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Variaciones de coordinación dentro de las especies de cobre derivado de dióxido de oxígeno (hidro) peroxo y

Pradip Kumar Hota¹, Anex Jose², Sanjib Panda¹

¹Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States.

Journal of the American Chemical Society

|April 30, 2024

Resumen

Este estudio detalla la química del cobre y el oxígeno, caracterizando las especies de dicobre (II) peroxo, hidroperoxo y superoxo. Se aclararon las propiedades termodinámicas y espectroscópicas, ofreciendo información sobre los procesos redox mediados por cobre.

Área de la Ciencia:

Química inorgánica
Química bioorgánica
Química de coordinación

Sus antecedentes:

Los iones de cobre son cruciales en los procesos redox, incluida la unión y reducción de oxígeno.
Comprender la termodinámica de las interacciones cobre-oxígeno es vital para elucidar los mecanismos bioquímicos.

Objetivo del estudio:

Para sintetizar y caracterizar varias especies de cobre-oxígeno.
Investigar las relaciones termodinámicas y las propiedades espectroscópicas de estos complejos.
Explorar el papel del marco de ligando en la modulación de la reactividad cobre-oxígeno.

Principales métodos:

Adición criogénica de dioxígeno a un complejo de dicobre.
Caracterización mediante UV-vis, resonancia Raman, espectroscopia EPR y espectrometría de masas.
Cálculos DFT y mediciones electroquímicas para el análisis termodinámico.

Principales resultados:

Formación y caracterización de las especies de dicobre (II) peroxo, hidroperoxo y superoxo.
Explicación del espectro EPR para las especies superoxo a través de un sistema frustrado de tres espines.
Determinación del potencial redox (E°' = -0,44 ± 0,01 V frente a Fc^+/0) y el equilibrio ácido-base (pKa = 22,3 ± 0,7).
Cálculo de la energía libre de disociación del enlace O-H (BDFE_OO-H = 80,3 ± 1,2 kcal/mol).

Conclusiones:

El estudio proporciona un perfil termodinámico y espectroscópico completo de los aductos de cobre-oxígeno.
Las variaciones en el tamaño del anillo de quelato de ligandos influyen en las propiedades de estos complejos de cobre.
La acidez de Lewis mejorada está relacionada con las propiedades observadas.

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