Cyano-bifunctional MOFs as superior catalysts for carbon dioxide fixation under co-catalyst and solvent free conditions

In the present work, a strategy for the incorporation of nitrogen-rich units to an unsaturated Cr-based MOF, MIL100-Cr, is reported. Based on this strategy, various cyanide functional groups (diamino malononitrile, 1,3-phenylene diacetonitrile, and malononitrile) were incorporated into the framework and utilized as exceptional catalysts in the carbon dioxide fixation under mild, solvent, and co-catalyst free conditions. This is the first report on the application of cyano-bifunctional frameworks in cycloaddition reaction. The contemporaneous presence of accessible Lewis acid sites and pendent cyanide groups results in highly striking conversion and TON even for bulky and large substrates. High tendency and strong interaction of cyanide groups with CO2 cause a synergetic effect in the performance of the catalysts. The role of different cyanide groups applied in this work has also been studied. The reaction wouldn't proceed in the presence of pristine MOF without co-catalyst addition.

Automated summary

A strategy for incorporating nitrogen-rich units into the Cr-based MOF, MIL100-Cr, was reported, with various cyanide functional groups being utilized as efficient catalysts for carbon dioxide fixation. The presence of Lewis acid sites and cyanide groups in the framework led to high conversion rates and TON, especially for bulky substrates. The strong interaction between cyanide groups and CO2 resulted in a synergistic effect on the catalyst performance.