Fine-Tuning the Pore Environment of the Microporous Cu-MOF for High Propylene Storage and Efficient Separation of Light Hydrocarbons

[Image: see text] Ethylene (C(2)H(4)) and propylene (C(3)H(6)) are important energy sources and raw materials in the chemical industry. Storage and separation of C(2)H(4) and C(3)H(6) are vital to their practical application. Metal–organic frameworks (MOFs) having adjustable structures and pore environments are promising candidates for C(3)H(6)/C(2)H(4) separation. Herein, we obtained a Cu-based MOF synthesized by H(3)TTCA and pyrazine ligands. By adding different functional groups on the ligands within the MOFs, their pore environments are adjusted, and thus, the C(3)H(6) storage capacity and C(3)H(6)/C(2)H(4) separation efficiency are improved. Eventually, the fluoro- and methyl-functionalized iso-MOF-4 exhibits a better gas storage and C(3)H(6)/C(2)H(4) separation performance compared with iso-MOF-1 (nonfunctionalized), iso-MOF-2 (fluoro-functionalized), and iso-MOF-3 (methyl-functionalized). A record-high C(3)H(6) uptake of 293.6 ± 2.3 cm(3) g(–1) (273 K, 1 atm) is achieved using iso-MOF-4. Moreover, iso-MOF-4 shows excellent repeatability, and only 3.5% of C(3)H(6) storage capacities decrease after nine cycles. Employing Grand Canonical Monte Carlo (GCMC) simulations, it is indicated that iso-MOF-4 preferentially adsorbs C(3)H(6) rather than C(2)H(4) at low pressure. Single-crystal X-ray diffraction on C(3)H(6)-adsorbed iso-MOF-4 crystals precisely demonstrates the adsorption positions and arrangement of C(3)H(6) molecules in the framework, which is consistent with the theoretical simulations. Remarkably, gas sorption isotherms, molecular simulations, and breakthrough experiments comprehensively demonstrate that this unique MOF material exhibits highly efficient C(3)H(6)/C(2)H(4) separation. Additionally, iso-MOF-4 also possesses efficient separation of C(3)H(8)/CH(4) and C(2)H(6)/CH(4), indicating its promising potential in storage/separation of light hydrocarbons in industry.