In this work, three porous MOFs (ZJNU-74, ZJNU-75 and ZJNU-76) were constructed via solvothermal reactions of unsymmetrical naphthalene-derived diisophthalate ligands and Cu²⁺ ions. As revealed by single-crystal X-ray diffraction analyses, they consist of dicopper [Cu₂(COO)₄] paddlewheels connected by the organic ligands to form three-dimensional networks with the same ssa topology, thus representing a MOF platform which allows understanding of the structure–property relationship. The gas adsorption properties of the three MOF compounds with respect to C₂H₂, CO₂ and CH₄ have been systematically investigated. They exhibit very high C₂H₂ uptakes varying from 179.2 to 188.6 cm³ (STP) g⁻¹ and CO₂ uptakes varying from 88.1 to 99.2 cm³ (STP) g⁻¹ at 298 K and 1 atm. The predicted IAST selectivities range from 24.9 to 29.7 for an equimolar C₂H₂/CH₄ gas mixture and from 4.8 to 5.4 for an equimolar CO₂/CH₄ gas mixture at 298 K and 1 atm. These results reveal that they possess very promising potential for C₂H₂/CH₄ and CO₂/CH₄ separations. In particular, compared to the unmodified parent MOF ZJNU-74, the alkoxy group-functionalized MOFs ZJNU-75 and ZJNU-76 exhibit comparable and even higher C₂H₂ and CO₂ uptake capacities as well as better C₂H₂/CH₄ and CO₂/CH₄ adsorption selectivities under ambient conditions, which might be attributed to the optimized pore sizes as a result of ligand modification.

中文翻译：

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由不对称二间苯二甲酸酯构成的ssa型铜基MOF家族：合成，表征和选择性气体吸附

在这项工作中，通过不对称萘衍生的二间苯二甲酸邻苯二甲酸酯配体和Cu ²⁺离子的溶剂热反应，构建了三个多孔MOF（ZJNU-74，ZJNU-75和ZJNU-76）。正如单晶X射线衍射分析所揭示的那样，它们由有机配体连接的双铜[Cu ₂（COO）₄ ]桨轮组成，形成具有相同ssa拓扑的三维网络，因此代表了一个MOF平台，可以理解结构-财产关系。三种MOF化合物对C ₂ H ₂，CO ₂的气体吸附特性CH ₄和CH ₄已被系统地研究。它们在298 K和1个大气压下表现出非常高的C ₂ H ₂吸收量，变化范围从179.2至188.6 cm ³（STP）g ^-1，而CO ₂吸收量从88.1至99.2 cm ³（STP）g ^-1变化。对于等摩尔的C ₂ H ₂ / CH ₄气体混合物，在298 K和1 atm的等摩尔CO ₂ / CH ₄气体混合物，预测的IAST选择性为24.9至29.7，对于等摩尔的CO ₂ / CH ₄气体混合物，预测的IAST选择性为4.8至5.4 。这些结果表明，它们具有非常有前途的C ₂ H ₂ / CH潜力。₄和CO ₂ / CH ₄分离。特别地，与未修饰的母体MOF ZJNU-74相比，烷氧基官能化的MOF ZJNU-75和ZJNU-76表现出相当甚至更高的C ₂ H ₂和CO ₂吸收能力以及更好的C ₂ H ₂ / CH ₄和在环境条件下的CO ₂ / CH ₄吸附选择性，这可能归因于配体改性带来的最佳孔径。