RUI: Microsolvation and halogen substitution effects in weakly bound complexes and carbocations

RUI：弱结合络合物和碳阳离子中的微溶剂化和卤素取代效应

• 批准号: 1664900
• 负责人: Robert Chesnut
• 金额: $ 22.93万
• 依托单位: Eastern Illinois University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-08-01 至 2022-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1664900&HistoricalAwards=false
• 关键词: RUI; Microsolvation; halogen; substitution; effects

In this project, funded by the Chemical Structure, Dynamics and Mechanism A (CSDM-A) program of the Chemistry Division, Professor Sean Peebles and Professor Rebecca Peebles of Eastern Illinois University are using microwave radiation and computational techniques to study how carbon dioxide (CO2) can, under certain conditions, act like a solvent in much the same manner that water can dissolve other molecules and ions. Highly compressed CO2 behaves as a fluid, and is more environmentally friendly and more versatile than many petroleum-derived solvents used in industrial processes. However, the reasons for CO2's versatility are not well understood. In the Peebles' laboratory, a single molecule of solute is isolated with one or a few CO2 solvent molecules. By probing these small clusters with microwave radiation, the arrangement of solvent molecules can be determined. Systematically varying the number of CO2 molecules builds understanding of its unique properties as a solvent. In a second related area of research, electrically charged molecules (carbocations) are generated and their structures are studied via interactions with microwave radiation. As with the CO2 clusters, this provides information about the arrangement of atoms, in this case helping answer questions about the specific steps by which atoms rearrange during a chemical reaction. Both aspects of this research also utilize computational studies to provide more information about the arrangement of electrons within the chemical structures. The results of this research may advance the use of CO2 as a solvent in important chemical processes.The project uses Fourier-transform microwave spectroscopy for investigating structures of unstable chemical species. A theme is the effect of halogen atom substitution within the chemical structures studied. In CO2 microsolvation studies, clusters are generated using a supersonic expansion into a vacuum chamber. Examination of clusters with varying amounts of fluorine substitution builds towards an understanding of why fluorinated species have unusually high solubility in supercritical CO2. Varying the number of CO2 molecules in a cluster allows observation of how weak intermolecular interactions vary as solvation occurs. The knowledge gained from these studies may also help in understanding and building CO2 sequestration frameworks using custom designed molecules. In the second part of the research, carbocations are generated using a pulsed discharge nozzle or electron gun together with the supersonic expansion. Probing with microwave radiation then provides structural information, helping scientists to understand whether carbocations exist in cyclic or noncyclic forms, and how structures change as halogen substitution is varied. In addition to implications for industrial use of CO2, broader impacts are hands-on education of undergraduate students in Chemistry and other STEM fields. Students gain significant practical, problem solving and computer skills and improve their critical thinking abilities.

In this project, funded by the Chemical Structure, Dynamics and Mechanism A (CSDM-A) program of the Chemistry Division, Professor Sean Peebles and Professor Rebecca Peebles of Eastern Illinois University are using microwave radiation and computational techniques to study how carbon dioxide (CO2) can, under certain conditions, act like a solvent in much the same manner that water can dissolve other molecules and ions. 高度压缩的二氧化碳表现为流体，并且比许多石油衍生的溶剂更环保，更通用。 但是，二氧化碳多功能性的原因尚不清楚。在Peebles的实验室中，用一个或几个二氧化碳溶剂分子分离出单个溶质分子。通过用微波辐射探测这些小簇，可以确定溶剂分子的排列。系统地改变了二氧化碳分子的数量，从而建立了对其独特特性作为溶剂的理解。在第二个相关的研究领域中，产生了电荷分子（碳化物），并通过与微波辐射的相互作用来研究其结构。与二氧化碳簇一样，这提供了有关原子排列的信息，在这种情况下，有助于回答有关化学反应过程中原子重新排列的特定步骤的问题。这项研究的两个方面还利用计算研究来提供有关化学结构中电子布置的更多信息。 这项研究的结果可能会推动将CO2用作重要化学过程中的溶剂。该项目使用傅立叶转换微波光谱来研究不稳定化学物种的结构。一个主题是所研究的化学结构中卤素原子取代的效果。在CO2微覆盖研究中，使用超音速扩张到真空室中产生簇。检查具有不同数量的氟取代的簇的检查，以了解为什么氟化物种在超临界二氧化碳中具有异常高的溶解度。簇中二氧化碳分子的数量变化，可以观察到弱分子间相互作用如何随着溶剂化的发生而变化。从这些研究中获得的知识也可能有助于使用自定义设计的分子理解和构建CO2封存框架。在研究的第二部分中，使用脉冲排放喷嘴或电子枪以及超音速膨胀产生碳水化化。然后，用微波辐射进行探测，然后提供结构信息，帮助科学家了解是否以环状或非循环形式存在碳水化合物，以及随着卤素替代的变化，结构如何变化。除了对二氧化碳的工业使用的影响外，更广泛的影响还对化学和其他STEM领域的本科生进行了动手教育。学生可以获得大量实用，解决问题和计算机技能，并提高其批判性思维能力。

项目成果

Spectroscopic models of CO2 microsolvation: Bringing data analytics techniques to undergraduate physical chemistry research

CO2 微溶剂化的光谱模型：将数据分析技术引入本科生物理化学研究

• 发表时间: 2021
• 期刊: American Chemical Society National Meeting Fall 2021
• 作者: Peebles, Rebecca A.;Peebles, Sean A.;Kannangara, Prashansa B.;Fino, Hannah L.;Martinez, Melissa A.;Ariyaratne, Tulana
• 通讯作者: Ariyaratne, Tulana

Investigation of a polar form of fluoroethylene dimer, (C2H3F)2, by microwave spectroscopy

通过微波光谱研究极性形式的氟乙烯二聚体 (C2H3F)2

• DOI: 10.1016/j.molstruc.2020.128038
• 发表时间: 2020
• 期刊: Journal of Molecular Structure
• 影响因子: 3.8
• 作者: Martinez, Melissa A.;West, Channing T.;Pate, Brooks H.;Peebles, Sean A.;Peebles, Rebecca A.
• 通讯作者: Peebles, Rebecca A.

Microwave Spectra and Structure of Ar–1,3-Difluorobenzene

Ar-1,3-二氟苯的微波光谱和结构

• DOI: 10.1021/acs.jpca.8b05282
• 发表时间: 2018
• 期刊: The Journal of Physical Chemistry A
• 作者: Marshall, Frank E.;Dorris, Rachel;Peebles, Sean A.;Peebles, Rebecca A.;Grubbs, G. S.
• 通讯作者: Grubbs, G. S.

Towards and understanding of CO2 microsolvation: Microwave spectroscopy of CO2 complexes with fluoroethylenes

CO2 微溶剂化的走向和理解：CO2 与氟乙烯络合物的微波光谱

• 发表时间: 2017
• 期刊: 254th American Chemical Society National Meeting
• 作者: Peebles, Rebecca A.;Peebles, Sean A.;Anderton, Ashley M.;Christenholz, Cori L.;Dorris, Rachel E.;Trendell, William C.
• 通讯作者: Trendell, William C.

σ–Hole activation and structural changes upon perfluorination of aryl halides: direct evidence from gas phase rotational spectroscopy

芳基卤化物全氟化时的空穴活化和结构变化：来自气相旋转光谱的直接证据

• DOI: 10.1039/d1cp03023j
• 发表时间: 2021
• 期刊: Physical Chemistry Chemical Physics
• 影响因子: 3.3
• 作者: Lv, Dingding;Maris, Assimo;Evangelisti, Luca;Maggio, Andrea;Song, Wentao;Elliott, Ashley A.;Peebles, Sean A.;Neill, Justin L.;Muckle, Matt T.;Pate, Brooks H.
• 通讯作者: Pate, Brooks H.