Interpenetration Symmetry Control Within Ultramicroporous Robust Boron Cluster Hybrid MOFs for Benchmark Purification of Acetylene from Carbon Dioxide

The separation of C₂H₂/CO₂ is an important process in industry but challenged by the trade-off of capacity and selectivity owning to their similar physical properties and identical kinetic molecular size. We report the first example of symmetrically interpenetrated dodecaborate pillared MOF, ZNU-1, for benchmark selective separation of C₂H₂ from CO₂ with a high C₂H₂ capacity of 76.3 cm³ g-¹ and record C²H²/CO² selectivity of 56.6 (298 K, 1 bar) among all the robust porous materials without open metal sites. Single crystal structure analysis and modeling indicated that the interpenetration shifting from asymmetric to symmetric mode provided optimal pore chemistry with ideal synergistic "2+2'' dihydrogen bonding sites for tight C₂H₂ trapping. The exceptional separation performance was further evidenced by simulated and experimental breakthroughs with excellent recyclability and high productivity (2.4 mol kg^-1) of 99.5 % purity C₂H₂ during stepped desorption process.