Two copper-based MOFs constructed from a linear diisophthalate linker: supramolecular isomerism and gas adsorption properties

摘要

Combining a linear diisophthalate ligand, 5,5'-(2,3-dimethylbenzene-1,4-diyl) diisophthalic acid, with CuCl2 center dot 2H(2)O under different solvothermal conditions afforded two distinct copper-based metal-organic frameworks (ZJNU-96 and ZJNU-97), which were structurally characterized by various techniques. Single-crystal X-ray diffraction analyses reveal that they contain the same inorganic and organic building units but exhibit different topological structures, thus belonging to supramolecular isomers. Furthermore, gas adsorption studies show that ZJNU-96 not only exhibits better stability against desolvation than ZJNU-97 but also displays promising potential for selective adsorptive separation of C2H2 and CO2 from CH4, with C2H2 (CO2) uptake of 183.6 (88.7) cm(3) (STP) g(-1) and C2H2 (CO2)/CH4 (v/v, 50/50) IAST adsorption selectivity of 26.6 (5.2) at 298 K and 1 atm.