Ren Meiyu, Zhao Bo, Li Chong, Fei Yang, Wang Xiaotong, Fan Liming, Hu Tuoping, Zhang Xiutang
School of Chemistry and Chemical Engineering, North University of China, Taiyuan, 030051, People's Republic of China.
Mol Divers. 2025 Jun;29(3):2017-2031. doi: 10.1007/s11030-024-10956-z. Epub 2024 Aug 14.
In order to achieve the high adsorption and catalytic performance of CO, the direct self-assembly of robust defect-engineered MOFs is a scarcely reported and challenging proposition. Herein, a highly robust nanoporous indium(III)-organic framework of {In(CPPDA)(HO)·2DMF·3HO} (NUC-107) consisting of two kinds of inorganic units of chain-shaped [In(COO)(HO)] and watery binuclear [In(COO)(HO)] was generated by regulating the growth environment. It is worth mentioning that [In(COO)(HO)] is very rare in terms of its richer associated water molecules, implying that defect-enriched metal ions in the activated host framework can serve as strong Lewis acid. Compared to reported skeleton of [In(CPPDA)(μ-OH)(DMF)(HO)] (NUC-66) with tetranuclear clusters of [In(μ-OH)(COO)(DMF)(HO)] as nodes, the void volume of NUC-107 (50.7%) is slightly lower than the one of NUC-66 (52.8%). However, each In ion in NUC-107 has an average of 1.5 coordinated small molecules (HO), which far exceeds the average of 0.75 in NUC-66 (HO and DMF). After thermal activation, NUC-107a characterizes the merits of unsaturated In sites, free pyridine moieties, solvent-free nanochannels (10.2 × 15.7 Å). Adsorption tests prove that the host framework of NUC-107a has a higher CO adsorption (113.2 cm/g at 273 K and 64.8 cm/g at 298 K) than NUC-66 (91.2 cm/g at 273 K and 53.0 cm/g at 298 K). Catalytic experiments confirmed that activated NUC-107a with the aid of n-BuNBr was capable of efficiently catalyzing the cycloaddition of CO with epoxides into corresponding cyclic carbonates under the mild conditions. Under the similar conditions of 0.10 mol% MOFs, 0.5 mol% n-BuNBr, 0.5 MP CO, 60 °C and 3 h, compared with NUC-66a, the conversion of SO to SC catalyzed by NUC-107a increased by 21%. Hence, this work offers a valuable perspective that the in situ creation of robust defect-engineered MOFs can be realized by regulating the growth environment.
为了实现对CO的高吸附和催化性能，通过调控生长环境直接自组装具有坚固缺陷工程的金属有机框架（MOF）是一个鲜有报道且具有挑战性的课题。在此，通过调控生长环境生成了一种高度坚固的纳米多孔铟（III）有机框架{In(CPPDA)(H₂O)·2DMF·3H₂O}（NUC - 107），它由链状[In(COO)(H₂O)]和含水双核[In(COO)₂(H₂O)]两种无机单元组成。值得一提的是，[In(COO)(H₂O)]因其富含更多的缔合水分子而非常罕见，这意味着活化主体框架中富含缺陷的金属离子可作为强路易斯酸。与报道的以四核簇[In(μ - OH)(COO)₂(DMF)(H₂O)]为节点的[In(CPPDA)(μ - OH)(DMF)(H₂O)]（NUC - 66）骨架相比，NUC - 107的孔隙率（50.7%）略低于NUC - 66（52.8%）。然而，NUC - 107中每个铟离子平均有1.5个配位小分子（H₂O），这远远超过了NUC - 66中平均0.75个（H₂O和DMF）。热活化后，NUC - 107a具有不饱和铟位点、游离吡啶基团、无溶剂纳米通道（10.2 Å×15.7 Å）等优点。吸附测试证明，NUC - 107a的主体框架对CO的吸附量（273 K时为113.2 cm³/g，298 K时为64.8 cm³/g）高于NUC - 66（273 K时为91.2 cm³/g，298 K时为53.0 cm³/g）。催化实验证实，在正丁基溴化铵的辅助下，活化后的NUC - 107a能够在温和条件下有效地催化CO与环氧化物环加成生成相应的环状碳酸酯。在0.10 mol% MOF、0.5 mol%正丁基溴化铵、0.5 MPa CO、60 °C和3 h的相似条件下，与NUC - 66a相比，NUC - 107a催化SO转化为SC的转化率提高了21%。因此，这项工作提供了一个有价值的观点，即通过调控生长环境可以实现原位创建具有坚固缺陷工程的MOF。
