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Actínidos 2-metalabifenilenos que cumplen la regla de Hückel

Justin K Pagano^1,2, Jing Xie^3,4, Karla A Erickson¹

¹Chemistry Division, Los Alamos National Laboratory, Los Alamos, NM, USA.

|February 28, 2020

Resumen

Los investigadores sintetizaron los primeros compuestos de 2-metalabifenileno, con un anillo antiaromático de ciclobutadieno y un anillo aromático de benceno. Estas nuevas estructuras organometálicas muestran covalencia y deslocalización de los electrones f del uranio.

Área de la Ciencia:

Química organometálica
Química orgánica
Ciencias de los materiales

Sus antecedentes:

La aromaticidad y la antiaromaticidad son conceptos fundamentales en la química orgánica, ejemplificados por el bifenileno.
Las investigaciones anteriores sobre los análogos del bifenileno se centraron principalmente en los compuestos orgánicos.
Los intentos de sintetizar compuestos de metallabifenileno no han tenido éxito, produciendo otras estructuras complejas.

Objetivo del estudio:

Sintetizar y caracterizar nuevos compuestos de 2-metalabifenileno.
Investigar las propiedades electrónicas y las características estructurales de estos complejos de metallabifenileno.
Explorar el potencial de la covalencia y la deslocalización de electrones en estos nuevos sistemas organometálicos.

Principales métodos:

Síntesis de compuestos de 2-metalabifenileno.
Difracción de rayos X monocristalino para el análisis estructural.
Espectroscopia de resonancia magnética nuclear (RMN) y cálculos de desplazamiento químico independientes del núcleo (NICS) para la caracterización electrónica.
Cálculos del orbital molecular y del orbital de enlace natural (NBO) de Kohn-Sham para estudiar el comportamiento de los electrones.

Principales resultados:

Síntesis y caracterización exitosas de los primeros compuestos de 2-metalabifenileno.
El análisis estructural reveló triciclos metálicos de 11 miembros casi planos comparables al bifenileno.
Los datos espectroscópicos y computacionales confirmaron la presencia de un anillo antiaromático de ciclobutadieno y un anillo aromático de benceno.
Se observó evidencia de covalencia y deslocalización de electrones de uranio f2 con el ligando de carbono.

Conclusiones:

El estudio informa de la primera síntesis de compuestos de 2-metallabifenileno.
Estos compuestos presentan propiedades electrónicas únicas, incluida la antiaromaticidad en el anillo de ciclobutadieno y la aromaticidad en el anillo de benceno.
Los hallazgos demuestran una covalencia significativa y una deslocalización de electrones que involucra el centro metálico y el ligando orgánico.

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