Two stable 3D porous metal–organic frameworks with high performance for gas adsorption and separation†
Two porous MOFs, [NO3][In3OL3]·4DMF·3H2O (JLU-Liu18) and [CdL]·0.5DMF (JLU-Liu19), H2L = pyridine-3,5-bis(phenyl-4-carboxylic acid), have been solvothermally synthesized and structurally characterized. Both of the two compounds possess a saturated coordination metal centre without open metal sites (OMSs) leading to remarkable thermal and water vapour stability. JLU-Liu18 displays a rare occurrence of 9-connected, trinuclear [In3O(CO2)6N3] secondary building units (SBUs) in a porous crystal, with high adsorption for small gases, especially CO2 (129 and 400 cm3 g−1 at 273 and 195 K, respectively, under 1 bar). It also performs with commendable selectivity for O2 over N2, and CO2, C2H6, C3H8 over CH4. JLU-Liu19 possesses outstanding performance for sieving small gases owing to its ultramicropores of 3.5 Å. Both of the two MOFs are promising materials for gas adsorption and purification.