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

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-dpds-sql (dpds = 4,4''-dipyridyldisulfide) with sql topology into rigid CuSnF-dpds-cds with cds topology. Notably, the cds topology is unprecedented and first obtained in anion-pillared MOF materials. As a result, rigid CuSnF-dpds-cds exhibits enhanced CH adsorption capacity of 48.61 cm g at 0.01 bar compared to flexible CuSnF-dpds-sql (21.06 cm g). The topology transformation also facilitates the adsorption kinetics for CH, exhibiting a 6.5-fold enhanced diffusion time constant (D/r) of 1.71 × 10 s on CuSnF-dpds-cds than that of CuSnF-dpds-sql (2.64 × 10 s). Multiple computational simulations reveal the structural transformations and guest-host interactions in both adsorbents. Furthermore, dynamic breakthrough experiments demonstrate that high-purity CH (>99.996%) effluent with a productivity of 93.9 mmol g can be directly collected from CH/CH (1/99, v/v) gas-mixture in a single CuSnF-dpds-cds column.