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

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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.