Spectroscopic Signatures of Chirality Recognition, Transfer and Amplification: from the Gas Phase to Solution and Interfaces

手性识别、传递和放大的光谱特征：从气相到溶液和界面

• 批准号: RGPIN-2018-04944
• 负责人: Xu, Yunjie
• 金额: $ 6.85万
• 依托单位: University of Alberta
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=712615
• 关键词: Spectroscopic; Signatures; Chirality; Recognition; Transfer

A molecule is chiral if its mirror image cannot be superimposed onto itself, just like our right and left hands. Because of the similarity of a pair of mirror images, replacing one with its mirror image, may, in many instances, introduce little or no change in the properties of the associated system. In a chirality recognition event when a chiral molecule interacts with another chiral molecule or chiral light, however, the effect of chirality is prominent, just as in the case of a human handshake (i.e. how different a right/right versus a left/right handshake feels). More generally, chirality is ubiquitous in biological systems and essential for life. Chirality recognition is at the heart of many biological processes including those involving pharmaceuticals and is of chief importance in stereoselective chemistry. We aim to understand the effects of solvent and light radiation on chirality recognition and transfer events at the molecular level in order to formulate rigorous chirality recognition and transfer models with predictive power and to develop new strategies to control these events with light. We will pursue innovative research activities in four core directions which are unified under the central theme of chirality and chirality recognition in the next funding cycle: 1) In order to follow the first few crucial steps of aggregation and solvation in unprecedented detail, we will apply chirped-pulse microwave spectroscopy to study clusters of chiral molecules and solvent molecules with increasing number of subunits. Such larger clusters have rarely been investigated before. 2) We will utilize two powerful chiroptical tools, namely vibrational circular dichroism and Raman optical activity spectroscopy to probe non-covalent interactions and chirality transfer in solution. We will focus on mechanisms of chirality transfer/amplification under (near) resonance which have hardly been explored before. 3) Building on our prior success in instrument development, we will further develop our hybrid mass-laser spectroscopic instrument by coupling it to a helium nanodroplet isolation spectrometer. The hybrid laser-mass instruments will allow us not only to probe chirality recognition in aggregates of amino acids and peptides at room temperature and at 0.4 K, but also to access reaction intermediates by utilizing the gentle helium matrix to stabilize them. 4) We will explore chirality recognition and induction at liquid-liquid interfaces, a new research direction we initiated. The outcome of the proposed research will be valuable to many subfields in chemistry, physics, and biology where chirality plays a significant role. The fundamental knowledge gained will be important for developing a broad range of chiral technologies from sensors for pharmaceutical processes and environmental monitoring to novel catalysts for chiral drug syntheses.

如果一个分子的镜像不能叠加到它自身上，就像我们的右手和左手一样，那么这个分子就是手性的。由于一对镜像的相似性，在许多情况下，用其镜像替换一个镜像可能会对相关系统的属性产生很小的变化或不产生变化。然而，在手性识别事件中，当一个手性分子与另一个手性分子或手性光相互作用时，手性的影响是突出的，就像在人类握手的情况下一样（即右/右与左/右握手感觉有多大不同）。更一般地说，手性在生物系统中无处不在，对生命至关重要。手性识别是许多生物过程的核心，包括那些涉及药物的过程，并且在立体选择性化学中具有首要重要性。 我们的目标是了解溶剂和光辐射对分子水平上的手性识别和转移事件的影响，以制定严格的手性识别和转移模型的预测能力，并开发新的策略来控制这些事件与光。在下一个资助周期，我们将在手性和手性识别的中心主题下，在四个核心方向上开展创新研究活动：1）为了以前所未有的细节跟踪聚集和溶剂化的前几个关键步骤，我们将应用啁啾脉冲微波光谱研究手性分子和溶剂分子的簇，并增加亚基的数量。这样大的集群以前很少被研究过。2)我们将利用两个强大的手性工具，即振动圆二色性和拉曼光学活性光谱探测溶液中的非共价相互作用和手性转移。我们将集中在（近）共振下的手性转移/放大的机制，以前几乎没有探索。3)在我们之前在仪器开发方面取得成功的基础上，我们将进一步开发我们的混合质谱激光光谱仪，将其与氦纳米液滴分离光谱仪耦合。混合激光-质谱仪器将使我们不仅能够在室温和0.4 K下探测氨基酸和肽聚集体中的手性识别，而且还可以通过利用温和的氦基质来稳定反应中间体。4)我们将探索在液-液界面的手性识别和诱导，这是我们开创的一个新的研究方向。 这项研究的结果对于化学、物理和生物学中手性起重要作用的许多子领域都有价值。所获得的基础知识将是重要的，为开发广泛的手性技术，从传感器的制药工艺和环境监测的手性药物合成的新型催化剂。