New Insights into the Stability of Anhydrous 2H-Imidazolium Fluoride and its High Dissolution Capability toward a Strongly Hydrogen-Bonded Compound
New Insights into the Stability of Anhydrous 2H-Imidazolium Fluoride and its High Dissolution Capability toward a Strongly Hydrogen-Bonded Compound
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DOI：
10.1021/jacs.0c04160
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发表时间：
2020-06-10
影响因子：
15
通讯作者：
Zeng, Xiao Cheng
中科院分区：
文献类型：
--
作者：
Huang, Huisheng;Zhong, Jie;Zeng, Xiao Cheng
氟化物广泛应用于医药、材料科学和精细化工领域。然而，氟化物的性能会受到水含量的显著影响。一个先前的研究（Maiti，A.;等人，Phys.Chem.Chem.Phys.2008，10，5050）提出无水1，3-二甲基咪唑鎓氟化物（[DMIm]F）是不稳定的，因为氟化物经历自分解反应。在这里，我们首先显示量子化学计算的证据，虽然气相[DMIm]F是不稳定的，无水[DMIm]F的体相是相当稳定的。然后，我们证明了通过碘化1，3-二甲基咪唑鎓和氟化银之间的反应成功合成无水[DMIm]F化合物。重要的是，我们发现无水[DMIm]F对1，3，5-三氨基-2，4，6-三硝基苯（TATB）具有高溶解能力，尽管已知TATB几乎不溶于许多常见的有机溶剂。我们的Born-Oppenheimer分子动力学（BOMD）模拟进一步表明，无水[DMIm]F对TATB的高溶解能力可以归因于F-阴离子与TATB分子之间的化学反应，这破坏了TATB分子之间的强氢键相互作用。或者，含水[DMIm]F中的水分子倾向于在F-阴离子周围形成水合层，从而防止F-与TATB分子反应。这一结果解释了为什么TATB几乎不溶于含水[DMIm]F。
Fluorides have been widely applied in pharmaceutical, medicinal, and materials science as well as in fine chemical manufacturing. The performance of fluorides, however, can be markedly affected by the water content. One previous study (Maiti, A.; et al. Phys. Chem. Chem. Phys. 2008, 10, 5050) suggested that anhydrous 1,3-dimethylimidazolium fluoride ([DMIm]F) was unstable since the fluoride undergoes a self-decomposition reaction. Herein we first show quantum-chemical calculation evidence that although gas-phase [DMIm]F is unstable, the bulk phase of anhydrous [DMIm]F is quite stable. We then demonstrate the successful synthesis of the anhydrous [DMIm]F compound via the reaction between 1,3-dimethylimidazolium iodide and silver fluoride. Importantly, we find that anhydrous [DMIm]F possesses a high dissolution capability toward 1,3,5-triamino-2,4,6-trinitrobenzene (TATB), although it is known that TATB is hardly dissolved in many common organic solvents. Our Born-Oppenheimer molecular dynamics (BOMD) simulations further show that the high dissolving ability of anhydrous [DMIm]F toward TATB can be attributed to the chemical reaction between the F- anion and the TATB molecules, which disrupts the strong hydrogen-bonding interaction among the TATB molecules. Alternatively, water molecules in hydrous [DMIm]F tend to form a hydration layer around the F- anion, thereby preventing F- from reacting with the TATB molecule. This result explains why TATB is barely dissolved in hydrous [DMIm]F.