| 配位竞争策略制备的两个镁基金属有机骨架及其选择性CO2捕集 |
| Syntheses of two Mg-based metal-organic frameworks by a coordination competitive strategy and the selective CO2 capture |
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| 摘要: 利用配位竞争策略制备了2个镁基金属有机骨架(MOFs)。在酸性条件下，镁离子与N，N-二甲基甲酰胺(DMF)热分解产生的甲酸原位反应得到三维甲酸镁MOF：[Mg3(HCO2)6]·DMF (1)。在相同条件下，当加入竞争配体1，1'∶3'，1″-三联苯-3，3″，5，5″-四甲酸(H4L)后，甲酸不再参与配位，得到新的三维镁基MOF：[Mg2(L)(H2O)3]·2H2O·2CH3CN·DMF (2)。单晶X射线分析表明，MOF 1具有[Mg4@Mg2]四面体建筑块，它们形成dia拓扑网络并有一个孔径为0.44 nm的一维孔道。而MOF 2具有独特的[Mg2]双核簇，与4-连接配体L4-配位后，形成sra拓扑网络且沿a轴方向存在一个哑铃型孔道，长度为1.42 nm。气体吸附研究发现1具有微孔结构，其表面积为342 m2·g-1，但2不能保持原有多孔特征。此外，1具有良好的水稳定性且在低压下展现快速吸收的Ⅰ型CO2吸附等温线，在298 K和2 000 kPa下吸附量达到样品重量的14.5%。理想吸附溶液理论和吸附热计算表明1具有良好的选择性CO2/CH4捕获能力。 |
| 关键词: 竞争配位 镁基金属有机骨架 晶体结构 选择性CO2捕集 |
| 基金项目: 国家自然科学基金(No.21476115)和南京大学配位化学国家重点实验室开放课题资助。 |
| Abstract: Two Mg-based metal-organic frameworks (MOFs) were prepared using a coordination competition strategy. Under acidic conditions, the reaction of Mg(Ⅱ) ions with formic acid generated from the thermal decomposition of N,N-dimethylformamide (DMF) formed a 3D formate Mg-MOF: [Mg3(HCO2)6]·DMF (1). However, under the same conditions but with a competing ligand 1,1'∶3',1″-terphenyl-3,3″,5,5″-tetracarboxylic acid (H4L), formic acid was no longer involved in the coordination, resulting in a new 3D Mg-MOF: [Mg2(L) (H2O)3] ·2H2O·2CH3CN·DMF (2). Single-crystal X-ray analysis revealed that 1 possesses [Mg4@Mg2] tetrahedral building units that form a dia topological network with a 1D channel size of 0.44 nm. In contrast, 2 has a unique [Mg2] binuclear cluster to build a sra topology network after bridging the 4-connected L4- linker. Interestingly, a dumbbell-shaped pore with a length of 1.42 nm is observed along the a-axis in 2. Gas adsorption studies reveal that 1 had a significantly accessible inner surface with a surface area of 342 m2·g-1. However, after solvent removal, 2 could not retain the original porous character. Featuring good water stability, 1 exhibited a type-Ⅰ CO2 adsorption isotherm with quick uptake at low pressure, and up to 14.5% of the sample weight at 298 K and 2 000 kPa. Ideal adsorption solution theory (IAST) and adsorption heat calculations show that 1 has a good ability for selective CO2 capture from CH4 contained mixture. |
| Keywords: competitive coordination Mg-based metal-organic frameworks crystal structure selective CO2 capture |
| 投稿时间：2022-08-20 修订日期：2022-10-06 |
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| 董雨奥,冯哲,朱敦如.配位竞争策略制备的两个镁基金属有机骨架及其选择性CO2捕集[J].无机化学学报,2023,39(1):181-190. |
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