A Microporous Heterovalent Copper–Organic Framework Based on [Cu2I]n and Cu2(CO2)4 Secondary Building Units: High Performance for CO2 Adsorption and Separation and Iodine Sorption and Release

A microporous heterovalent Cu-based MOF, [(Cu2I)Cu2L2(H2O)2]22+·2NO3–·5DMF (1) (H2L = 5-(4H-1,2,4-triazol-4-yl)benzene-1,3-dicarboxylic acid, DMF = N,N-dimethylformamide), has been successfully synthesized using the mixed secondary building unit (SBU) strategy. Compound 1 was constructed from [Cu2I]n chain and Cu2(CO2)4 paddlewheel SBUs and exhibited a new (3,4,4)-connected topology. Although compound 1 possesses moderate surface area, it exhibits better CO2 capture (91.9 cm3 g–1 at 273 K) and separation ability (selectivity for CO2 over CH4 = 8.2 under 1 bar at 298 K) than most of the reported CuxIy-based MOFs. Moreover, compound 1 is also a good candidate for the capture and release of iodine.