Das Rajesh, Nagaraja C M
Department of Chemistry, Indian Institute of Technology Ropar, Rupnagar 140001, Punjab, India.
Inorg Chem. 2020 Jul 20;59(14):9765-9773. doi: 10.1021/acs.inorgchem.0c00987. Epub 2020 Jul 6.
The rapid increase in the concentration of atmospheric carbon dioxide (CO) has resulted in undesirable environmental issues. Hence, selective CO capture and utilization as C1 feedstock for the preparation of high-value chemicals and fuels has been considered as a promising step toward mitigating the growing concentration of atmospheric CO. In this direction, herein we report rational construction of a Ag(I)-anchored sulfonate-functionalized UiO-66 MOF named as MOF-SOAg composed of CO-philic sulfonate functionality and catalytically active alkynophilic Ag(I) sites for chemical fixation of carbon dioxide. The MOF-SOAg exhibits selective as well as recyclable adsorption of CO with a high heat of adsorption energy () of 37.8 kJ/mol. On the other hand, the analogous MOF, UiO-66 doped with Ag(I), showed a lower value of 30 kJ/mol, highlighting the importance of the sulfonate group for stronger interaction with CO. Furthermore, the MOF-SOAg acts as an efficient heterogeneous catalyst for cyclic carboxylation of propargylic alcohols to generate α-alkylidene cyclic carbonates in >99% yield at mild conditions of RT and 1 bar CO. More importantly, one-pot synthesis of oxazolidinones by a three-component reaction between CO, propargylic alcohol, and primary amine has also been achieved using MOF-SOAg catalyst under the mild conditions. The MOF is highly recyclable and retains its superior catalytic activity even after several cycles. To the best of our knowledge, MOF-SOAg is the first example of MOF reported for RT chemical fixation of CO to oxazolidinones by aminolysis of α-alkylidene cyclic carbonates under the environment-friendly mild conditions.
大气中二氧化碳（CO₂）浓度的迅速增加已导致不良的环境问题。因此，选择性捕获和利用CO₂作为制备高价值化学品和燃料的C1原料，被认为是朝着缓解大气中不断增加的CO₂浓度迈出的有希望的一步。在这个方向上，我们在此报告了一种合理构建的Ag(I)锚定的磺酸盐功能化UiO-66金属有机框架，命名为MOF-SOAg，它由亲CO₂的磺酸盐官能团和催化活性的亲炔基Ag(I)位点组成，用于二氧化碳的化学固定。MOF-SOAg表现出对CO₂的选择性以及可回收吸附，其吸附热（ΔH）高达37.8 kJ/mol。另一方面，类似的掺杂Ag(I)的MOF，UiO-66，显示出较低的ΔH值为30 kJ/mol，突出了磺酸盐基团对于与CO₂更强相互作用的重要性。此外，MOF-SOAg在室温（RT）和1 bar CO₂的温和条件下，作为一种高效的非均相催化剂，用于炔丙醇的环羧化反应，以>99%的产率生成α-亚烷基环状碳酸酯。更重要的是，并使用MOF-SOAg催化剂在温和条件下，通过CO₂、炔丙醇和伯胺之间的三组分反应，也实现了恶唑烷酮的一锅合成。该MOF具有高度可回收性，即使经过几个循环也能保持其优异的催化活性。据我们所知，MOF-SOAg是报道的首例在环境友好的温和条件下，通过α-亚烷基环状碳酸酯的氨解将CO₂在室温下化学固定为恶唑烷酮的MOF实例。
