Chemical Applications of Vibrational Circular Dichroism Spectroscopy

南加州大学的Philip J. Stephens博士获得了化学系物理化学项目的资助，用于他对振动圆二色光谱的化学应用的研究。Stephens博士将开发用于测量和预测手性分子的振动圆二色性（VCD）光谱的仪器和理论方法，并将VCD光谱应用于手性分子的立体化学的阐明。 一种双调制方法将被实施，以减少偏振伪影和提高VCD仪器的灵敏度。 从头算DFT/GIAO方法预测振动旋转强度将改善列入非谐性和溶剂效应。 应用主要集中在绝对构型的确定和构象分析。手性分子存在两种形式--对映体--它们是镜像。 药物分子对映体的不同生化行为导致了单一对映体手性药物的发展。 因此，有效地表征手性分子结构的方法越来越重要。 Stephens博士将开发振动圆二色性（VCD）光谱学的方法，这是一种研究手性分子的技术。 新的方法将被开发用于测量和预测VCD光谱，其精确度比迄今为止可能的要高得多，这反过来又将大大提高VCD光谱学在手性分子（包括手性药物）的结构表征中的应用。 研究生和博士后助理将接受这些技术的培训。

Dr. Philip J. Stephens of the University of Southern California is funded for his research on chemical applications of vibrational circular dichroism spectroscopy by a grant in the Physical Chemistry program of the Chemistry Division. Dr. Stephens will develop instrumental and theoretical methods for the measurement and prediction of the vibrational circular dichroism (VCD) spectra of chiral molecules and will apply VCD spectroscopy to the elucidation of the stereochemistries of chiral molecules. A dual-modulation methodology will be implemented for the reduction of polarization artefacts and the enhancement of the sensitivity of VCD instrumentation. The ab initio DFT/GIAO methodology for predicting vibrational rotational strengths will be improved by inclusion of anharmonicity and solvent effects. Applications will focus on the determination of absolute configuration and conformational analysis.Chiral molecules exist in two forms - enantiomers - which are mirror images. The different biochemical behavior of enantiomers of a pharmaceutical molecule is leading to increasing development of single enantiomer, chiral drugs. Methods for efficiently characterizing the structures of chiral molecules are therefore of increasing importance. Dr. Stephens will develop the methodology of vibrational circular dichroism (VCD) spectroscopy, a technique for studying chiral molecules. New methods will be developed for measuring and predicting VCD spectra with much greater accuracy than heretofore possible, which in turn will greatly enhance the application of VCD spectrosopy to the structural characterization of chiral molecules, including chiral drugs. Graduate students and postdoctoral associates will be trained in these techniques.