Two heterovalent copper–organic frameworks with multiple secondary building units: high performance for gas adsorption and separation and I2 sorption and release†
With the help of the multiple secondary building unit (SBU) strategy, two novel heterovalent Cu–MOFs, [(Cu4I4)Cu4L4(DABCO)2]·16DMF (JLU-Liu31) and [(Cu4I4)Cu3L3(DABCO)(DMF)2]·18DMF (JLU-Liu32) [H2L = pyridine-3,5-bis(phenyl-4-carboxylic acid), DABCO = 1,4-diazabicyclo[2.2.2]-octane], have been successfully solvothermally synthesized and structurally characterized. Both of the two compounds feature multiple SBUs and exhibit novel topologies. JLU-Liu31 possesses the largest sustainable pore volume among the MOFs based on Cu4I4 clusters. Moreover, the adsorption behaviours of the desolvated JLU-Liu31 material for some small gases (H2, O2, CO2, CH4, C2H6 and C3H8) have been analysed in low pressure regions; meanwhile, it exhibits commendable selectivity for O2 over N2, and C3H8 over CH4. The remarkable results illustrate that JLU-Liu31 is a good candidate for application in the separation of light hydrocarbons. Additionally, JLU-Liu32 exhibits impressive performance for I2 sorption and release in solvents.