilideno que contienen fosfina se descomponen para formar sales de metilfosfonio a través de la cinética de primer orden.
- La vía de descomposición para los complejos que contienen fosfina probablemente implica un ataque nucleofílico por la fosfina disociada en el carbono de metilideno.
- Descomposición de un catalizador libre de fosfina en presencia de especies no identificadas de hidruro de rutenio generadas por etileno.
- Se sintetizó y caracterizó un nuevo complejo de rutenio, (H2IMes) ((pyridine) 3 ((Cl) 2Ru).
Conclusiones:
- La descomposición de los catalizadores de la metátesis del rutenio es ligando-dependiente, con las fosfinas que juegan un papel clave en la formación de sales de metilfosfonio.
- El ataque nucleofílico por la fosfina es una probable vía de descomposición importante para estos catalizadores.
- Se necesita más investigación para identificar las especies de hidruro de rutenio formadas a partir de la descomposición del catalizador libre de fosfina.
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