New Zn-Aminotriazolate-Dicarboxylate Frameworks: Synthesis, Structures, and Adsorption Properties

Three Zn-triazolate-dicarboxylate frameworks, namely, [Zn2(atz)2(ipa)] (1, Hatz = 3-amino-1,2,4-triazole, H2ipa = isophthalic acid), [Zn2(datz)2(ipa)] (2, Hdatz = 3,5-diamino-1,2,4-triazole), and [Zn2(atz)2(oba)] (3, H2oba = 4,4′-oxobisbenzoic acid), have been synthesized by solvothermal reactions. Crystal-structure analyses demonstrated that 1–3 are isoreticular three-dimensional porous structures consisting of Zn-triazolate layers and dicarboxylate pillars. The major differences of three compounds are the lengths and orientations of the pillars. Thermogravimetry analyses and powder X-ray diffraction measurements showed that 1–3 have high thermal stability and good water stability. The adsorption properties of 1–3 were investigated by N2, CO2, and CH4 sorption experiments. Because 3 has exposed amino groups and distinct pore shape, it has the highest CO2 uptake and CO2/N2 and CO2/CH4 selectivities at 273 K.