Chiroptical Spectroscopic Studies on Supramolecular Aggregates

化学系的化学结构、动力学和机理(CSDM-A)项目获得这一奖项，资助范德比尔特大学的Prasad Polavarapu教授研究“手性”分子--也就是与之相关的手性分子。左手手性分子和右手镜像分子之间的药理活性差异使得有必要将这些分子彼此分离以研究它们的性质。Polavarapu博士的团队专门研究手性表面活性剂分子，这些分子形成具有包封性的特殊聚集体结构(例如，用于药物输送)。他们寻求更好地了解这些分子的性质，以便更好地控制和使用。范德比尔特大学和田纳西州立大学的学生通过与Nsoki Phambu博士的合作，有望为对STEM学科感兴趣的本科生提供宝贵的研究培训机会。工作重点是基于酒石酸化学模板的手性聚集体。最近发展起来的振动圆二色谱(VCD)以及电子圆二色谱(ECD)和旋光色散(ORD)被用来探测聚集体。使用这些工具和来自电子显微镜和原子力显微镜等方法的附加数据来确定手性聚集体的三维分子结构。分子动力学模拟提供了对可能结构的进一步了解。通过对手性光谱性质的量子化学预测以及与相应的实验观测结果的比较，进一步揭示了手性聚集体与其光谱性质之间的关系。这些研究有望帮助建立手性聚集体的结构和手性之间的关系。这项工作也有望更好地定义手性光谱方法表征手性聚集体的分析能力。

With this award, the Chemical Structure, Dynamics, and Mechanisms (CSDM-A) Program of the Division of Chemistry is funding Professor Prasad Polavarapu at Vanderbilt University to study "chiral" molecules - that is, molecules with handedness associated with them. Differences in pharmacological activity between a left-handed chiral molecule and its right-handed mirror image make it necessary to isolate these molecules from one another to investigate their properties. Dr. Polavarapu's group specifically studies chiral surfactant molecules which form special aggregate structures with encapsulation properties (used, for example, for drug delivery). They seek improved understanding of the properties of these molecules to enable better control and use. Involvement of students from both Vanderbilt and Tennessee State University through collaboration with Dr. Nsoki Phambu, is expected to provide valuable research training opportunities for undergraduates interested in the STEM disciplines.The work focuses on chiral aggregates based on tartaric acid chemical templates. Recently developed vibrational circular dichroism (VCD) is used to probe the aggregates, along with established electronic circular dichroism (ECD) and optical rotatory dispersion (ORD). Three-dimensional molecular structures of chiral aggregates are determined with these tools and additional data from methods such as electron microscopy and atomic force microscopy. Molecular dynamics simulations provide further understanding of possible structures. Quantum chemical predictions of chiroptical spectroscopic properties and comparison to corresponding experimental observations are used to further unravel the relation between chiral aggregates and their spectroscopic properties. These studies are expected to help establish the relationship between the structures of chiral aggregates and their chiroptical properties. This work is is also expected to better define the analytical capabilities of chiroptical spectroscopic methods for characterizing chiral aggregates.