Finely Pore‐Engineered Ultra‐Stable Cluster–Cluster‐type Metal–Organic Frameworks with Shifting One‐Step Ethylene Purification

Abstract One‐step ethylene (C₂H₄) purification from multicomponent mixtures to obtain polymerized grade C₂H₄ is vital in industry but still difficult to achieve. Herein untramicropore engineering is demonstrated in unique cluster–cluster‐type metal–organic framework (CCMOF) adsorbents (SNNU‐107‐X, X = OH/Cl/F) with shifting one‐step ethylene purification from the ternary mixture. Triangular prismic [Cd₈(TAZ)₉] and hollow hexagonal prismic [Cd₄₂(TAZ)₄₂] clusters (TAZ = tetrazolate) connect each other directly without inter‐cluster linkers to generate SNNU‐107‐X CCMOFs with fixed hexagonal large pore and alterable quadrilateral small pore. It is curious that these unique CCMOFs can keep their 3D porous frameworks in aqueous solution with pH = 2–13 for 30 days and even in boiling water for 15 days. Regulated by terminal coordinated anions (OH/Cl/F) located in quadrilateral pores, SNNU‐107‐X exhibits controllable and shifting ethylene adsorption and separation performance. In particular, SNNU‐107‐F can separate 99.999% C₂H₄ from C₂H₂/CO₂/C₂H₄ ternary mixture with a productivity of 274.4 L kg⁻¹ by one‐step process superior to almost all advanced materials. The time‐dependent kinetic adsorption, in situ FT‐IR spectra, DFT, and GCMC calculations indicate that the shifting ethylene separation of SNNU‐107‐X is ascribed to a thermodynamic and dynamic coupling effect modulated by single terminal anions in the ultramicropore space.