Los iones metálicos alcalinos dictan la estructura y la reactividad de un complejo de imido de hierro
Yafei Gao1, Maren Pink1, Jeremy M Smith1
1Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States.
Journal of the American Chemical Society
|January 25, 2022
Resumen
Los iones de metales alcalinos que se coordinan con los complejos de imido de hierro influyen en la longitud del enlace Fe = N y la basicidad del ligando de imido. Esta coordinación dirige la reactividad, impactando reacciones como la transferencia de átomos de hidrógeno y las transformaciones de benzofenona.
Área de la Ciencia:
- Química organometálica
- Química de coordinación
- Química inorgánica
Sus antecedentes:
- Se propone que los iones metálicos sin redox modulen la reactividad de enlaces múltiples entre metales y ligandos.
- Existen datos limitados sobre las relaciones estructura-función de estos sistemas.
- Los complejos de imido de hierro son intermediarios clave en varios ciclos catalíticos.
Objetivo del estudio:
- Investigar los efectos estructurales y electrónicos de la coordinación de iones de metales alcalinos en un complejo de imido de hierro.
- Comprender cómo la coordinación de metales alcalinos influye en la reactividad del ligando imido y las transformaciones posteriores.
- Establecer relaciones estructura-actividad para complejos de imido de hierro en reacciones como la transferencia de átomos de hidrógeno (HAT).
Principales métodos:
- Síntesis y caracterización estructural de una serie de complejos de imido Fe (II) con metales alcalinos coordinados (Li, Na, K) mediante cristalografía de rayos X.
- Estudios experimentales que incluyen protonación, alquilación y reacciones con 1,4-ciclohexadieno y benzofenona.
- Estudios computacionales para analizar la estructura electrónica, la polarización de enlaces Fe=N y la basicidad del ligando imido.
Principales resultados:
- Se obtuvieron complejos de imido Fe (II) estructuralmente caracterizados con iones Li, Na y K coordinados.
- La coordinación del metal alcalino alarga modestamente el enlace Fe = N, con el efecto inversamente proporcional al tamaño del ion del metal alcalino.
- La basicidad del ligando imido aumenta con la coordinación de metales alcalinos (Li > K ≈ Na), lo que influye en la reactividad en las reacciones de HAT y benzofenona.
Conclusiones:
- La coordinación de iones de metales alcalinos dicta significativamente la estructura y la reactividad de los ligandos de imido de hierro.
- La basicidad del ligando imido, modulada por la coordinación del metal alcalino, controla las vías y las velocidades de reacción.
- Estos hallazgos ponen de relieve el papel de los metales alcalinos en la dirección de la reactividad de los intermedios organometálicos.
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