Topology Reconfiguration of Anion‐Pillared Metal–Organic Framework from Flexibility to Rigidity for Enhanced Acetylene Separation

Abstract Flexible metal–organic framework (MOF) adsorbents commonly encounter limitations in removing trace impurities below gate‐opening threshold pressures. Topology reconfiguration can fundamentally eliminate intrinsic structural flexibility, yet remains a formidable challenge and is rarely achieved in practical applications. Herein, a solvent‐mediated approach is presented to regulate the flexible CuSnF₆‐dpds‐sql (dpds = 4,4′'‐dipyridyldisulfide) with sql topology into rigid CuSnF₆‐dpds‐cds with cds topology. Notably, the cds topology is unprecedented and first obtained in anion‐pillared MOF materials. As a result, rigid CuSnF₆‐dpds‐cds exhibits enhanced C₂H₂ adsorption capacity of 48.61 cm³ g⁻¹ at 0.01 bar compared to flexible CuSnF₆‐dpds‐sql (21.06 cm³ g⁻¹). The topology transformation also facilitates the adsorption kinetics for C₂H₂, exhibiting a 6.5‐fold enhanced diffusion time constant (D/r²) of 1.71 × 10⁻³ s⁻¹ on CuSnF₆‐dpds‐cds than that of CuSnF₆‐dpds‐sql (2.64 × 10⁻⁴ s⁻¹). Multiple computational simulations reveal the structural transformations and guest–host interactions in both adsorbents. Furthermore, dynamic breakthrough experiments demonstrate that high‐purity C₂H₄ (>99.996%) effluent with a productivity of 93.9 mmol g⁻¹ can be directly collected from C₂H₂/C₂H₄ (1/99, v/v) gas‐mixture in a single CuSnF₆‐dpds‐cds column.