Organic Cation Templated Synthesis of Three Zinc–2,5-Thiophenedicarboxylate Frameworks for Selective Gas Sorption

Three anionic Zn­(II)–organic frameworks with 2,5-thiophenedicarboxylate ligand have been synthesized solvothermally. They exhibit different 3D net topologies but all contain trinuclear [Zn3(COO)8] building units. Compound 1 shows an 8-connected bcg net just based on [Zn3(COO)8] nodes, while compound 2 displays an 8-connected bcu net based on two similar [Zn3(COO)8] nodes. Interestingly, compound 3 represents a novel (4,8)-connected flu net based on the trinuclear nodes [Zn3(COO)8] and the binuclear nodes [Zn2(COO)4]. Gas sorption measurements indicate that the desolvated host 1-ht exhibits permanent porosity with Langmuir surface area of 630.5 m2·g–1 and a H2 uptake of 109.5 cm3·g–1 at 77 K and 1 atm, as well as a selective sorption of CO2 over N2 at 0 °C and ambient pressure.本研究通过溶剂热法合成了三种以2,5-噻吩二羧酸（2,5-thiophenedicarboxylate）为配体的阴离子型Zn(II)金属有机框架（Zn(II)-organic frameworks）。三种框架展现出各异的三维网络拓扑结构，但均以三核[Zn3(COO)8]作为次级构筑单元。化合物1仅以[Zn3(COO)8]作为节点，展现出八连接的bcg拓扑网络；而化合物2则基于两个结构相似的[Zn3(COO)8]节点，形成八连接的bcu拓扑网络。有趣的是，化合物3以三核[Zn3(COO)8]节点与双核[Zn2(COO)4]节点为构筑基础，构建出一种新型的(4,8)-连接flu拓扑网络。气体吸附测试结果表明，脱溶剂后的主体框架1-ht具有永久孔隙结构，其朗缪尔比表面积为630.5 m²·g⁻¹，在77 K、1标准大气压下的氢气吸附量可达109.5 cm³·g⁻¹，同时在0 ℃、常压下对CO2相较于N2展现出选择性吸附性能。