A cage-based metal-organic framework with a unique tetrahedral node for size-selective CO2 capture

Due to their intriguing architectures as well as diversified functionalities and properties, cage-based metal-organic frameworks (MOFs) are urgently demanded but are more challenging and scarce. A novel three-dimensional cage-based copper-organic framework [Cu4(μ4-SO4)(tpt)4]·[SO4] (1) (tpt ​= ​2,4,6-tri(4-pyridinyl)-1,3,5-triazine) has been obtained through the assemble of rare [Cu4(μ4-SO4)] tetrahedral units and tpt ligands under solvothermal reaction condition. Compound 1 consists of two types of polyhedral cages with face-sharing configurations, and possesses a rare (3,12)-connected ttt topology. Moreover, the gas adsorption behavior investigation indicates that the activated 1a shows a high CO2 selective adsorption toward N2.