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Activación del amoníaco, evolución de H2 y formación de nitruro a partir de un complejo de molibdeno con un ligando

Grant W Margulieux¹, Máté J Bezdek¹, Zoë R Turner¹

¹Department of Chemistry, Princeton University , Princeton, New Jersey 08544, United States.

Journal of the American Chemical Society

|April 18, 2017

Resumen

Los complejos de molibdeno con ligandos de bis (imino) piridina activan el amoníaco, lo que conduce a la formación de dihidrógeno y permite la síntesis de nitritos terminales. Esta investigación revela una nueva vía de activación dual del amoníaco.

Área de la Ciencia:

Química organometálica
Catálisis
Química inorgánica

Sus antecedentes:

Los ligandos de bis (imino) piridina son andamios versátiles en la química de la coordinación.
Los complejos de molibdeno son conocidos por su actividad catalítica en varias transformaciones.
La activación del amoníaco es un paso crucial en muchos procesos industriales, incluida la producción de fertilizantes y la fijación de nitrógeno.

Objetivo del estudio:

Investigar la reactividad de los complejos de bis (imino) piridina y molibdeno con el amoníaco.
Explorar el mecanismo de activación del amoníaco y las transformaciones subsiguientes.
Desarrollar nuevas vías catalíticas para la oxidación del amoníaco y la síntesis de nitruro.

Principales métodos:

Síntesis y caracterización de los complejos de bis (imino) piridina y molibdeno.
Estudios de reordenamiento haptotrópico inducido por coordinación.
Investigación de la pérdida de ligando, la activación del enlace NH y la formación de dihidrógeno.
Caracterización cristalográfica de los principales productos intermedios.

Principales resultados:

Tratamiento de (iPrPDI) Mo ((η6-C6H6) con reordenamiento haptotrópico inducido por amoníaco para formar (iPrPDI) Mo ((NH3) 2) ((η2-C6H6).
Se sintetizaron complejos análogos de etileno y ciclohexeno, con este último caracterizado cristalográficamente.
Todos los complejos sufrieron pérdida de ligando, activación del enlace N-H y pérdida de H2, lo que indica una vía de activación dual de amoníaco.
Se sintetizó un nitruro terminal a partir de amoníaco coordinado a través de la abstracción de átomos de hidrógeno, un paso clave en la oxidación de NH3.

Conclusiones:

Se descubrió un nuevo mecanismo de activación dual de amoníaco que involucra la cooperatividad M-L y el debilitamiento del enlace inducido por la coordinación.
El estudio demuestra el potencial de los complejos de bis (imino) piridina molibdeno en las transformaciones catalíticas de amoníaco.
La síntesis de un nitruro terminal a partir del amoníaco pone de relieve una nueva ruta hacia la oxidación del amoníaco.

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