Three highly porous MOFs with dinuclear [M₂(OH)_0.5(NO₃)_0.5(RCOO)₂(RN)₄] SBUs (secondary building units), [Cu₄(L₁)₄(OH)(NO₃)]·2(NO₃)·4DMF (compound Cu-L₁, HL₁ = 5-imidazol-1-yl-nicotinic acid, DMF = N,N-dimethylformamide), [Ni₄(L₁)₄(OH)(NO₃)₃(DMF)₂]·3DMF·4H₂O (compound Ni-L₁) and [Ni₄(L₂)₄(OH)(NO₃)₃(DMF)₂]·3DMF (compound Ni-L₂, HL₂ = 5-[1,2,4]triazol-1-yl-nicotinic acid), have been solvothermally constructed using a heterofunctional ligand motif with carboxylate and azolate groups. All three compounds show high thermal and chemical stability, not only in water but also in acidic and basic solutions (pH = 2–11). Due to the presence of accessible open metal sites (OMSs), compounds Cu-L₁, Ni-L₁, and Ni-L₂ exhibit significant ability to capture CO₂ (114.8, 88.3 and 93.7 cm³ g⁻¹, respectively, under 1 bar at 273 K). Interestingly, gas adsorption results show that all three compounds exhibit high selectivity toward O₂ over N₂ at 77 K and C₃H₈ over CH₄ at 298 K, which indicates that the three materials have potential for gas separation applications.

中文翻译：

---

三种稳定的双核[M2（OH）0.5（NO3）0.5（RCOO）2（RN）4]（M = Cu，Ni）基金属-有机骨架，具有高的CO2吸附能力以及对O2 / N2和C3H8 / CH4的选择性分离

具有双核[M ₂（OH）_0.5（NO ₃）_0.5（RCOO）₂（RN）₄ ] SBU（二级结构单元），[Cu ₄（L ₁）₄（OH）（NO ₃）]的三个高度多孔的MOF。·2（NO ₃）·4DMF（化合物Cu-L ₁，HL ₁ = 5-咪唑-1-基-烟酸，DMF = N，N-二甲基甲酰胺），[Ni ₄（L ₁）₄（OH）（ NO ₃）₃（DMF）₂ ]·3DMF·4H ₂O（化合物Ni-L ₁）和[Ni ₄（L ₂）₄（OH）（NO ₃）₃（DMF）₂ ]·3DMF（化合物Ni-L ₂，HL ₂ = 5- [1,2,4 [三唑-1-基-烟酸]，已使用具有羧酸根和偶氮根基团的杂功能配体基序进行溶剂热构建。这三种化合物不仅在水中而且在酸性和碱性溶液（pH = 2-11）中均显示出高的热稳定性和化学稳定性。由于存在可访问的开放金属位点（OMS），因此化合物Cu-L ₁，Ni-L ₁和Ni-L ₂表现出显着的捕获CO _2的能力（在273 K下1 bar下分别为114.8、88.3和93.7 cm ³ g ^-1）。有趣的是，气体吸附结果表明，这三种化合物对77 K的N _2的O ₂和对298 K的CH _4的C ₃ H ₈都有很高的选择性，这表明这三种材料具有用于气体分离的潜力。