RUI: Shape Matters: Using the Preferred Structures of Gas-Phase Heterodimers to Investigate Intermolecular Forces and for Chiral Analysis

RUI：形状很重要：利用气相异二聚体的首选结构研究分子间力和手性分析

• 批准号: 1856637
• 负责人: Helen Leung
• 金额: $ 33.87万
• 依托单位: Amherst College
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-07-01 至 2023-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1856637&HistoricalAwards=false
• 关键词: RUI; Shape; Matters; Using; Preferred

In this project funded by the Chemical Structure Dynamics and Mechanisms (CSDM-A) program of the Chemistry Division, Professors Helen O. Leung and Mark D. Marshall of Amherst College use high speed, state-of-the-art methods to measure the microwave radiation given off by complexes formed between two individual molecules rotating together in space. The patterns of the specific frequencies emitted is analyzed to determine the detailed shape of the complex. The research gives fundamental information into how the two molecules are arranged with respect to each other along with precise distances and angles. This information, in turn, indicates the nature of the forces that molecules exert upon each other. Such forces have important consequences for many chemical and biological systems, but are difficult to separate from the larger effects of the much stronger chemical bonds. This project seeks to provide a greater understanding of intermolecular interactions. The research also use these interactions to differentiate between mirror image molecules that have identical physical properties but different biological effects. The undergraduate students engaged in this research receive valuable hands-on experience with state-of-the art microwave spectrometers, sophisticated data analysis, and modern quantum chemistry program packages. Additionally, they learn how to formulate questions and design the research methods. This project uses both cavity-enhanced and chirped-pulse Fourier transform microwave spectroscopy to obtain the rotational spectrum of gas-phase bimolecular heterodimers. A macroscopic, coherent polarization is induced in the free-jet, gaseous sample via a pulse of microwave radiation, which the rotating dimers re-emit at characteristic frequencies in a free-induction decay (FID). The FID is digitized and Fourier transformed to reveal the frequency spectrum that is analyzed to provide molecular structures. The investigation of protic acid-haloethylene complexes tests hypotheses regarding the interplay of electrostatic and dispersion interactions with steric requirements that result in novel and unexpected structures. Through the characterization of non-covalently bonded heterodimers formed between a chiral analyte and a small tag molecule of known chirality, which converts enantiomers of the analyte into spectroscopically-distinguishable diastereomers, the project contributes to the development of a new, improved method of chiral analysis with applications across chemistry and particularly to the pharmaceutical industry. Called chiral tagging, the technique promises to have broad impact by providing the absolute stereochemistry of the analyte and, in a background-free manner, the enantiomeric excess of a sample. Additional broader impacts of this work include the education of undergraduates who are encouraged to pursue careers in STEM fields.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

在这个由化学系化学结构动力学和机理（CSDM-A）项目资助的项目中，Helen O。Leung和Mark D.阿默斯特学院的马歇尔使用高速、最先进的方法来测量两个单独的分子在空间中一起旋转形成的复合物所发出的微波辐射。 分析发射的特定频率的模式以确定复合体的详细形状。 这项研究提供了两个分子如何以精确的距离和角度彼此沿着排列的基本信息。这些信息反过来又表明了分子相互作用的力的性质。 这种力对许多化学和生物系统有重要影响，但很难与更强的化学键的更大影响分开。 该项目旨在提供对分子间相互作用的更好理解。 该研究还利用这些相互作用来区分具有相同物理特性但具有不同生物效应的镜像分子。 从事这项研究的本科生获得了最先进的微波光谱仪，复杂的数据分析和现代量子化学程序包的宝贵实践经验。此外，他们还学习如何制定问题和设计研究方法。本计画利用腔增强与啁啾脉冲傅里叶变换微波光谱技术，获得气相双分子异二聚体的转动光谱。 通过微波辐射脉冲在自由射流气态样品中诱导宏观相干极化，旋转二聚体在自由感应衰减（FID）中以特征频率重新发射微波辐射脉冲。 FID经数字化和傅立叶变换以显示频谱，分析频谱以提供分子结构。 质子酸卤代乙烯复合物的调查测试的假设，静电和分散相互作用的相互作用与空间的要求，导致在新的和意想不到的结构。 通过表征手性分析物和已知手性的小标签分子之间形成的非共价键合的异二聚体，其将分析物的对映异构体转化为光谱可区分的非对映异构体，该项目有助于开发一种新的，改进的手性分析方法，其应用于化学，特别是制药工业。 被称为手性标记，该技术有望通过提供分析物的绝对立体化学以及以无背景的方式提供样品的对映体过量来产生广泛的影响。这项工作的其他更广泛的影响包括鼓励本科生在STEM领域从事职业的教育。该奖项反映了NSF的法定使命，并且通过使用基金会的智力价值和更广泛的影响力进行评估，被认为值得支持审查标准。

项目成果

The microwave spectra and molecular structures of (E)-1-chloro-1,2-difluoroethylene and its complex with the argon atom

(E)-1-氯-1,2-二氟乙烯及其氩原子配合物的微波谱和分子结构

• DOI: 10.1016/j.jms.2021.111520
• 发表时间: 2021
• 期刊: Journal of Molecular Spectroscopy
• 影响因子: 1.4
• 作者: Leung, Helen O.;Marshall, Mark D.;Bozzi, Aaron T.;Horowitz, Jonah R.;Nino, Andres C.;Tandon, Hannah K.;Yoon, Leonard
• 通讯作者: Yoon, Leonard

Exploring the Forces Contributing to Noncovalent Bonding by Microwave Spectroscopy and Structural Characterization of Gas-Phase Heterodimers of Protic Acids with Haloethylenes

通过微波光谱和质子酸与卤代乙烯气相异二聚体的结构表征探索促成非共价键合的力

• DOI: 10.1021/acs.jpca.9b07960
• 发表时间: 2019
• 期刊: The Journal of Physical Chemistry A
• 作者: Leung, Helen O.;Marshall, Mark D.
• 通讯作者: Marshall, Mark D.

The microwave spectra and molecular structures of (E)-1,3,3,3-tetrafluoropropene and its complex with the argon atom

(E)-1,3,3,3-四氟丙烯及其氩原子配合物的微波谱和分子结构

• DOI: 10.1016/j.jms.2020.111379
• 发表时间: 2020
• 期刊: Journal of Molecular Spectroscopy
• 影响因子: 1.4
• 作者: Marshall, Mark D.;Leung, Helen O.;Febles, Olivia;Gomez, Alexandra
• 通讯作者: Gomez, Alexandra

Molecular Structures and Microwave Spectra of the Gas-Phase Homodimers of 3-Fluoro-1,2-epoxypropane and 3,3-Difluoro-1,2-epoxypropane

3-氟-1,2-环氧丙烷和3,3-二氟-1,2-环氧丙烷气相同二聚体的分子结构和微波谱

• DOI: 10.1021/acs.jpca.3c03643
• 发表时间: 2023
• 期刊: The Journal of Physical Chemistry A
• 作者: Marshall, Mark D.;Leung, Helen O.
• 通讯作者: Leung, Helen O.

Straining to Put the Pieces Together: The Molecular Structure of ( E )-1-Chloro-1,2-difluoroethylene–Acetylene from Microwave Spectroscopy

努力将各个部分拼凑在一起：微波光谱法中 (E)-1-氯-1,2-二氟乙烯·乙炔的分子结构

• DOI: 10.1021/acs.jpca.1c05169
• 发表时间: 2021
• 期刊: The Journal of Physical Chemistry A
• 作者: Leung, Helen O.;Marshall, Mark. D.;Mlaver, Eli
• 通讯作者: Mlaver, Eli