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Aislamiento de complejos mononucleares neutros de cobre estabilizados por dos carbenos cíclicos (alquilo) y amino)

David S Weinberger¹, Nurul Amin Sk, Kartik Chandra Mondal

¹UCSD-CNRS Joint Research Chemistry Laboratory (UMI 3555), Department of Chemistry and Biochemistry, University of California-San Diego , La Jolla, California 92093-0343, United States.

Journal of the American Chemical Society

|April 16, 2014

Resumen

Se sintetizaron dos nuevos complejos de cobre de dos coordenadas ((0)) estabilizados por carbenos. Estos compuestos sensibles al aire exhiben propiedades electrónicas únicas, con el electrón no apareado deslocalizado sobre los ligandos de carbenos, confirmado por la espectroscopia EPR.

Área de la Ciencia:

Química organometálica Química orgánica de los metales.
Coordinación Química de la Coordinación
Ciencia de los materiales Ciencia de los materiales.

Sus antecedentes:

Los complejos de cobre son vitales en la catálisis y la ciencia de los materiales.
La estabilización de las especies de cobre de baja valencia presenta desafíos sintéticos.
Los carbenos N-heterocíclicos (NHC) son ligandos efectivos para estabilizar los centros metálicos.

Objetivo del estudio:

Para sintetizar y caracterizar nuevos complejos de cobre de dos coordenadas ((0)).
Para investigar la estructura electrónica y la unión en estos complejos únicos.
Explorar la estabilidad y las propiedades de los sistemas de cobre-carbenos.

Principales métodos:

Síntesis de complejos de cobre utilizando agentes reductores y precursores de carbenos.
Purificación y caracterización de compuestos sensibles al aire y a la humedad.
Cálculos de la Teoría Funcional de Densidad (DFT) para aclarar la estructura electrónica.
Espectroscopia de resonancia paramagnética de electrones (EPR) para confirmar la deslocalización de electrones.

Principales resultados:

Se sintetizaron con éxito dos complejos distintos de (carbeno) 2Cu.
El centro de cobre está en el estado de oxidación formal cero con una configuración electrónica d(10).
El electrón no emparejado está deslocalizado a través de los ligandos de carbenos, no localizado en el cobre.
Los espectros de EPR confirmaron el acoplamiento hiperfino con isótopos de cobre, nitrógeno y núcleos de hidrógeno.

Conclusiones:

Se han preparado nuevos y estables complejos de dos coordenadas de cobre (((0) soportados por carbenos.
Estos complejos exhiben estructuras electrónicas inusuales con electrones no apareados deslocalizados.
Los hallazgos avanzan en la comprensión de las interacciones entre metales de baja valencia y carbenos y su estabilidad.

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