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Desentrañar vías bifurcadas para la formación de CO y HCOOH: información de la espectroscopia FTIR de flujo detenido

Samir Chattopadhyay¹, Sudip Barman², Reiner Lomoth¹

¹Department of Chemistry─Ångström Laboratories, Uppsala University, SE 75120 Uppsala, Sweden.

Journal of the American Chemical Society

|June 18, 2025

Resumen

Los complejos de manganeso convierten eficientemente CO2 en CO. Una nueva investigación revela intermediarios en tiempo real para la conversión de CO2 en HCOOH, identificando un intermediario clave de hidrógeno de manganeso, pero también problemas de inestabilidad del catalizador.

Área de la Ciencia:

Química inorgánica
La electroquímica
Catálisis

Sus antecedentes:

Los complejos de tricarbonilo de bipiridina de manganeso son eficientes para la reducción electroquímica de CO2 (e-CO2RR) a CO.
El logro de la selectividad para la producción de HCOOH requiere la comprensión de las vías de reacción complejas.

Objetivo del estudio:

Proporcionar pruebas espectroscópicas directas de las vías de bifurcación en e-CO2RR.
Identificar los intermediarios clave en la conversión selectiva de CO2 en HCOOH mediante el uso de complejos de manganeso.

Principales métodos:

Se utilizó una mezcla de flujo detenido con un reductor de decametilcobaltoceno.
Se utiliza la espectroscopia de infrarrojos con resolución temporal (TRIR) para observar los intermedios de reacción en tiempo real.

Principales resultados:

Intermedios clave identificados en la vía de bifurcación para la reducción de CO2 a HCOOH.
Se han observado compuestos intermedios de Mn-hidruro y Mn-formato, validando las vías mecanicistas.
Las constantes de velocidad se alinean con las frecuencias de rotación electroquímica, lo que confirma su relevancia para e-CO2RR.

Conclusiones:

La producción de HCOOH implica la transferencia de protones a un centro de Mn reducido, formando un hidruro de Mn, seguido de la inserción de CO2.
La degradación del catalizador ocurre debido a la incapacidad del fenolato intermedio para volver a unir protones.
Las ideas mecánicas guían el diseño de catalizadores moleculares más estables y selectivos para la producción de HCOOH.

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