Photoionization and Photoelectron Spectroscopy of Transient Organometallic Complexes

饱和烃或烷烃构成有机化学品的最丰富的原料。控制碳氢化合物中的哪些键与其他分子反应（也称为“选择性活化和功能化”）仍然是化学科学的重大挑战之一。在这个由化学系化学结构、动力学和机制A（CSDM-A）项目资助的项目中，肯塔基州大学的杨东升教授通过研究金属原子与碳氢化合物的相互作用方式，并使用实验室自制的仪器和先进的激光光谱技术检测这些反应中的活性化学物质，为这项任务做出了贡献。杨教授的研究显示了碳氢化合物如何被金属激活并转化为其他化学物质。这项工作提高了对金属催化剂如何提高化学反应速率和降低烃转化所需能量的基本理解。该项目为不同层次的学生提供具有技术挑战性的培训，并为他们在工业，学术界或公共部门的职业生涯做好准备。该项目侧重于金属介导的烷烃活化反应中形成的瞬态有机金属络合物的光谱表征。重点放在小烷烃的C-H和C-C键活化和镧系金属对烷基腈、胺和醇的远程官能化。预期的结果是准确的电离能，金属配体和配体为基础的振动频率，电子状态，自旋轨道分裂，和短寿命物种的分子结构。计划是研究镧系元素的电子构型效应和直链、支链和环状烷烃及官能化烷烃衍生物的反应性-结构关系。实验方法包括激光辅助分子束反应;飞行时间质谱;质量分析阈值电离，零电子动能，红外-紫外光电离光谱;和慢电子速度图成像。实验测量与量子化学计算相补充。参与该项目的学生不仅接受上述实验技术的培训，而且还接受量子化学计算，即密度泛函理论，以及通过与其他专家（例如，Michael施密特教授，爱荷华州）。该奖项反映了NSF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。

Saturated hydrocarbons or alkanes constitute the most abundant feedstock for organic chemicals. Controlling which bonds in hydrocarbons react with other molecules (also known as "selective activation and functionalization") remains one of the grand challenges in the chemical sciences. In this project funded by the Chemical Structure, Dynamics and Mechanisms A (CSDM-A) Program of the Chemistry Division, Professor Dong-Sheng Yang of the University of Kentucky contributes to this task by examining the way metal atoms interact with the hydrocarbon compounds and detecting reactive chemical species in these reactions using laboratory-made instruments and sophisticated laser spectroscopic techniques. Professor Yang-s research shows how the hydrocarbons are activated by metals and converted into other chemicals. This work improves the fundamental understanding about how metal catalysts increase the rate of a chemical reaction and reduce the energy required for hydrocarbon conversion. The project provides technically challenging training for a diverse group of students at all levels and prepares them for careers in industry, academia, or the public sector.The projects focuses on spectroscopic characterization of transient organometallic complexes formed in metal-mediated alkane activation reactions. Emphasis is placed on the C-H and C-C bond activation of small alkanes and the remote functionalization of alkyl nitriles, amines, and alcohols by lanthanide metals. Expected results are the accurate ionization energies, metal-ligand and ligand-based vibrational frequencies, electronic states, spin-orbit splitting, and molecular structures of the short-lived species. The plan is to examine the electron configuration effects of the lanthanide elements and the reactivity-structural relationships of the linear, branched, and cyclic alkanes and functionalized alkane derivatives. Experimental methods include laser-assisted molecular beam reactions; time-of-flight mass spectrometry; mass-analyzed threshold ionization, zero electron kinetic energy, and infrared-ultraviolet photoionization spectroscopy; and slow electron velocity-map imaging. The experimental measurements are supplemented with quantum chemical calculations. The students engaged in this project are being trained not only in the aforementioned experimental techniques, but also quantum chemistry calculations, namely density functional theory, as well as other advanced tools through collaboration with other experts (e.g., Prof. Michael Schmidt, Iowa State).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.