MRI: Development of Three Wave Mixing Spectrometer for Chiral Analysis by Rotational Spectroscopy

凭借主要研究仪器（MRI）计划和化学研究仪器（CRIF）计划的这一奖项，来自弗吉尼亚大学的布鲁克斯佩特教授和同事凯文莱曼将开发一种新的仪器，该仪器涉及傅立叶变换微波光谱法用于手性分子的研究。 分子手性是指分子以两种镜像形式（称为对映体）存在，表现出手性的性质，就像人类的左手和右手一样。分子的左形式（对映异构体）可能与其右形式（对映异构体）反应不同。 许多药物可以以两种形式存在。然而，通常只有一种药物是有效的。有了这个奖项，该团队将开发一种仪器来分析样品，以确定给定样品中每种对映体的相对量（对映体过量）。该仪器将使用最近开发的程序，使用微波光谱仪，分析通过共同能级耦合的三个气相旋转跃迁（三波混频）。该技术可在药物制备或材料研究中使用的反应混合物的分析中具有重要的实际应用。 该仪器将允许使用三波混合傅里叶变换旋转光谱进行手性分析。该仪器使用已经为宽带、啁啾脉冲傅里叶变换旋转光谱学开发的设计原理，并且它将能够进行三个基本的手性分析测量：（a）在具有多个手性中心的分子的合成中产生的非对映体的产率的定量测量;（B）样品中每种非对映体的对映体过量的定量测量;和（c）准确测定过量的对映异构体的绝对构型（或手性）。

With this award from the Major Research Instrumentation (MRI) Program and the Chemistry Research Instrumentation (CRIF) Program, Professors Brooks Pate and colleague Kevin Lehmann from the University of Virginia will develop a new instrument that involves Fourier transform microwave spectrometry for the study of chiral molecules. Molecular chirality is the property of molecules to exhibit handedness by existing in two forms (called enantiomers) which are mirror images, like left and right hands in humans. A molecule's left form (enantiomer) may react differently than its right form (enantiomer). Many pharmaceuticals can exist in both forms. However, only one will generally be medically effective. With this award the team will develop an instrument to analyze samples to determine the relative amounts of each enantiomer in a given sample (enantiomeric excess). The instrument will use a recently developed procedure using a microwave spectrometer involving analysis of three gas phase rotational transitions which are coupled through common energy levels (three wave mixing). This technique could have important practical applications in the analysis of reaction mixtures employed in drug preparations or materials research. The instrument would allow chiral analysis using three wave mixing Fourier transform rotational spectroscopy. The instrument uses design principles that have been developed for broadband, chirped-pulse Fourier transform rotational spectroscopy and it will be capable of making three essential chiral analysis measurements: (a) quantitative measurement of the yields of diastereomers produced in the synthesis of a molecule with multiple chiral centers; (b) quantitative measurement of the enantiomeric excess of each diastereomer in a sample; and (c) accurate determination of the absolute configuration (or handedness) of the enantiomer that is in excess.