Like-charge attraction in Ionic Liquids: The influence of pressure, polarity and molecular mimics

离子液体中的同电荷吸引力：压力、极性和分子模拟的影响

• 批准号: 286149019
• 负责人: Professor Dr. Ralf Ludwig
• 金额: --
• 依托单位: Lehrstuhl für Allgemeine Physikalische und Theoretische Chemie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2016
• 资助国家: 德国
• 起止时间: 2015-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/286149019?language=en
• 关键词: Like; charge; attraction; Ionic; Liquids

In the first funding period, we showed that the interaction strength of the anion, the polarizability of the cation, and the length of hydroxy alkyl groups of the cation control the delicate balance between hydrogen-bonded cation-anion and cation-cation clusters in bulk ionic liquids. We investigated the kinetic and thermodynamic stabilities of clusters of like-charged ions. In collaboration with the Johnson group at Yale University, we started initial gas phase experiments, showing cationic complexes with cooperative hydrogen bonding between the cations despite the strong repulsive forces between them. The experimental results also shed light onto the discussion about the stability of so-called “Anti electrostatic hydrogen bonds”. The plethora of exciting results about the attractive interaction between ions of like charge provokes further questions, which we want to address in the renewal proposal: How sensitive is the cationic cluster formation to pressure? Can we control the delicate balance between cation-anion ion-pairs and the cation-cation clusters by changing the dielectric medium using solvents of different polarity? How important are specific interactions with solvent molecules? Can we enhance hydrogen bonding and cluster formation by replacing the cations by their molecular mimics? Here, the smooth transfer from ionic to molecular clusters is studied. In collaboration with the Johnson group, we also plan to investigate whether the structural motifs of cationic and molecular gas phase clusters are also present in the bulk liquid phase. We will tackle these challenges with a suitable combination of synthesis of well-selected ionic liquids, bulk and gas phase infrared spectroscopy, and quantum chemical methods.

在第一个资助期间，我们表明阴离子的相互作用强度、阳离子的极化率和阳离子的羟烷基长度控制着氢键阳离子-阴离子和阳离子-阳离子簇之间的微妙平衡。我们与耶鲁大学的约翰逊小组合作研究了带同电荷的离子簇的动力学和热力学稳定性，开始了初步的气相实验，显示了具有协同氢键的阳离子配合物。尽管阳离子之间存在很强的排斥力，但实验结果也揭示了有关所谓“反静电氢键”稳定性的讨论。关于同电荷离子之间的吸引力相互作用的大量令人兴奋的结果进一步激发了人们的兴趣。我们想在更新提案中解决的问题是：阳离子簇的形成对压力有多敏感？我们能否通过改变介电介质来控制阳离子-阴离子离子对和阳离子-阳离子簇之间的微妙平衡？不同极性的溶剂？与溶剂分子的特异性相互作用有多重要？我们可以通过用分子模拟物取代阳离子来增强氢键和簇的形成吗？在这里，与约翰逊小组合作研究了从离子到分子簇的平滑转移。我们还计划研究阳离子和分子气相簇的结构基序是否也存在于本体液相中。我们将通过精心选择的离子液体、本体和气相红外的合成的适当组合来应对这些挑战。光谱法和量子化学方法。