Boosting Adsorption and Selectivity of Acetylene by Nitro Functionalisation in Copper(II)‐Based Metal–Organic Frameworks

• Published in: Angewandte Chemie International Edition 2025-02, Vol.64 (6), p.e202417183-n/a
• Main Authors: Guo, Lixia, Han, Xue, Li, Jiangnan, Li, Weiyao, Chen, Yinlin, Manuel, Pascal, Schröder, Martin, Yang, Sihai
• Format: Article
• Language: English
• Subjects: Acetylene; Adsorption; Carbon dioxide; Communication; Copper; Functional groups; Metal-organic frameworks; Neutron diffraction; Nitrogen dioxide
• ISSN: 1433-7851; 1521-3773; 1521-3773
• DOI: 10.1002/anie.202417183

Purification and storage of acetylene (C2H2) are important to many industrial processes. The exploitation of metal–organic framework (MOF) materials to address the balance between selectivity for C2H2 vs carbon dioxide (CO2) against maximising uptake of C2H2 has attracted much interest. Herein, we report that the synergy between unsaturated Cu(II) sites and functional groups, fluoro (−F), methyl (−CH3), nitro (−NO2) in a series of isostructural MOF materials MFM‐190(R) that show exceptional adsorption and selectivity of C2H2. At 298 K, MFM‐190(NO2) exhibits an C2H2 uptake of 216 cm3 g−1 (320 cm3 g−1 at 273 K) at 1.0 bar and a high selectivity for C2H2/CO2 (up to ~150 for v/v = 2/1) relevant to that in the industrial cracking stream. Dynamic breakthrough studies validate and confirm the excellent separation of C2H2/CO2 by MFM‐190(NO2) under ambient conditions. In situ neutron powder diffraction reveals the cooperative binding, packing and selectivity of C2H2 by unsaturated Cu(II) sites and free −NO2 groups. The isostructural MOF materials, MFM‐190(R) (R=−F, −CH3, −NO2) exhibit exceptional acetylene (C2H2) adsorption and selectivity. MFM‐190(NO2) shows a high C2H2 uptake of 216 cm3 g−1 at 1 bar, 298 K and excellent C2H2/CO2 selectivity (up to ~150 for v/v = 2/1). Dynamic breakthrough experiments confirm efficient separation under ambient conditions, supported by in situ neutron powder diffraction studies revealing cooperative binding of C2H2 at unsaturated Cu(II) and −NO2 sites.