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El "efecto de nitrosilo catalítico": la flexión de NO aumenta la eficiencia de las hidrogenaciones de alquenos a base

Yanfeng Jiang¹, Birgitta Schirmer, Olivier Blacque

¹Anorganisch-Chemisches Institut, Universität Zürich, Winterthurerstrasse 190, CH-8037, Zürich, Switzerland.

Journal of the American Chemical Society

|February 7, 2013

Resumen

Los nuevos complejos de renio ((I) catalizan la hidrogenación de alquenos con alta actividad y longevidad. Los estudios mecánicos revelan un nuevo ciclo de tipo Osborn que involucra la activación del sililio, la flexión del nitrosilo y la adición bifuncional de H2, lo que lleva a centros de renio superelectrófilos.

Área de la Ciencia:

Química organometálica Química orgánica de los metales.
La catálisis de la catálisis.
Reacciones de hidrogenación.

Sus antecedentes:

Los complejos de renio (I) se exploran para aplicaciones catalíticas.
El desarrollo de catalizadores eficientes y estables para la hidrogenación de alquenos es crucial en la síntesis orgánica.

Objetivo del estudio:

Para sintetizar y caracterizar los nuevos complejos diiodo rhenium ((I).
Para investigar su rendimiento catalítico en la hidrogenación de alquenos.
Para dilucidar el mecanismo de reacción utilizando estudios exhaustivos.

Principales métodos:

Síntesis y caracterización de los complejos diiodo rhenium (((I).
Hidrogenación catalítica de alquenos terminales e internos mediante cocatálisis con hidrosilano/B(C6F5) 3.
Estudios mecánicos que incluyen efectos de isótopos cinéticos, mezcla de H2 / D2, RMN VT y cálculos de DFT.

Principales resultados:

Los complejos preparados de renio exhiben una excelente actividad y longevidad en la hidrogenación de alquenos.
Los estudios mecánicos indican un ciclo de hidrogenación tipo Osborn con eliminación reductiva que determina la velocidad.
La activación implica la coordinación de cationes de silicio, la flexión de nitrosilo, la escisión heterolítica H-H y la protonación del ligando de fosfina, generando sitios vacantes para la catálisis.

Conclusiones:

Los nuevos complejos de renio ((I) son catalizadores de hidrogenación altamente efectivos.
El mecanismo propuesto destaca el papel de la flexión del nitrosilo y la pérdida de fosfina en la generación de centros de renio activos y superelectrofílicos.
Este trabajo proporciona información sobre el diseño de catalizadores organometálicos avanzados para la hidrogenación.

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