EAGER: Three-wave mixing techniques to study and utilize nuclear quadrupole coupling effects in chiral molecules

EAGER：三波混合技术研究和利用手性分子中的核四极耦合效应

基本信息

批准号：
1841346
负责人：
Garry Grubbs
金额：
$ 5.98万
依托单位：
Missouri University of Science and Technology
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2018
资助国家：
美国
起止时间：
2018-08-15 至 2020-08-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1841346&HistoricalAwards=false
关键词：
EAGER Three wave mixing techniques

项目摘要

Many molecules in nature, particularly biological molecules, exhibit a handedness in their geometric structure. This is to say two molecules can have the same number and kinds of atoms and geometric arrangement, but they are mirror images of each other, as are one's left and right hands. This "handedness" in chemistry is referred to as "chirality." In chemical measurements, distinguishing between the "hands"- known as enantiomers- and quantifying the amounts of each can be a difficult technological challenge. This difficulty can limit our ability to synthesize and separate a given enantiomer. In this project, funded by the Chemical Structure, Dynamics, and Mechanism (CSDM-A) and Chemical Measurement and Imaging (CMI) Programs of the Chemistry Division, Professor Garry Grubbs II of the Missouri University of Science and Technology is using advanced microwave spectroscopy techniques to determine the type and concentration of enantiomers present in a sample. Microwave spectroscopy provides information about molecular structure based on how fast they can be made to rotate by the microwave radiation. Professor Grubbs hypothesizes that "handedness" of a molecule can be determined if that molecule contains a very heavy atom like bromine or iodine. The nuclei of these heavy atoms contain arrangements of electrical charge that can make the rotations of the overall molecule reveal more about its structure in a microwave experiment than it would otherwise. If Professor Grubbs' hypothesis is correct, there may be new paths toward faster and more accurate synthesis and monitoring of chiral systems, which is particularly important to pharmaceutical research. The project is also training graduate students in currently unexplored areas of physical chemistry using state-of-the-art instrument design as well as new quantum theory development.This project focuses on utilizing the recent discovery of microwave three-wave mixing in chiral systems on nuclear electric quadrupole coupling interactions. These experiments are designed to establish, for the first time, experimental data and theoretical understanding for nuclear spin-based methodologies for identifying and quantifying enantiomeric species in mixtures. Microwave three-wave mixing involves utilizing rotational transitions involving excitation along two molecular axes while detecting along the third axis, creating closed-loop transition energy pathways very similar to a three-level maser system. Electric dipole-forbidden, quadrupole-facilitated transitions occur when off-diagonal nuclear electric quadrupole interactions are on the order of the molecular rotation constants and follow the same closed-loop pathway. These are then leveraged using microwave three-wave mixing because of the technique's sensitivity to phase rather than energy of traditional microwave spectroscopy, allowing for the determination of the off-diagonal sign in a singular experiment for the first time as well as insight into the enantiomer in question. Isotopic substitution spectra analysis are then used to validate the veracity of the experimental results. In addition to the technological and educational impacts, this research may expand the reach of, and molecular information offered from, microwave spectroscopy.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.

自然界中的许多分子，特别是生物分子，在其几何结构中表现出旋手性。这就是说，两个分子可以具有相同的原子数量、种类和几何排列，但它们是彼此的镜像，就像一个人的左手和右手一样。这种“手性”在化学中被称为“手性”。在化学测量中，区分“手”（称为对映体）并量化每种物质的含量可能是一项艰巨的技术挑战。这种困难会限制我们合成和分离给定对映体的能力。在该项目中，由化学系的化学结构、动力学和机理（CSDM-A）和化学测量与成像（CMI）项目资助，密苏里科技大学的 Garry Grubbs II 教授正在使用先进的微波光谱学确定样品中存在的对映异构体的类型和浓度的技术。微波光谱根据微波辐射使分子旋转的速度提供有关分子结构的信息。格鲁布斯教授假设，如果分子含有非常重的原子（如溴或碘），则可以确定该分子的“旋手性”。这些重原子的原子核含有电荷排列，可以使整个分子的旋转在微波实验中比其他方式更多地揭示其结构。如果格鲁布斯教授的假设是正确的，那么可能会出现更快、更准确地合成和监测手性系统的新途径，这对药物研究尤为重要。该项目还利用最先进的仪器设计和新的量子理论发展，在目前尚未探索的物理化学领域培训研究生。该项目的重点是利用手性系统中微波三波混合的最新发现核电四极耦合相互作用。这些实验旨在首次为基于核自旋的方法建立实验数据和理论理解，以识别和量化混合物中的对映体种类。微波三波混合涉及利用涉及沿两个分子轴激发同时沿第三轴检测的旋转跃迁，创建与三能级微波激射系统非常相似的闭环跃迁能量路径。当非对角核电四极相互作用处于分子旋转常数的量级并遵循相同的闭环路径时，会发生电偶极禁止、四极促进的跃迁。然后使用微波三波混合来利用这些技术，因为该技术对相位敏感，而不是传统微波光谱的能量，从而首次在单个实验中确定非对角线符号，并深入了解对映体有问题。然后使用同位素取代谱分析来验证实验结果的准确性。除了技术和教育影响之外，这项研究还可能扩大微波光谱学的范围和提供的分子信息。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查进行评估，被认为值得支持标准。

项目成果

期刊论文数量（6）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Dipole forbidden, nuclear electric quadrupole allowed transitions and chirality: The broadband microwave spectrum and structure of 2-bromo-1,1,1,2-tetrafluoroethane

DOI：
10.1016/j.molstruc.2020.128277
发表时间：
2020-09-15
期刊：
JOURNAL OF MOLECULAR STRUCTURE
影响因子：
3.8
作者：
Isert, Joshua E.;Marshall, Frank E.;Grubbs, G. S.
通讯作者：
Grubbs, G. S.

Theoretical Calculations, Microwave Spectroscopy, and Ring-Puckering Vibrations of 1,1-Dihalosilacyclopent-2-enes

1,1-二卤硅环戊-2-烯的理论计算、微波光谱和环褶皱振动

DOI：
10.1021/acs.jpca.0c07250
发表时间：
2020
期刊：
The Journal of Physical Chemistry A
影响因子：
0
作者：
McFadden, Thomas M.;Marshall, Frank E.;Ocola, Esther J.;Laane, Jaan;Guirgis, Gamil A.;Grubbs, Garry S.
通讯作者：
Grubbs, Garry S.

The Conformational Landscape, Internal Rotation, and Structure of 1,3,5-Trisilapentane using Broadband Rotational Spectroscopy and Quantum Chemical Calculations

使用宽带旋转光谱和量子化学计算研究 1,3,5-三硅戊烷的构象景观、内部旋转和结构

DOI：
10.1021/acs.jpca.0c01100
发表时间：
2020
期刊：
The Journal of Physical Chemistry A
影响因子：
0
作者：
Jabri, Atef;Marshall, Frank E.;Tonks, William Raymond;Brenner, Reid E.;Gillcrist, David J.;Wurrey, Charles J.;Kleiner, Isabelle;Guirgis, Gamil A.;Grubbs, G. S.
通讯作者：
Grubbs, G. S.

The molecular structure and curious motions in 1,1-difluorosilacyclopent-3-ene and silacyclopent-3-ene as determined by microwave spectroscopy and quantum chemical calculations

通过微波光谱和量子化学计算确定 1,1-二氟硅杂环戊-3-烯和硅杂环戊-3-烯的分子结构和奇异运动

DOI：
10.1039/d1cp04286f
发表时间：
2022
期刊：
Physical Chemistry Chemical Physics
影响因子：
3.3
作者：
McFadden, Thomas M.;Moon, Nicole;Marshall, Frank E.;Duerden, Amanda J.;Ocola, Esther J.;Laane, Jaan;Guirgis, Gamil A.;Grubbs, G. S.
通讯作者：
Grubbs, G. S.

A chirped pulse Fourier transform microwave spectrometer with multi-antenna detection

具有多天线检测功能的啁啾脉冲傅立叶变换微波光谱仪

DOI：
10.1016/j.jms.2020.111396
发表时间：
2020
期刊：
Journal of Molecular Spectroscopy
影响因子：
1.4
作者：
Duerden, Amanda;Marshall, Frank E.;Moon, Nicole;Swanson, Christian;Donnell, Kristen M.;Grubbs II, G.S.
通讯作者：
Grubbs II, G.S.