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

Abstract

AbstractFlexible 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.