CAREER:Single-Molecule Spectroscopy as a Mechanistic Tool for Studying Catalyst Reaction Dynamics

该奖项由化学系化学结构、动力学和机制-B项目资助，将使威斯康星大学麦迪逊分校的兰德尔·H·戈德史密斯教授能够开发和应用工具，能够观察单个分子催化剂在更替条件下的非同步化学动力学。这些方法将能够确定瞬时中间体的形成和耗尽的动力学以及催化剂行为的时间波动，包括变换速率常数和对映体选择性。这些微观行为对整体反应动力学的影响将被探索。测量将通过时间分辨荧光显微镜进行。荧光团的设计、化学合成以及等离子体纳米结构的制造和部署是这一方法的关键要素。综上所述，这些活动将使人们能够确定催化分子动力学的年表，这将增加对反应机理的新见解，并指导未来催化剂开发的战略。在人类在日常生活中所能进行的所有宏观观察之下，是一个在单分子微观层面上搅动、充满活力和动态的世界。通过对单分子进行测量，这一提议致力于消除宏观和微观世界之间的脱节，达到两个目的。首先，单分子的混乱性质隐藏了分子行为，这些行为对工业上有用的化学反应具有重要影响。揭示单个催化剂分子的分子动力学，使具有挑战性的化学反应成为可能，将使人们更好地了解它们的操作模式，从而为设计新的、更有效的催化剂和更便宜、更环保的化学物质铺平道路。其次，消除这种脱节对化学教育有重要的影响，因为从微观上理解化学自然就会理解宏观上的化学行为。几乎没有教育实验可以让学生和非科学家真正“看到”单分子。这项提案包含一项紧密结合的推广活动，旨在建造一种坚固和便携的显微镜，使用户能够用肉眼看到单分子。这一教育工具将在博物馆和学校建立并用于新的化学教育举措，包括那些在科学和技术职业生涯中学生比例较低的学校。

This award, funded by the Chemical Structure, Dynamics, and Mechanisms-B Program of the Division of Chemistry, will enable Professor Randall H. Goldsmith of the University of Wisconsin Madison to develop and apply tools that enable the observation of unsynchronized chemical dynamics of individual molecular catalysts under turnover conditions. These methods will enable determination of the kinetics of formation and depletion of transient intermediates and temporal fluctuations of catalyst behavior, including shifting rate constants and enantioselectivity. The impact of these microscopic behaviors on bulk reaction dynamics will be explored. Measurements will be made via time-resolved fluorescence microscopy. Fluorophore design, chemical synthesis, and fabrication and deployment of plasmonic nanostructures are critical elements of this approach. Taken together, these activities will allow determination of a chronology of the molecular dynamics of catalysis that will add new insights on reaction mechanism and guide strategies for future catalyst development. Underneath all macroscopic observations that humans can make in everyday life is a churning, vibrant, and dynamic world at the microscopic level of single molecules. By making measurements on single molecules, this proposal endeavors to remove the disconnect between the macro- and micro-world for two purposes. First, the chaotic nature of single molecules hides molecular behavior that has important consequences for industrially useful chemical reactions. Revealing the molecular dynamics of individual catalyst molecules, molecules that enable challenging chemical reactions, will allow greater understanding of their mode of operation, leading the way to the design of new and more effective catalysts and cheaper and "greener" chemistry. Second, removing this disconnect has important consequences for chemical education, as understanding chemical behavior on the macro-scale flows naturally from understanding chemistry at the micro-scale. Few educational experiments exist that can allow students and non-scientists to truly "see" single molecules. This proposal contains a closely integrated outreach activity to build a robust and portable microscope that will allow users to see single molecules with the naked eye. This educational tool will be built and used for new chemical education initiatives in museums and schools, including those with large components of students under-represented in science and technology careers.