CAREER: Physical organic approach to obtaining chemomechanical reaction parameters of diverse functional groups

美国伊利诺伊大学香槟分校化学系教授罗曼·博拉托夫在美国国家科学基金会有机和高分子化学项目的支持下，开展了集有机合成、动力学测量和计算于一体的研究，开发了一种获得不同官能团反应的化学力学参数的方法。这些参数量化了反应速率如何受到作用于反应物单个原子的外部介观作用力的影响。他们需要在5纳米到50纳米的尺度上对过程的动力学进行建模。在这些尺度上，动力学通常由几个化学键的重排控制，重排速度取决于数百万原子之间的非平衡相互作用。在这种情况下，无论是标准的化学动力学模型，还是牛顿定律本身都是不够的。在化学机械方法中，整个过程的动力学被建模为受外部机械力扰动的小分子反应。这种方法提供了一个机会来理解当代人们非常感兴趣的现象，如三磷酸腺苷合成酶的运作、生物动力、材料在机械应力下的降解以及摩擦化学。刺激响应材料、可能的分子机械装置和自主纳米机械装置的合理设计需要潜在的化学反应的定量的化学机械参数。PI的小组将开发小的(1 KDa)双功能分子，其中一个部分(执行器)的光异构化将在立体电子不同的官能团(机械团)上施加超过1NN的机械力，以及将机械力整合到化学动力学形式中的非经验方法。这一职业奖项的广泛影响在于开发了一种简单、通用的方法来量化外部介观作用力如何影响不同的化学反应速率。在发展和改进这一方法的过程中，Pi的小组将从原子角度理解抑制力对光异构化量子产率的影响，以及在不同的实验条件下通过合成修饰分子光致动器和电环反应以及S-S键的异解和均裂的速率/力关系来最大化光异构化量子产率的策略。拟议的研究将促进科学、技术、工程和数学(STEM)学科的人力资源开发，涉及服务不足的高中生、HS STEM教师和研究生指导下的第一代本科生，以及博士后研究员。将使用两个项目来实现这一目标：-STIR(通过综合研究进行科学教学)：正在进行的PI牵头的合作，旨在提高农村高中生的科学素养。STIR整合了NSF计划的元素，如教师研究经验(RET)、高中生研究经验(REHS)和K-12教育研究生教学研究员(GK-12)活动，并将同行指导策略纳入HS化学教学。-FIRST(培养研究、研究和教学的独立性)：一项旨在解决主要研究型大学第一代大学生面临的特殊需求和挑战的综合倡议。该项目的跨学科性质为国家未来一代科学家提供了一个极好的培训基础。

Professor Roman Boulatov, of the Department of Chemistry at University of Illinois- Urbana-Champaign, is supported by the Organic and Macromolecular Chemistry Program at the National Science Foundation to perform research integrating organic synthesis, kinetic measurements and computations to develop a method to obtain chemomechanical parameters of reactions of diverse functional groups. Such parameters quantify how reaction rates are affected by external mesoscopic forces acting at individual atoms of the reactants. They are required to model the dynamics of processes at scales between 5 nm and 50 nm. At these scales the dynamics is often governed by rearrangements of a few chemical bonds at rates that depend on non-equilibrium interaction among millions of atoms. In this regime, neither the standard chemical kinetics models, nor Newton laws alone are adequate. Within the chemomechanical approach, the dynamics of the whole process is modeled as a small-molecule reaction perturbed by external mechanical forces. This approach provides an opportunity to understand phenomena of intense contemporary interest, such as operation of ATP-synthase, biological motility, degradation of materials under mechanical stress, and tribochemistry. The rational design of stimuli responsive materials and putative molecular mechanical devices and autonomous nanomechanical devices requires quantitative chemomechanical parameters of underlying chemical reactions. The PI's group will develop small (1 kDa) bifunctional molecules in which photoisomerization of one moiety (actuator) will exert mechanical forces over 1 nN on stereoelectronically diverse functional groups (mechanophores) and non-empirical approaches to integrate mechanical forces into chemical kinetics formalisms.Broader impacts of this CAREER award lie in the development of a simple, general method to quantify how external mesoscopic force affects rates of diverse chemical reactions. In the course of developing and refining this method the PI's group will obtain atomistic understanding of the effect of a restraining force on quantum yields of photoisomerization and strategies to maximize the yield by synthetic modifications of molecular photoactuators and rate/force relationships for electrocyclic reactions and heterolytic and homolytic scission of the S-S bond under various experimental conditions. The proposed research will facilitate human resource development in Science, Technology, Engineering and Mathematics (STEM) disciplines by involving underserved high-school (HS) students, HS STEM teachers and first-generation undergraduates under the guidance of graduate students, and postdoctoral fellows. Two Programs will be use to accomplish this:- STIR (Science Teaching through Integrated Research): an ongoing PI-lead collaboration aimed improving the scientific literacy of rural high school students. STIR integrates elements of NSF Programs such as Research Experience for Teachers (RET), Research Experience for High Schoolers (REHS), and Graduate Teaching Fellows in K-12 Education (GK-12) activities and incorporates peer-mentoring strategies into HS Chemistry teaching.- FIRST (Fostering Independence in Research, Studies and Teaching): a comprehensive initiative aimed at addressing specific needs and challenges faced by first-generation college students at a major research university.The interdisciplinary nature of the project forms an excellent training ground for the future generation of nation's scientists.