Molecular rotors for studying transition state stabilization by non-covalent interactions

用于研究非共价相互作用过渡态稳定性的分子转子

• 批准号: 2003889
• 负责人: Ken Shimizu
• 金额: $ 44.75万
• 依托单位: University of South Carolina at Columbia
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-08-01 至 2024-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2003889&HistoricalAwards=false
• 关键词: Molecular; rotors; studying; transition; state

Professor Ken D. Shimizu of the University of South Carolina is supported by the Macromolecular, Supramolecular, and Nanochemistry Program in the Division of Chemistry to investigate the role of non-bonding interactions in the stabilization of the transition state between reactants and products. Catalysts are frequently used to speed up chemical reactions and make them more selective for the desired product. A key challenge in catalysis development is enhancing the ability of catalysts to bring together molecules into crowded reactive structures know as transitions states. Professor Shimizu and his students are constructing molecular machines (rotors) that assist in the fundamental understanding and optimization of catalyst reactivity. The molecular rotors are designed to assess factors that simplify the formation of these crowded reactive structures via changes in the speed of their rotation. Thus, the molecular rotors provide a simple and systemic way to study and improve catalyst design. The development of new and improved catalysts enables the efficient production of new chemicals, polymers, fuels, and pharmaceuticals. Graduate and undergraduate students are trained in research methods, in particular women chemists through a collaboration with faculty and students at a local women’s college. A graduate course is developed to provide students with fundamental skills, such as how to present seminars, time and research management strategies, and how to write research publications and proposals. The ability of non-covalent interactions to stabilize transition states is measured using a series of molecular rotors. The rotors form non-covalent interactions in their planar transition states. The stabilizing effects of the non-covalent interactions can be measured from the increase in speed of the molecular rotors. The versatility and modularity of the rotor framework enables the study of a wide range of non-covalent interactions including hydrogen bonds, cation-pi, anion-pi, n-pi*, chalcogen-chalcogen, CH-pi, arene-arene, OH-pi, and metal-pi interactions. The transition state effects are easily and accurately assessed by measuring the rotational barriers using dynamic NMR spectroscopy. Finally, the rigid framework limits the degrees of freedom in the ground and transition states enabling accurate modeling and simulation using standard DFT methods, which provide computational-corroboration of the experimentally measured barriers, transition state structures, and insights into the origins of the stabilizing effects. The project broadly impacts the development of new strategies to improve synthetic catalysts and provides insights into the large rate accelerations in enzymatic systems. In addition, the development of a new strategy for studying and interrogating transition state energies using molecular rotors provides chemists with new tools for fundamental kinetic studies.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.

南卡罗来纳大学的Ken D. Shimizu教授得到了化学部的大分子，超分子和纳米化学计划的支持，以研究非键相互作用在反应剂与产品之间过渡状态的稳定中的作用。催化剂经常用于加快化学反应的速度，并使它们对所需产品更具选择性。催化开发的一个关键挑战是增强催化剂将分子聚集到拥挤的反应性结构中的能力，因为过渡状态知道。 Shimizu教授和他的学生正在构建分子机器（转子），以帮助催化剂反应性的基本理解和优化。分子转子旨在评估通过变化旋转速度来简化这些拥挤的反应性结构形成的因素。这，分子转子提供了一种简单而系统的研究方法来研究和改善催化剂设计。新的和改进的催化剂的开发可以有效地生产新的化学物质，聚合物，燃料和药物。研究生和本科生接受了研究方法的培训，尤其是通过与当地女性学院的教职员工和学生合作的女性化学家。开发研究生课程旨在为学生提供基本技能，例如如何提出半手，时间和研究管理策略，以及如何撰写研究出版物和建议。使用一系列分子转子测量了非共价相互作用稳定过渡态的能力。转子在其平面过渡状态下形成非共价相互作用。非共价相互作用的稳定作用可以通过分子转子速度的增加来测量。转子框架的多功能性和模块化使得可以研究多种非共价相互作用，包括氢键，阳离子 - Pi，Anion-Pi，n-Pi*，chalcogen-chalcogen，chalcogen-chalcogen，ch-pi，ch-pi，ch-pi，arene-rene-arene，oh-pi，oh-pi和金属pi相互作用。通过使用动态NMR光谱测量旋转屏障，可以轻松，准确地评估过渡状态的效应。最后，刚性框架限制了地面上的自由度，过渡状态可以使用标准DFT方法进行准确的建模和仿真，从而提供了对实验测量的障碍，过渡状态结构的计算 - 腐败方法，以及对稳定效应的起源的见解。该项目广泛地影响了改善合成催化剂的新策略的发展，并提供了对酶促系统中较大速率加速的见解。此外，开发了使用分子转子研究和询问过渡状态能量的新策略，为化学家提供了用于基本动力学研究的新工具。该奖项反映了NSF的坚定使命，并使用基金会的知识分子优点和更广泛的影响标准来评估值得支持。

项目成果

Pnictogen Interactions with Nitrogen Acceptors

氮元素与氮受体的相互作用

• DOI: 10.1002/anie.202304960
• 发表时间: 2023
• 期刊: Angewandte Chemie International Edition
• 作者: Lin, Binzhou;Liu, Hao;Karki, Ishwor;Vik, Erik C.;Smith, Mark D.;Pellechia, Perry J.;Shimizu, Ken D.
• 通讯作者: Shimizu, Ken D.

Electrostatically-gated molecular rotors

静电门控分子转子

• DOI: 10.1039/d2cc00512c
• 发表时间: 2022
• 期刊: Chemical Communications
• 影响因子: 4.9
• 作者: Lin, Binzhou;Karki, Ishwor;Pellechia, Perry J.;Shimizu, Ken D.
• 通讯作者: Shimizu, Ken D.