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Imine Metathesis by Silica-Supported Catalysts Using the Methodology of Surface Organometallic Chemistry
Published on: October 18, 2019
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Un análogo de silicio estabilizado por NHC del ion acilio: síntesis, estructura, reactividad y estudios teóricos
Syed Usman Ahmad1, Tibor Szilvási2, Elisabeth Irran1
1†Institut für Chemie, Technische Universität Berlin, Straße des 17. Juni 135, Sekr. C2, D-10623 Berlin, Germany.
Journal of the American Chemical Society
|April 15, 2015
Resumen
Los investigadores sintetizaron nuevos análogos de silicio de los iones de acilio, los iones sila-acilio, mediante la reducción de dióxido de carbono. Estos compuestos reaccionan con el agua para formar diferentes estructuras de anillo de silicio-oxígeno, dependiendo de la voluminosidad del sustituto.
Área de la Ciencia:
- Química del organosilicio Química del organosilicio
- Grupo Principal Química.
- Utilización del dióxido de carbono Utilización del dióxido de carbono
Sus antecedentes:
- Los iones acilio son importantes intermediarios sintéticos.
- Los análogos de silicio ofrecen una reactividad y posibilidades estructurales únicas.
- Los carbenos N-heterocíclicos (NHC) son ligandos versátiles para estabilizar las especies reactivas.
Objetivo del estudio:
- Para sintetizar y caracterizar nuevos iones de sila-acilio.
- Para investigar la reactividad de los iones sila-acilio con el agua.
- Explorar la influencia de la masa estérica en los resultados de la reacción y las estructuras del producto.
Principales métodos:
- Síntesis de cationes de sililiumilideno y posterior formación de iones sila-acilio.
- Reacción de iones de sila-acilio con el agua.
- Caracterización estructural utilizando cristalografía de rayos X y métodos espectroscópicos.
- Estudios computacionales utilizando la Teoría Funcional de la Densidad (DFT).
- Espectrometría de masas para la identificación intermedia.
Principales resultados:
- Síntesis exitosa de iones de sila-acilio [RSi(O) ((NHC) 2Cl estabilizado por los ligandos del NHC.
- La reacción con el agua produjo diferentes estructuras de anillos de silicio-oxígeno basadas en el sustituto de arilo.
- El compuesto 2a formó un análogo dimérico de carboxilato, mientras que el 2b produjo un dianión ciclotetrasiloxanediol.
- Los cálculos de DFT confirmaron un fuerte carácter de doble enlace Si=O en los iones de sila-acilio y enlaces iónicos de Si-O en los productos.
- Se aclararon conocimientos mecánicos sobre la formación de anillos (SiO) n.
Conclusiones:
- Los iones sila-acilio son objetivos sintéticos accesibles a través de la reducción de CO2.
- Los efectos estéricos de los sustituyentes juegan un papel crucial en la dirección de los productos de hidrólisis.
- El estudio proporciona una comprensión más profunda de la formación de enlaces silicio-oxígeno y el ensamblaje del sistema de anillos.
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