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Comportamiento de adsorción divergente controlado por aniones de esfera de coordinación primaria en el marco

Julius J Oppenheim¹, Jenna L Mancuso², Ashley M Wright¹

¹Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue Cambridge, Massachusetts 02139, United States.

Journal of the American Chemical Society

|October 1, 2021

Resumen

El monóxido de carbono (CO) y el etileno exhiben comportamientos únicos de adsorción en materiales Ni2X2BTDD con intercambio aniónico. Este estudio revela mecanismos de interacción distintos, cruciales para el diseño de marcos metálico-orgánicos avanzados (MOF) para la sorción selectiva de gases.

Área de la Ciencia:

Ciencias de los materiales
Química
Nanotecnología

Sus antecedentes:

Las estructuras metálicas orgánicas (MOF) son materiales porosos con estructuras sintonizables para la adsorción de gases.
La comprensión de los mecanismos de absorción de gases en los MOF es esencial para el desarrollo de tecnologías de separación selectiva.
Los materiales Ni2X2BTDD con intercambio aniónico ofrecen una plataforma para estudiar las interacciones fundamentales gas-ligando.

Objetivo del estudio:

Investigar las entalpias de adsorción de CO, etileno y H2 en materiales de Ni2X2BTDD con intercambio aniónico.
Para aclarar los mecanismos subyacentes responsables de los comportamientos divergentes de adsorción de gases.
Proporcionar información para el diseño racional de los MOF para las separaciones de gases específicas.

Principales métodos:

Síntesis de una serie de materiales Ni2X2BTDD con intercambio aniónico (X = OH, F, Cl, Br).
Medición de las entalpías de adsorción para el CO, el etileno y el H2.
Modelado computacional y análisis espectroscópico para determinar los mecanismos de interacción.

Principales resultados:

Se han observado entalpias de adsorción divergentes para el CO, el etileno y el H2, que se desvían del comportamiento típico del MOF.
Se identificó una interacción predominantemente σ-donante para el CO con centros de Ni2+.
Se determinó una interacción del receptor π para el etileno con centros de Ni2+, lo que explica las diferencias observadas.

Conclusiones:

Los distintos comportamientos de adsorción de CO y etileno se atribuyen a las diferencias en sus interacciones electrónicas con los sitios de Ni2+.
Estos hallazgos desafían la comprensión convencional de las tendencias de absorción de gases en los MOF.
El estudio proporciona una base para el diseño de MOF con selectividad controlada a través de la modificación postsinética.

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