Aromaticity Regulation in Isostructural Metal-Organic Frameworks for Propyne Storage and Propylene Purification

We report the exceptional propyne (C₃H₄) storage and propylene (C₃H₆) purification in a metal-organic framework, PKU-101, controlled via regulation of aromaticity. The pyrene-fused pore interior of PKU-101 provides multiple C─H···π interactions for alkyne, resulting in a record C₃H₄ adsorption of 250 cm³ cm^-3 at 298 K and 1 bar, representing a benchmark sorbent for C₃H₄. Additionally, the supramolecular interactions enable fine thermodynamic discrimination for alkenes, resulting in excellent separation of C₂H₄/C₃H₆ (v/v = 1/1), delivering simultaneously high productivities of C₃H₆ and C₂H₄ (267 and 174 L kg^-1, respectively; C₂H₄ purity > 99.9 %). Effective separation of C₃H₆/C₃H₈ (v/v = 1/1) and C₃H₄/C₃H₆ (v/v = 1/99) with a high C₃H₆ productivity of 532 L kg^-1 (purity of 99.99 %) has also been achieved by PKU-101. In situ crystallographic and spectroscopic studies confirmed the key role of enhanced aromaticity on the discrimination of alkanes/alkenes/alkynes. Importantly, these weak supramolecular interactions enable complete regeneration at only 318 K.