Comprehensive Pore Tuning in an Ultrastable Fluorinated Anion Cross‐Linked Cage‐Like MOF for Simultaneous Benchmark Propyne Recovery and Propylene Purification

Propyne/propylene (C3H4/C3H6) separation is an important but challenging industrial process to produce polymer‐grade C3H6 and recover high‐purity C3H4. Herein, we report an ultrastable TiF62− anion cross‐linked metal–organic framework (ZNU‐2) with precisely controlled pore size, shape and functionality for benchmark C3H4 storage (3.9/7.7 mmol g−1 at 0.01/1.0 bar and 298 K) and record high C3H4/C3H6 (10/90) separation potential (31.0 mol kg−1). The remarkable C3H4/C3H6 (1/99, 10/90, 50/50) separation performance was fully demonstrated by simulated and experimental breakthroughs under various conditions with excellent recyclability and high productivity (42 mol kg−1) of polymer‐grade C3H6 from a 1/99 C3H4/C3H6 mixture. A modelling study revealed that the symmetrical spatial distribution of six TiF62− on the icosahedral cage surface provides two distinct binding sites for C3H4 adsorption: one serves as a tailored single C3H4 molecule trap and the other boosts C3H4 accommodation by cooperative host–guest and guest–guest interactions. An unprecedented ultrastable fluorinated anion cross‐linked cage‐like MOF (ZNU‐2) was prepared for benchmark propyne/propylene separation with large C3H4 capacity (7.7 mmol g−1), high C3H4/C3H6 selectivity (16.2), low adsorption enthalpy (43.0 kJ mol−1) and high practical C3H4 and C3H6 productivity due to the precise control of pore size, shape and functionality.