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Complejos divalentes de lantánido metaloceno con una geometría de coordinación lineal y una mezcla orbital

K Randall McClain¹, Colin A Gould, David A Marchiori²

¹Research Department, Chemistry Division. US Navy, Naval Air Warfare Center, Weapons Division, China Lake, California 93555, United States.

Journal of the American Chemical Society

|November 23, 2022

Resumen

Los investigadores sintetizaron metallocenos lantánidos divalentes lineales, Ln ((pentaisopropylcyclopentadienyl) 2), expandiendo la serie conocida. Estos compuestos exhiben estructuras electrónicas únicas y una mezcla orbital s-d significativa, impactando las propiedades magnéticas.

Área de la Ciencia:

Química inorgánica
Química organometálica
Química de los lantánidos

Sus antecedentes:

Los compuestos de lantánidos divalentes con configuraciones 4f^5d₁ son raros.
La mayoría de los compuestos conocidos exhiben geometrías de coordinación trigonales.
Los metallocenos divalentes lineales Ln ((Cp^iPr5) ₂ fueron reportados previamente para Tb y Dy.

Objetivo del estudio:

Para sintetizar y caracterizar la serie completa de metallocenos divalentes lineales Ln ((Cp^iPr5) ₂ (1-Ln).
Investigar las configuraciones electrónicas y las propiedades estructurales de estos compuestos.
Para explorar las propiedades magnéticas e interacciones orbitales dentro de la serie.

Principales métodos:

Síntesis a través de las reacciones de metástasis y reducción de sales.
Caracterización mediante difracción de rayos X de un solo cristal y espectroscopia ultravioleta visible.
Espectroscopia de resonancia paramagnética de electrones para los compuestos de itrio (Y) y lantano (La).

Principales resultados:

Síntesis exitosa de toda la serie Ln ((Cp^iPr5) ₂, confirmando la geometría de coordinación lineal y la simetría pseudo-D_5.
Se establecieron configuraciones electrónicas 4f para Sm, Eu, Tm, Yb y 4f^{5d_{1 para otros lantánidos.}}
Se observó una mezcla orbital s-d significativa y se registraron constantes de acoplamiento hiperfino en los compuestos Y y La.

Conclusiones:

La geometría de coordinación lineal se mantiene en toda la serie divalente de lantánidos metallocenos.
La mezcla orbital 6s-5d pronunciada en estos compuestos lineales puede correlacionarse con el acoplamiento de espín 4f-5d más débil.
Este estudio amplía la comprensión de la química organometálica de los lantánidos divalentes y sus propiedades electrónicas.

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