Probing Nanostructural Organization in the Intermolecular and Orientational Dynamics of Small Molecules in Ionic Liquids Using Optical Kerr Effect Spectroscopy

使用光学克尔效应光谱法探测离子液体中小分子的分子间和取向动力学中的纳米结构组织

• 批准号: 1153077
• 负责人: Edward Quitevis
• 金额: $ 43.84万
• 依托单位: Texas Tech University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-09-01 至 2017-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1153077&HistoricalAwards=false
• 关键词: Probing; Nanostructural; Organization; Intermolecular; Orientational

Professor Edward Quitevis of Texas Tech University is being supported by the Chemical Structure, Dynamics and Mechanism Program to study the role of nanostructural organization in determining the intermolecular and orientational dynamics of small molecules in ionic liquids (ILs). The main approach will be to use optical Kerr effect (OKE) spectroscopy to probe dynamics in molecular liquid-IL mixtures. Novel ILs will be synthesized with specific structural features that allow the local environment of the molecular solute to be varied systematically. The significance of this work is that specific interactions of the IL with functional groups on a solute molecule often underlie solute-IL interactions. In order to understand, for example, the effect of ILs on chemical reactions, it is therefore important to study the interactions of ILs with small solute molecules that mimic the functional groups on larger molecules. This research will address the following questions: (1) How are the intermolecular and orientational dynamics of nonpolar molecules in the nonpolar domains of ILs similar to or different from that of nonpolar molecules in alkane solvents? (2) Are the OKE data for mixtures of ILs and polar liquids consistent with polar solute molecules being localized at the polar-nonpolar interface? (3) What can OKE measurements on mixtures of ILs and aromatic liquids tell us about the difference between dynamics of aromatic molecules in polar domains and dynamics of aromatic molecules in nonpolar domains? The outcomes are expected to help elucidate the complex solute-solvent interactions in ILs from the perspective of nanosegregation. Although many of the physicochemical properties of ILs can be understood using standard molecular liquid concepts, there is great interest in discovering IL properties that are atypical of conventional molecular solvents. Nanoscale structural heterogeneity in ILs is one of those properties. The idea that ILs can be thought of as "2-in-1" solvents has broad implications from the standpoint of solvation of solute molecules and, ultimately, chemical reaction dynamics in ILs. The main goal of the investigator's research is to understand molecular scale organization in ILs for the purpose of using this property in basic science and technological applications. This research will provide fundamental knowledge that is critical to the rational design of task-specific ILs for current and future applications that contribute to the goal of achieving a sustainable society, such as lithium-ion batteries, biomass processing, and carbon dioxide capture. Aside from the technological benefits, the project provides strong educational training to undergraduate, graduate, and postdoctoral researchers in areas ranging from chemical synthesis to lasers and optics. In particular, the PI has developed a pilot summer undergraduate research program at Texas Tech that provides underrepresented minority students the opportunity to participate in this project.

德克萨斯理工大学的 Edward Quitevis 教授正在化学结构、动力学和机制计划的支持下，研究纳米结构组织在确定离子液体 (IL) 中小分子的分子间和取向动力学中的作用。主要方法是使用光学克尔效应 (OKE) 光谱来探测分子液体-IL 混合物中的动力学。新型离子液体将被合成为具有特定的结构特征，使分子溶质的局部环境能够系统地变化。这项工作的意义在于，IL 与溶质分子上官能团的特定相互作用通常是溶质-IL 相互作用的基础。例如，为了了解 IL 对化学反应的影响，研究 IL 与模拟大分子官能团的小溶质分子的相互作用非常重要。本研究将解决以下问题：（1）离子液体非极性域中的非极性分子的分子间和取向动力学与烷烃溶剂中的非极性分子有何相似或不同？ (2) 离子液体和极性液体混合物的 OKE 数据是否与极性溶质分子位于极性-非极性界面一致？ (3) 离子液体和芳香液体混合物的 OKE 测量可以告诉我们极性域中芳香族分子动力学与非极性域中芳香族分子动力学之间的差异吗？研究结果预计将有助于从纳米偏析的角度阐明离子液体中复杂的溶质-溶剂相互作用。尽管使用标准分子液体概念可以理解离子液体的许多物理化学性质，但人们对发现传统分子溶剂非典型的离子液体性质非常感兴趣。 IL 的纳米级结构异质性就是其中之一。从溶质分子溶剂化以及最终的离子液体化学反应动力学的角度来看，离子液体可以被视为“二合一”溶剂，这一想法具有广泛的意义。研究人员研究的主要目标是了解离子液体中的分子尺度组织，以便在基础科学和技术应用中利用这一特性。这项研究将为当前和未来应用的特定任务IL的合理设计提供至关重要的基础知识，这些应用有助于实现可持续社会的目标，例如锂离子电池、生物质加工和二氧化碳捕获。除了技术优势外，该项目还为化学合成、激光和光学等领域的本科生、研究生和博士后研究人员提供了强有力的教育培训。特别是，PI 在德克萨斯理工大学开发了一个试点夏季本科研究项目，为代表性不足的少数族裔学生提供参与该项目的机会。