Collaborative Research: Structure Sensitive Surface Chemistry - Enantioselectivity on Chiral Surfaces

合作研究：结构敏感表面化学 - 手性表面的对映选择性

• 批准号: 1764270
• 负责人: Charles Sykes
• 金额: $ 24.42万
• 依托单位: Tufts University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-05-15 至 2021-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1764270&HistoricalAwards=false
• 关键词: Collaborative; Research; Structure; Sensitive; Surface

Enantiomers are two molecules that have the same arrangement of chemical bonds, but have three-dimensional structures that are mirror images of each other, like your left and right hands. These 'chiral' chemicals play a central role in living-organisms, where only the left- or right-handed forms are present; but not both. As a result, most biologically active molecules, such as pharmaceuticals, must also be chiral molecules, and they must match the handedness of the biochemicals found in life. However, producing enantiomerically pure forms of molecules is a challenging problem. In this collaborative research project funded by the Chemical Structure Dynamics and Mechanism A (CSDM-A) program of the National Science Foundation Division of Chemistry, Professors Andrew Gellman (Carnegie Mellon University) and Charles Sykes (Tufts University) are studying the chemistry of chiral molecules adsorbed on metal surfaces where the atomic structure also has a specific handedness. Working with their students, Professors Gellman and Sykes are developing curved metal surfaces that present a systematic variation in chiral structures. The designed surfaces enable the study of many atomic configurations with a single sample. Sophisticated spectroscopies map the chemical reactivity across the surface, while isolated chemical reactions are observed using a high-resolution microscope that can map the positions of individual atoms. In addition to providing training opportunities for future scientists, insights gained from the project could guide the design of surfaces for enantiospecific production of chiral chemicals in the pharmaceutical industry. The research targets the surface chemistry of two chiral compounds, tartaric acid (TA) and aspartic acid (Asp), on chiral Cu(hkl) surfaces. Single crystal Cu surfaces are polished into spherical shapes such that each point on the surface of the sphere exposes a plane with a different atomic structure. This makes it very efficient to study the adsorption and surface reactions of TA and Asp on all possible structures of a Cu surface; i.e. all possible Miller indices (hkl). The atomic structures of these surfaces are imaged with and without adsorbed TA and Asp using scanning tunneling microscopy. Independent measurements of TA and Asp decomposition kinetics are made on hundreds of different Cu(hkl) surfaces, all on a single sample. These data elucidate surface reaction rate constants as a function of surface orientation, ks(hkl), and hence enable an understanding of the effect of surface structure on chemical and enantiospecific reactivity. Combined, these data are used to identify those surface orientations with the highest enantioselectivities towards decomposition of the two enantiomers of TA and Asp. Imaging with the scanning tunneling microscope is then used to determine the atomic structure of the surfaces having greatest enantioselectivity.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

对映异构体是两个分子，具有相同的化学键排列，但具有三维结构，它们是彼此的镜像，例如左手和右手。这些“手性”化学物质在只有左或右手形式的生物中起着核心作用。但不是两者。结果，大多数具有生物活性的分子（例如药物）也必须是手性分子，并且它们必须与生命中发现的生化物的惯用性相匹配。 但是，产生对映体纯净的分子形式是一个具有挑战性的问题。在这个由化学结构动力学和机制A（CSDM-A）资助的合作研究项目中，国家科学基金会化学部门（Carnegie Mellon University）和查尔斯·赛克斯（Charles Mellon University）和查尔斯·赛克斯（Charles Sykes）（Tufts University）正在研究Chiral分子化学的化学性能，这些化学也吸附了金属表面上的特定于特定于特定于特定于特定于特定于特定的人的金属表面。 与学生合作，盖尔曼（Gellman）和赛克斯（Sykes）正在开发弯曲的金属表面，这些金属表面呈现出手性结构的系统变化。设计的表面使许多原子构构具有单个样本的研究。 复杂的光谱学绘制了整个表面上的化学反应性，同时使用高分辨率显微镜观察到孤立的化学反应，该显微镜可以映射单个原子的位置。除了为未来的科学家提供培训机会外，从该项目中获得的见解还可以指导制药行业中手性化学物质的表面设计。 该研究针对手性铜（HKL）表面的两种手性化合物（TA）和天冬氨酸（ASP）的表面化学。 单晶铜表面被抛光成球形形状，使得球体表面的每个点都会暴露出具有不同原子结构的平面。 这使得研究TA和ASP在Cu表面的所有可能结构上的吸附和表面反应变得非常有效。即所有可能的米勒指数（HKL）。 这些表面的原子结构使用扫描隧道显微镜在有没有吸附的TA和ASP的情况下成像。 TA和ASP分解动力学的独立测量是在数百种不同的Cu（HKL）表面上进行的，所有这些都在单个样品上。 这些数据阐明了表面反应速率常数是表面取向，KS（HKL）的函数，因此可以理解表面结构对化学和对映体反应性的影响。 这些数据结合在一起，用于识别那些具有最高对映选择性的表面取向，以分解TA和ASP的两个对映异构体。 然后，使用扫描隧道显微镜进行成像来确定具有最大对映选择性的表面的原子结构。该奖项反映了NSF的法定任务，并被认为是值得通过基金会的智力优点和更广泛的影响来通过评估来支持的。

项目成果

Hypothetical Efficiency of Electrical to Mechanical Energy Transfer during Individual Stochastic Molecular Switching Events

单个随机分子切换事件期间电能到机械能转移的假设效率

• DOI: 10.1021/acsnano.0c04082
• 发表时间: 2020
• 期刊: ACS Nano
• 影响因子: 17.1
• 作者: Larson, Amanda M.;Balema, Tedros A.;Zahl, Percy;Schilling, Alex C.;Stacchiola, Dario J.;Sykes, E. Charles
• 通讯作者: Sykes, E. Charles

Low-cost spectrum analyzer for trouble shooting noise sources in scanning probe microscopy

用于排除扫描探针显微镜中噪声源故障的低成本频谱分析仪

• DOI: 10.1116/6.0000410
• 发表时间: 2020
• 期刊: Journal of Vacuum Science & Technology A
• 影响因子: 2.9
• 作者: McQuillan, Nicholas M.;Larson, Amanda M.;Sykes, E. Charles H.
• 通讯作者: Sykes, E. Charles H.

Templated Growth of a Homochiral Thin Film Oxide

同手性薄膜氧化物的模板化生长

• DOI: 10.1021/acsnano.0c00398
• 发表时间: 2020
• 期刊: ACS Nano
• 影响因子: 17.1
• 作者: Schilling, Alex C.;Therrien, Andrew J.;Hannagan, Ryan T.;Marcinkowski, Matthew D.;Kress, Paul L.;Patel, Dipna A.;Balema, Tedros A.;Larson, Amanda M.;Lucci, Felicia R.;Coughlin, Benjamin P.
• 通讯作者: Coughlin, Benjamin P.

Visualizing and Understanding Ordered Surface Phases during the Ullmann Coupling Reaction

• DOI: 10.1021/acs.jpcc.1c00462
• 发表时间: 2021-04-01
• 期刊: JOURNAL OF PHYSICAL CHEMISTRY C
• 影响因子: 3.7
• 作者: Balema，Tedros A.;Miao，Jiayuan;Sykes，E. Charles H.
• 通讯作者: Sykes，E. Charles H.

Controlling Molecular Switching via Chemical Functionality: Ethyl vs Methoxy Rotors

通过化学官能团控制分子开关：乙基与甲氧基转子

• DOI: 10.1021/acs.jpcc.9b06664
• 发表时间: 2019
• 期刊: The Journal of Physical Chemistry C
• 作者: Balema, Tedros A.;Ulumuddin, Nisa;Murphy, Colin J.;Slough, Diana P.;Smith, Zachary C.;Hannagan, Ryan T.;Wasio, Natalie A.;Larson, Amanda M.;Patel, Dipna A.;Groden, Kyle
• 通讯作者: Groden, Kyle