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 CuSnF 6 ‐dpds‐ sql (dpds = 4,4′'‐dipyridyldisulfide) with sql topology into rigid CuSnF 6 ‐dpds‐ cds with cds topology. Notably, the cds topology is unprecedented and first obtained in anion‐pillared MOF materials. As a result, rigid CuSnF 6 ‐dpds‐ cds exhibits enhanced C 2 H 2 adsorption capacity of 48.61 cm 3 g −1 at 0.01 bar compared to flexible CuSnF 6 ‐dpds ‐sql (21.06 cm 3 g −1 ). The topology transformation also facilitates the adsorption kinetics for C 2 H 2 , exhibiting a 6.5‐fold enhanced diffusion time constant (D/r 2 ) of 1.71 × 10 −3 s −1 on CuSnF 6 ‐dpds ‐cds than that of CuSnF 6 ‐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 C 2 H 4 (>99.996%) effluent with a productivity of 93.9 mmol g −1 can be directly collected from C 2 H 2 /C 2 H 4 (1/99, v/v) gas‐mixture in a single CuSnF 6 ‐dpds‐ cds column.