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Hidritos de puente paramagnéticos de relevancia para la evolución del hidrógeno catalítico en los centros de

Aušra Jablonskytė¹, Joseph A Wright, Shirley A Fairhurst

¹Energy Materials Laboratory, School of Chemistry, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK.

Journal of the American Chemical Society

|November 1, 2011

Resumen

Los investigadores han caracterizado espectroscópicamente los hidritos puentes paramagnéticos, intermedios clave en los procesos relacionados con el hidrógeno. Este estudio revela una especie paramagnética estable, deslocalizada de valencia, formada a través de la transferencia de electrones a un complejo di-dihiolato de hierro.

Área de la Ciencia:

Química Inorgánica La Química Inorgánica es la química inorgánica.
Química bioorgánica Química bioorgánica.
La espectroscopia es una técnica de espectroscopia.

Sus antecedentes:

Los hidruros paramagnéticos están implicados como intermediarios en la evolución biológica y química del hidrógeno.
La caracterización de estas especies es crucial para comprender los mecanismos catalíticos relacionados con el hidrógeno.

Objetivo del estudio:

Proporcionar la primera caracterización espectroscópica de hidritos puente paramagnéticos bien definidos.
Investigar la estructura electrónica y las propiedades de dichas especies.

Principales métodos:

Espectro electroquímico FTIR con resolución temporal en una escala de tiempo de subsegundos.
Cálculos de la Teoría Funcional de la Densidad (DFT).
Espectroscopia de resonancia paramagnética de electrones (EPR) utilizando tanto hidrógeno (1H) como deuterio (2H).

Principales resultados:

La transferencia de un solo electrón a un complejo di-dihiolato de hierro (1) generó una especie de 37 electrones, deslocalizada por valencia.
No se observó una reorganización estructural significativa de la esfera de coordinación.
Las mediciones de EPR confirmaron la formación de un complejo paramagnético S = 1⁄2 (g = 2.0066).
Se encontró que la densidad de espín no emparejada se distribuye simétricamente entre los dos átomos de hierro.
Se observó un fuerte acoplamiento hiperfino con el hidruro puente (A(iso) = -75.8 MHz).

Conclusiones:

Este trabajo presenta la primera evidencia espectroscópica de hidritos puente paramagnéticos bien definidos.
La especie caracterizada es un complejo paramagnético estable y deslocalizado de valencia.
Los hallazgos avanzan en la comprensión de los intermediarios de hidruro en sistemas catalíticos.

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