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La ciclodimerización catalizada por [Ni(0) L] del 1,3-butadieno: una investigación funcional de densidad integral
1Institut für Anorganische Chemie der Martin-Luther-Universität Halle-Wittenberg, Fachbereich Chemie, Kurt-Mothes-Strasse 2, D-06120 Halle, Germany. tobisch@chemie.uni-halle.de
Journal of the American Chemical Society
|April 25, 2002
Resumen
Este estudio investiga la ciclodimerización del butadieno utilizando un catalizador de níquel. La eliminación reductiva es el paso que determina la velocidad, influyendo en la selectividad del producto a través de factores termodinámicos y cinéticos.
Área de la Ciencia:
- Química organometálica Química orgánica de los metales.
- La catálisis es la catálisis.
- Química computacional es la química computacional.
Sus antecedentes:
- La ciclodimerización del butadieno es una reacción clave en la síntesis orgánica.
- Los catalizadores de níquel son ampliamente utilizados para las transformaciones de olefinas.
- La comprensión de los mecanismos de reacción es crucial para el diseño de catalizadores.
Objetivo del estudio:
- Para dilucidar el mecanismo de la ciclodimerización del butadieno catalizado por [bis (((butadieno) Ni (((0) PH ((3))).
- Para identificar el paso que determina la tasa y los factores que influyen en la selectividad del producto.
- Para explorar posibles vías de reacción y productos intermedios.
Principales métodos:
- Cálculos de la Teoría Funcional de Densidad (DFT) con corrección de gradiente.
- Análisis de las etapas elementales: acoplamiento oxidativo, eliminación reductora y isomerización alílica.
- Investigación del control estereoquímico en las etapas catalíticas.
Principales resultados:
- El acoplamiento oxidativo y la eliminación reductora ocurren con un estereocontrol distinto, lo que requiere isomerización.
- La eliminación reductiva es el paso global para determinar la tasa.
- Los principales productos (VCH, cis-1,2-DVCB, cis, cis-COD) se forman a través de vías competidoras.
- 1) Las especies no son intermediarios críticos en la vía principal.
Conclusiones:
- El mecanismo implica ajustes estereoquímicos y una eliminación reductiva que limita la velocidad.
- La selectividad del producto se puede ajustar mediante control termodinámico y cinético.
- El estudio proporciona información sobre la ciclodimerización del butadieno catalizado por el níquel.
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