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Cinética de las reacciones de transferencia de electrones de los catalizadores de diglioxima de cobalto que

Jillian L Dempsey¹, Jay R Winkler, Harry B Gray

¹Beckman Institute, California Institute of Technology, Pasadena, California 91125, USA.

Journal of the American Chemical Society

|January 2, 2010

Resumen

Los complejos de cobalto diglyoxime catalizan eficientemente la evolución del hidrógeno (H2). La vía homolítica, que involucra a dos intermediarios de hidruro de cobalto, es favorecida sobre la vía heterolítica para la producción de H2.

Área de la Ciencia:

Química Inorgánica La Química Inorgánica es la química inorgánica.
La catálisis es la catálisis.
La electroquímica es electroquímica.

Sus antecedentes:

Los complejos de cobalto diglyoxime son catalizadores conocidos para la evolución del hidrógeno.
Comprender los mecanismos de reacción es crucial para optimizar la eficiencia catalítica.

Objetivo del estudio:

Para analizar las vías para la evolución del hidrógeno (H2) catalizado por complejos de cobalto diglyoxime.
Determinar el mecanismo favorecido entre las rutas heterolíticas y homolíticas.

Principales métodos:

Análisis cinético de los experimentos de apagado de flash láser.
Estimación de las constantes de velocidad y los parámetros de reorganización para las reacciones de autointercambio de cobalto (Co(III) -Co(II) y Co(II) -Co(I)).
Evaluación termodinámica y cinética de las vías de reacción propuestas.

Principales resultados:

Se identificaron dos vías para la producción de H2: heterolítico (a través de la protonación Co (III) -hidruro) y homolítico (a través de Co (III) -hidruro asociación).
Se cuantificaron las constantes de velocidad y las energías de reorganización para los pasos clave de transferencia de electrones.
Se encontró que la vía homolítica (2 Co ((III) H → 2 Co ((II) + H2) era kinética y termodinámicamente favorecida.

Conclusiones:

Los complejos de cobalto diglyoxime catalizan la evolución de H2 a través de un mecanismo dominado por el acoplamiento homolítico de especies de hidruro de cobalto.
Los hallazgos proporcionan información sobre el diseño de catalizadores moleculares eficientes para la producción de hidrógeno.

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