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Abstract The efficient separation of acetylene (C 2 H 2 ) from carbon dioxide (CO 2 ) and ethylene (C 2 H 4 ) is of significant industrial importance but remains highly challenging due to their similar physicochemical properties. In this study, three isostructural metal–organic frameworks, Co 4 ( µ 4 ‐SO 4 ) 2 (tpim) 2 (L) 2 (tpim = 2,4,5‐tri(4‐pyridyl)‐imidazole, L = dicarboxylate; termed as Co 4 ‐L), are constructed from sulfate‐capped Co 4 clusters extended by N‐rich tpim linkers and different‐sized dicarboxylate ligands. Among them, the Co₄‐1,4‐ndc framework, incorporating 1,4‐naphthalenedicarboxylic acid (1,4‐ndc), offers optimal pore confinement that promotes host–guest interactions between C₂H₂ molecules and framework. This material exhibits high C₂H₂ capture capacities of 4.30 and 3.40 mmol g − ¹ from equimolar C₂H₂/CO₂ and C₂H₂/C₂H₄ mixtures, respectively. Theoretical simulations reveal that the enhanced selectivity arises from multiple cooperative hydrogen‐bonding interactions between C₂H₂ and the framework Co₄‐1,4‐ndc , generating strong and preferential binding sites. This study highlights the role of pore‐environment engineering of metal‐organic frameworks (MOFs) for selective C₂H₂ separation, providing a foundation for the development of advanced adsorbents in industrial gas purification.
Zhou et al. (Sat,) studied this question.