RUI: Isotopically Different Tunneling-Ready-State Structures in Hydride Transfer Reactions in Solution

本课题由化学系化学结构与动力学机制B项目资助，吕云教授、詹姆斯·E. Eilers和Kevin R.南伊利诺伊大学爱德华兹维尔分校化学系的塔克正在研究人体内的反应是如何起作用的。氢转移反应在化学和生物学中很常见。 体内约50%的生物反应涉及氢转移。 这个项目可以帮助科学家了解这些生物过程。 该项目涉及三个不同化学领域（有机，分析和计算）的专业知识。南伊利诺伊大学爱德华兹维尔分校（SIUE）的化学系举办了针对圣路易斯东部地区高中教师的研讨会，该地区有大量非洲裔美国人生活在贫困线以下。该计划为研究团队提供了一个机会，让高中教师和学生参与该项目，为他们上大学和STEM职业做好准备。 该项目研究了当代氢（H）波传输模型中的一个新概念，即，H隧道新的概念是H隧穿和它的较重同位素（氘（D）或氚（T））隧穿在隧穿就绪态（TRS）结构处具有不同的施主-受主距离（DAD），这是由于不同的质量从而不同的波动性质。由于较重的同位素具有较短的波长，其转移需要较短的供体-受体距离（DAD）。这一概念的确立将改变传统的氢转移化学和动力学同位素效应理论。 研究人员使用物理有机机理分析方法来区分溶液中各种氢化物与氘转移反应的同位素不同的TRS结构。 他们计划研究次级KIE的主要同位素依赖性，以区分同位素不同的TRS构象。 他们还调查了哈米特相关性的主要同位素依赖性，以区分同位素不同的TRS电子结构。该奖项反映了NSF的法定使命，并被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

In this project, funded by the Chemical Structure, Dynamics & Mechanisms B Program of the Chemistry Division, Professors Yun Lu, James E. Eilers, and Kevin R. Tucker of the Department of Chemistry at Southern Illinois University Edwardsville are investigating how reactions in the human body work. Hydrogen transfer reactions are common in chemistry and biology. About 50% of the biological reactions in the body involve hydrogen transfer. This project may help scientists understand these biological processes. The project involves expertise in three different areas of chemistry (organic, analytical and computational). The chemistry department at Southern Illinois University Edwardsville (SIUE) holds workshops that target high school teachers in the St. Louis Metro-East area, which has a large African-American population living below the poverty line. This program provides an opportunity for the research teams to involve the high school teachers and their students in the project, preparing them for college and a STEM career. The project investigates a new concept in the contemporary models for hydrogen (H)-wave transfer, i.e., H-tunneling. The new concept is that H-tunneling and its heavier isotope (deuterium (D) or tritium (T))-tunneling have different donor-acceptor distance (DAD) at the tunneling-ready-state (TRS) structures due to different masses thus different wave properties. Since a heavier isotope possesses shorter wavelength, its transfer requires a shorter donor-acceptor distance (DAD). The confirmation of the concept could change the traditional views about the H-transfer chemistry and the theory of the kinetic isotope effects (KIE). The investigators use physical organic mechanistic analysis methods to distinguish the isotopically different TRS structures for various hydride- vs. deuteride-transfer reactions in solution. They plan to study the primary isotope dependence of the secondary KIEs to distinguish the isotopically different TRS conformations. They also investigate the primary isotope dependence of Hammett correlations to differentiate the isotopically different TRS electronic structures.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.