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, [Cd 3 (L) 2 (H 2 O) 6 ]·1.5H 2 O·2EtOH·DMF ( 1, H 3 L = 2,4,6-tris-(4-carboxyphenoxy)-1,3,5-triazine) and [Zn 3 (L) 2 (H 2 O) 2 ]·3H 2 O·TEA·2DMF ( 2 ), with single- and double-(6,3)-layer structures, respectively, have been synthesized by the reaction of Cd(Zn) nitrate with H 3 L in a mixed solvent of DMF, ethanol, and H 2 O. 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 CO 2 over CH 4 and N 2 and could adsorb considerable amounts of H 2 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 H 2 O, 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.