Solvent-induced framework-interpenetration isomers of Cu MOFs for efficient light hydrocarbon separation†
Abstract
By tuning interpenetrated and non-interpenetrated frameworks, a pair of Cu-paddlewheel framework-interpenetration isomers (UPC-34, [Cu3(L)2(H2O)3]·2DMF·3EtOH·3H2O and UPC-35, [Cu3(L)2(H2O)3]·2DMF·2Diox·3H2O) based on a tripodal ligand (H3L = 4,4′-((5-carboxy-1,3-phenylene)bis(ethyne-2,1-diyl))dibenzoic acid) has been synthesized and characterized. The interpenetrated framework (UPC-35) is more stable than the non-interpenetrated one (UPC-34). Due to the 2-fold interpenetration, UPC-35 has a pore size distribution of ∼4.5 Å, which is close to the kinetic diameters of light hydrocarbons (C1–C3), and thus exhibits high gas-uptake capacities for C3H6 and C3H8. Furthermore, UPC-35 is an effective adsorbent for the selective separation of C3/C2/C1 light hydrocarbons.