π-stacked organic frameworks with captured ammonia for benzamide synthesis

Abstract

Ammonia (NH3) is a carbon-free energy carrier with great potential for sustainable energy systems. However, current NH3 capture materials still suffer from poor selectivity and capacity. Herein, we systematically engineered pyridine-derived π-stacked organic frameworks (πOFs), forming four crystalline materials (πOF-bpe, πOF-vdp, πOF-epp and πOF-pyp). Among these, πOF-bpe exhibited exceptional NH3 storage (8.81 mmol·g-1) and release properties. Furthermore, the as-synthesized πOF-bpe could serve as a solid reagent to provide NH3 source in the synthesis of benzamide from benzoyl chloride. Structural characterization and computational analysis confirmed that πOF-bpe's excellent selective for NH3 capture is attributed to specific N-H···N hydrogen bonds and a hierarchical hydrogen-bonding network. This pioneering research not only highlights the potential of πOFs for efficient NH3 capture, but also provides new insights into designing supramolecular frameworks for NH3 utilization in organic transformations.