Three Metal–Organic Frameworks Based on Binodal Inorganic Building Units and Hetero-O, N Donor Ligand: Solvothermal Syntheses, Structures, and Gas Sorption Properties

Three new metal–organic frameworks (MOFs) based on hetero-O, N donor ligands, (Cu4I4)­[Cu2(PDC)2­DMF2]2·2DMF·H2O (JLU-Liu15), (Cu4I4)­[Cu3(CPNA)3­(Dabco)0.5­DMF3]·4DMF·4H2O (JLU-Liu16), and (Cu4I4)­[Cu3(CPNA)3­(H2O)0.5­DMF3]·4DMF·4H2O (JLU-Liu17), (H2PDC = pyridine-3,5-dicarboxylic acid, H2CPNA = 5-(4′-carboxylphenyl) nicotinic acid, Dabco = 1,4-diazabicyclo­[2.2.2]­octane), have been solvothermally synthesized and structurally characterized by single-crystal X-ray diffraction analyses. JLU-Liu15 features a (3,4,4)-c sqc5588 net, whereas JLU-Liu16 and JLU-Liu17 are isostructural and possess a new (3,4,4)-c topology. All of these compounds are composed of the binodal inorganic Cu2(CO2)4 paddlewheel and Cu4I4 cluster secondary building units (SBUs). It is worthy to note that the linkage between two nearby Cu4I4 clusters in JLU-Liu16 is μ2-Dabco, which changed to a μ2-water molecule in JLU-Liu17. Furthermore, JLU-Liu15 exhibits high CO2 adsorption behaviors as well as I2 uptake and release features.