Single- and Double-Layer Structures and Sorption Properties of Two Microporous Metal–Organic Frameworks with Flexible Tritopic Ligand

Two 2D multifunctional microporous
metal–organic frameworks,
[Cd3(L)2(H2O)6]·1.5H2O·2EtOH·DMF (1, H3L = 2,4,6-tris-(4-carboxyphenoxy)-1,3,5-triazine)
and [Zn3(L)2(H2O)2]·3H2O·TEA·2DMF (2), with single- and double-(6,3)-layer
structures, respectively, have been synthesized by the reaction of
Cd­(Zn) nitrate with H3L in a mixed solvent of DMF, ethanol,
and H2O. TGA and PXRD analysis showed that compounds 1 and 2 were thermally stable up to 250 °C.
Gas sorption measurement indicates that compounds 1 and 2 exhibited selective sorption capabilities for CO2 over CH4 and N2 and could adsorb considerable
amounts of H2 at low temperature. These two compounds also
showed high sorption capabilities for water, methanol, and ethanol
vapors. The highest adsorption amounts of compounds 1 and 2 are 168.8 and 257.3 cc/g for H2O,
175.1 and 140.8 cc/g for methanol, and 91.7 and 76.2 cc/g for ethanol,
respectively. Furthermore, the maximum luminescence emission peaks
of compounds 1 and 2 exhibit blue shifts
of 138 and 132 nm, respectively, compared to the free ligand.