Single-Complex, Single-Molecule, Single-Atom and Single-Site Studies of Chemical Events on Reactive Surfaces

反应表面化学事件的单络合物、单分子、单原子和单位点研究

• 批准号: RGPIN-2017-06483
• 负责人: McBreen, Peter
• 金额: $ 4.37万
• 依托单位: Université Laval
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=659149
• 关键词: Single; Complex; Molecule; Atom; Site

This research program is focused on the study of surfaces that are used to accelerate chemical processes. These surfaces are called heterogeneous catalysts. Their study is challenging area for several reasons. First, a surface is a two-dimensional system where almost all of the important chemical events occur only when the molecules make direct contact with the surface. As a result, the study of chemistry on surfaces requires very sensitive instruments. Second, chemical processes are often only accelerated at certain sites on the surface, so-called active sites. Third, if the surface binds any of the participants in the reaction sequence too strongly, it will clog up and the reaction will stop turning over. In this research program, we will primarily use scanning tunneling microscopy (STM) to study individual reactant molecules, or couples of molecules, at individual sites on precisely defined reactive surfaces. The STM technique can directly image conducting surfaces with atomic or sub-molecular resolution. There are three sub-projects: (1) A study of single-atom alloys (SAA), composed of atoms of a very reactive metal isolated on a relatively inert metal surface. These types of surfaces may achieve two objectives. They might limit the amount of precious metals needed to catalyze reactions. Also, they may prevent the surface from binding reactants or intermediates too strongly; (2) The study of enantioselective chemistry on surfaces. This in an area in which our group a currently doing leading work. During the last granting period (2011-2016), we carried out the definitive body of work on surface phenomena related to enantioselective hydrogenation on platinum. We are now proposing to move to the study of enantioselective CC coupling reactions on metal surfaces. Progress in this area, the synthesis of chiral products, is important for many reasons. Principally, the interaction of chemicals (for example, medicines) with our bodies depends sensitively on the chirality of the chemical. From the perspective of fundamental research in catalysis, the study provides remarkable insight on the use of weak intermolecular interactions to achieve reaction selectivity. (3) The study of two-dimensional metal carbides. We are experts in the surface study of conventional metal carbides. Recently, there has been an explosion of interest in the synthesis and application of 2D carbides. However, almost nothing is known about their surface chemistry-apart from the understanding that the surface termination has a profound affect on the material's properties. We are launching a systematic study of the surface chemistry of 2D carbides. HQP will directly perform all of the experimental surface science measurements in all of the projects. They will graduate with the skill of being completely at ease with complex instrumentation, and with fundamental expertise in the myriad applications of surfaces and interfaces.

该研究计划的重点是研究用于加速化学过程的表面。这些表面称为多相催化剂。由于多种原因，他们的研究是一个具有挑战性的领域。首先，表面是一个二维系统，几乎所有重要的化学事件只有当分子与表面直接接触时才会发生。因此，表面化学研究需要非常灵敏的仪器。其次，化学过程通常仅在表面的某些位点（即所谓的活性位点）加速。第三，如果表面与反应序列中的任何参与者的结合太强，它就会堵塞并且反应将停止转动。在这个研究项目中，我们将主要使用扫描隧道显微镜（STM）来研究精确定义的反应表面上各个位点的单个反应物分子或一对分子。 STM 技术可以以原子或亚分子分辨率直接对导电表面进行成像。共有三个子项目：（1）单原子合金（SAA）的研究，由隔离在相对惰性的金属表面上的非常活泼的金属原子组成。这些类型的表面可以实现两个目标。它们可能会限制催化反应所需的贵金属的量。此外，它们还可以防止表面与反应物或中间体的结合过强； (2)表面对映选择性化学研究。这是我们小组目前正在做主导工作的领域。在上一个授权期间（2011-2016），我们对与铂对映选择性氢化相关的表面现象进行了明确的工作。我们现在提议转向研究金属表面上的对映选择性 CC 偶联反应。出于多种原因，手性产物的合成这一领域的进展非常重要。原则上，化学物质（例如药物）与我们身体的相互作用敏感地取决于化学物质的手性。该研究从催化基础研究的角度出发，为利用弱分子间相互作用实现反应选择性提供了非凡的见解。 (3)二维金属碳化物的研究。我们是传统金属碳化物表面研究的专家。最近，人们对二维碳化物的合成和应用产生了浓厚的兴趣。然而，人们对它们的表面化学几乎一无所知——除了了解表面终止对材料性能有深远影响之外。我们正在启动二维碳化物表面化学的系统研究。 HQP 将直接执行所有项目中的所有实验表面科学测量。他们毕业时将具备完全轻松使用复杂仪器的技能，并具备表面和界面的无数应用的基本专业知识。