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.本研究通过溶剂热反应（solvothermal reactions）合成了三种锌-三唑-二羧酸盐骨架材料，分别为[Zn₂(atz)₂(ipa)]（编号1，其中Hatz代表3-氨基-1,2,4-三唑(3-amino-1,2,4-triazole)，H₂ipa代表间苯二甲酸(isophthalic acid)）、[Zn₂(datz)₂(ipa)]（编号2，其中Hdatz代表3,5-二氨基-1,2,4-三唑(3,5-diamino-1,2,4-triazole)）以及[Zn₂(atz)₂(oba)]（编号3，其中H₂oba代表4,4'-氧代双苯甲酸(4,4′-oxobisbenzoic acid)）。晶体结构分析（Crystal-structure analyses）结果表明，1至3均为同构（isoreticular）三维多孔结构，由锌-三唑层与二羧酸盐支柱构成，三种化合物的主要差异在于支柱的长度与取向。热重分析（Thermogravimetry analyses）与粉末X射线衍射（powder X-ray diffraction）测试显示，1至3均具备优异的热稳定性与良好的水稳定性。本研究通过氮气（N₂）、二氧化碳（CO₂）与甲烷（CH₄）吸附实验，对1至3的吸附性能进行了探究，由于化合物3暴露有氨基基团且具有独特的孔道形貌，其在273 K下展现出最高的CO₂吸附量以及最优的CO₂/N₂与CO₂/CH₄吸附选择性。