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.