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 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.