Cucurbituril-Shaped Cd18(triazolate)12 Unit-Based Metal-Organic Framework Exhibiting an C2H2/CO2 Separation Ability

Herein, a metal-organic framework (MOF), {[(Me2NH2)(4)][Cd(H2O)(6)][Cd-18(TrZ)(12)(TPD)(15)(DMF)(6)]}(n) (denoted as JXNU-18, TrZ = triazolate), constructed from the unique cucurbituril-shaped Cd-18(TrZ)(12) secondary building units bridged by 2,5-thiophenedicarboxylic (TPD2-) ligands, is presented. The formation of the cucurbituril-shaped Cd-18(TrZ)(12) unit is unprecedented, demonstrating the geometric compatibility of the organic linkers and the coordination configurations of the cadmium atoms. Each Cd-18(TrZ)(12) unit is connected to eight neighboring Cd-18(TrZ)(12) units through 30 TPD2- linkers, affording the three-dimensional structure of JXNU-18. More interesting is that JXNU-18 displays an efficient C2H2/CO2 separation ability, as revealed by the gas adsorption experiments and dynamic gas breakthrough experiments, which afford insights into the potential applications of JXNU-18 in gas separation. The tubular pores composed of two Cd-18(TrZ)(12) units bridged by six 2,5-thiophenedicarboxylic linkers provide the suitable pore space for C2H2 trapping, as unveiled by computational simulations.