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

获得了来自主要研究仪器（MRI）项目和化学研究仪器（CRIF）项目的奖项，来自弗吉尼亚大学的Brooks Pate教授和他的同事Kevin Lehmann将开发一种新的仪器，该仪器涉及傅立叶变换微波光谱，用于研究手性分子。分子手性是指分子以两种镜像形式存在（称为对映体）而表现出手性的特性，就像人的左手和右手一样。分子的左形态（对映体）与右形态（对映体）的反应可能不同。许多药物可以以两种形式存在。然而，只有一种通常在医学上是有效的。有了这笔奖金，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数量（对映体过量）。该仪器将使用一种最近开发的程序，使用微波光谱仪分析通过共同能级耦合的三个气相旋转转变（三波混频）。该技术在药物制剂或材料研究中反应混合物的分析中具有重要的实际应用价值。该仪器将允许使用三波混合傅立叶变换旋转光谱进行手性分析。该仪器采用宽带啁啾脉冲傅立叶变换旋转光谱的设计原理，它将能够进行三种基本的手性分析测量：(a)在具有多个手性中心的分子合成中产生的非对映体产率的定量测量；(b)定量测量样品中每个非对映体的对映体过量；(c)准确测定过量对映体的绝对构型（或旋向性）。

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.