Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
J Phys Chem B. 2012 Oct 4;116(39):11943-52. doi: 10.1021/jp303915c. Epub 2012 Sep 24.
Room-temperature ionic liquids (RTILs) are regarded as green solvents due to their low volatility, low flammability, and thermal stability. RTILs exhibit wide electrochemical windows, making them prime candidates as media for electrochemically driven reactions such as electro-catalysis and electro-plating for separations applications. Therefore, understanding the factors determining edges of the electrochemical window, the electrochemical stability of the RTILs, and the degradation products is crucial to improve the efficiency and applicability of these systems. We present here computational investigations of the electrochemical properties of a variety of RTILs covering a wide range of electrochemical windows. We proposed four different approaches with different degrees of approximation and computational cost from gas-phase calculations to full explicit solvation models. It was found that, whereas the simplest model has significant flaws in accuracy, implicit and explicit solvent models can be used to reliably predict experimental data. The general trend of electrochemical windows of the RTILs studied is well reproduced, showing that it increases in the order of imidazolium < ammonium < pyrrolidinium < phosphonium giving confidence to the methodology presented to use it in screening studies of ionic liquids.
室温离子液体（RTILs）因其低挥发性、低可燃性和热稳定性而被视为绿色溶剂。RTILs 具有较宽的电化学窗口，因此它们是电化学驱动反应（如电催化和电镀）的理想介质，可用于分离应用。因此，了解决定电化学窗口边缘、RTILs 的电化学稳定性和降解产物的因素对于提高这些系统的效率和适用性至关重要。我们在这里介绍了对涵盖广泛电化学窗口的各种 RTILs 的电化学性质的计算研究。我们提出了四种不同的方法，从气相计算到完全显式溶剂化模型，具有不同的近似程度和计算成本。结果表明，尽管最简单的模型在准确性上存在明显缺陷，但隐式和显式溶剂模型可用于可靠地预测实验数据。所研究的 RTILs 的电化学窗口的一般趋势得到了很好的再现，表明其顺序为咪唑 <铵 <吡咯烷 <膦，这为所提出的方法提供了信心，可用于筛选离子液体的研究。
