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: 2017
• 资助国家: 加拿大
• 起止时间: 2017-01-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=632483
• 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.

该研究项目的重点是研究用于加速化学过程的表面，这些表面被称为非均相催化剂，其研究具有挑战性，原因如下：首先，表面是一个二维系统，其中几乎包含所有重要的催化剂。化学事件仅在分子与表面直接接触时发生。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，如果表面结合了反应中的任何参与者序列太强，它会堵塞，反应将停止翻转。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，该合金由隔离在相对惰性的金属上的非常活泼的金属原子组成。金属这些类型的表面可以实现两个目标：它们可以限制催化反应所需的贵金属的量；（2）表面上的对映选择性化学的研究。在上一个授权期间（2011-2016），我们在该领域开展了与铂对映选择性氢化相关的明确工作。现在提议转向研究金属表面的对映选择性 CC 偶联反应，即手性产物的合成，其重要性主要取决于化学物质（例如药物）与我们身体的相互作用。从催化基础研究的角度，该研究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。最近，人们对二维碳化物的合成和应用产生了浓厚的兴趣，但人们对它们的表面化学几乎一无所知——除了表面终止对它有深远的影响。我们正在启动对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，他们将具备完全轻松使用复杂仪器的技能，并拥有以下方面的基本专业知识表面和界面的无数应用。