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Acoplamiento vinilo-vinilo en metales de transición tardía a través del mecanismo de eliminación reductora C-C. Un

Valentine P Ananikov¹, Djamaladdin G Musaev, Keiji Morokuma

¹N. D. Zelinsky Institute of Organic Chemistry, RAS, Leninsky Prospect 47, Moscow 117913, Russia.

Journal of the American Chemical Society

|March 14, 2002

Resumen

Este estudio detalla la reacción de eliminación reductiva vinilo-vinilo en complejos metálicos. Los complejos de paladio y platino muestran una actividad variable, influenciada por ligandos y factores estéricos, que afectan la formación de enlaces C-C.

Área de la Ciencia:

Química organometálica Química orgánica de los metales.
Química computacional es la química computacional.
Mecanismo de reacción Estudios Estudios sobre el mecanismo de reacción

Sus antecedentes:

La eliminación reductiva vinilo-vinilo es un paso clave en muchos ciclos catalíticos.
La comprensión de los factores que influyen en esta reacción es crucial para el diseño del catalizador.
Los complejos bis-sigma-vinilo sirven como sistemas modelo para el estudio de la formación de enlaces C-C.

Objetivo del estudio:

Para investigar la reacción de eliminación reductiva vinilo-vinilo utilizando la teoría funcional de la densidad.
Para determinar la actividad relativa de varios complejos metálicos (Pd, Pt, Rh, Ir, Ru, Os).
Para analizar la influencia de los ligandos (X) y los efectos estéricos en las barreras de reacción y la estereoselectividad.

Principales métodos:

Cálculos detallados de la teoría funcional de la densidad (DFT).
Análisis de las superficies de energía (DeltaE, DeltaH, DeltaG, DeltaG(aq)).
Investigación de los efectos de los disolventes en las vías de reacción.

Principales resultados:

Se establece el orden de actividad: Pd(IV), Pd(II) > Pt(IV), Pt(II), Rh(III) > Ir(III), Ru(II), Os(II).
Efecto del ligando en las barreras de activación (formación de enlaces C-C): Cl > Br, NH(3) > I > PH(3).
Factores identificados que controlan la estereoselectividad y las posibles vías de acoplamiento asimétrico.

Conclusiones:

La identidad del metal y la elección del ligando modulan significativamente las tasas de eliminación vinilo-vinilo reductoras.
Los disolventes polares pueden mejorar la eliminación reductora de complejos halógenos.
DFT proporciona información valiosa sobre los mecanismos de reacción y los resultados estereoquímicos en la catálisis organometálica.

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