RUI: Spectroscopic Characterization and Low Temperature Kinetic Study of Hydrogenated Aromatic Radicals

在化学系化学结构、动力学和机理A （CSDM-A）项目的支持下，宾夕法尼亚州立大学erie分校的Jay Amicangelo教授正在利用基质分离红外光谱和计算化学研究氢原子与单取代苯环反应产生的氢化自由基的红外光谱和形成动力学。氢化芳香族自由基被认为是热解、燃烧、氢化和氢解等不同化学过程中的重要中间体。由于缺乏实验红外光谱和氢化自由基在低温下的形成动力学数据，对这些物质作为各种重要化学过程中可能的中间体的性质的完全理解仍然是难以捉摸的。Amicangelo教授和他的学生将利用微波放电源和合适的前体分子，将氢原子和环分子共沉积在氩气基质中，以获得氢化自由基的红外光谱并进行动力学研究。他们的研究可以扩展红外光谱表征氢化自由基的数量，并为其形成动力学提供新的低温数据。米开朗基罗研究小组还将参与一项外展活动，带着便携式科学设备参观伊利学区的高中化学课堂，帮助化学教师让学生有机会亲自动手，进行高质量的科学实验室实验。本课题主要利用矩阵隔离红外光谱和量子化学计算方法，研究氢原子与单取代苯环（C6H5X, X = OCH3, CH3, Cl， CN）反应形成的氢化自由基的红外光谱特征和动力学。芳烃环的氢化自由基被认为是热解、燃烧、氢化和氢解等重要化学过程中的重要中间体。氢化自由基的红外光谱表征将通过微波放电源与合适的前体分子，并将氢原子与环分子共沉积在15k氩基体中来完成。氢化自由基的动力学研究包括在10 K时捕获氩基体中的氢原子，然后在14 - 20 K温度范围内监测氢原子与氩基体中的环分子反应时自由基的生长动力学。这些瞬态中间体的红外光谱将为芳香底物的重要转化机制提供非常有价值的窗口，因此，将对合成，机械和计算化学社区具有广泛的价值。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

With support from the Chemical Structure, Dynamics, and Mechanisms A (CSDM-A) program in the Division of Chemistry, Professor Jay Amicangelo of Pennsylvania State University-Erie is investigating the infrared spectra and formation kinetics of hydrogenated radicals produced by the reactions of hydrogen atoms with monosubstituted benzene rings using matrix isolation infrared spectroscopy and computational chemistry. Hydrogenated aromatic radicals are thought to be important intermediates in different chemical processes such as pyrolysis, combustion, hydrogenation, and hydrogenolysis. Complete understanding of the nature of these species as possible intermediates in various important chemical processes remains elusive because of the scarcity of the experimental infrared spectra and formation kinetics data of the hydrogenated radicals at low temperatures. Professor Amicangelo and his students will utilize a microwave discharge source with an appropriate precursor molecule and co-deposit the hydrogen atoms with the ring molecules in argon matrices to obtain the infrared spectra of the hydrogenated radicals and conduct the kinetic studies. Their studies could extend the number of hydrogenated radicals characterized by infrared spectroscopy and provide new low temperature data on their formation kinetics. The Amicangelo research group will also engage in an outreach component to visit high school chemistry classes within the Erie School District with portable scientific devices to help the chemistry teachers give their students access to hands-on, high quality scientific laboratory experiments.This proposal focuses on characterizing the infrared spectra and studying the kinetics of hydrogenated radicals formed by the reaction of hydrogen atoms with monosubstituted benzene rings (C6H5X, X = OCH3, CH3, Cl, CN) using matrix isolation infrared spectroscopy and quantum chemical calculations. Hydrogenated radicals of aromatic rings are thought to be important intermediates in several different important chemical processes, such as pyrolysis, combustion, hydrogenation, and hydrogenolysis. Characterizing the infrared spectra of the hydrogenated radicals will be accomplished by using a microwave discharge source with an appropriate precursor molecule and co-depositing the hydrogen atoms with the ring molecules in 15 K argon matrices. Studying the kinetics of the hydrogenated radicals will involve trapping the hydrogen atoms in the argon matrices at 10 K, followed by monitoring the radical growth kinetics as the hydrogen atoms react with the ring molecules in the argon matrices in the 14 – 20 K temperature range. The IR spectra of these transient intermediates will provide highly valuable windows into the mechanisms of important transformations of aromatic substrates, and as such, will be of broad value to the synthetic, mechanistic and computational chemistry communities.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.