Spectroscopy and Photodissociation Dynamics Imaging of C-C and C-H Bond Activation by Transition Metal and Metal Oxide Cations

过渡金属和金属氧化物阳离子激活 C-C 和 C-H 键的光谱学和光解离动力学成像

• 批准号: 0911225
• 负责人: Ricardo Metz
• 金额: $ 45万
• 依托单位: University of Massachusetts Amherst
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-15 至 2013-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0911225&HistoricalAwards=false
• 关键词: Spectroscopy; Photodissociation; Dynamics; Imaging; Bond

The Experimental Physical Chemistry Program of the Division of Chemistry supports the research of Professor Ricardo Metz and his students at the University of Massachusetts, Amherst. Professor Metz will study the spectroscopy and photodissociation dynamics of the reactants and intermediates of reactions in which C-C and C-H bonds are activated by transition metal and metal oxide cations. As a reaction proceeds from reactants to products, it forms several intermediates (e.g., entrance channel complexes, insertion intermediates, and exit channel complexes). By studying the structure and bonding of these intermediates, Metz and his students will be able to characterize the detailed mechanism for the reaction. Vibrational spectroscopy will be used to study bonding in the ground electronic states of the ions. A novel photofragment imaging instrument will be constructed to study ion photodissociation dynamics following electronic excitation, measuring kinetic energy release and fragment anisotropy. This will determine precise bond strengths and is a detailed probe of excited state dynamics and the couplings between excited electronic states. Reactions to be studied include the conversion of methane to larger hydrocarbons by metal atoms and clusters and methane to methanol and benzene to phenol conversion by metal oxides. Photoionization studies of neutral metal oxides and metal carbenes carried out at the Advanced Light Source, Lawrence Berkeley National Laboratory, will measure ionization energies and neutral bond strengths. Extensive electronic structure calculations will complement the experiments.Improved catalysts are needed to make optimal use of limited energy resources, and fundamental studies of C-H and C-C bond activation aid in this effort by expanding our understanding of the mechanisms of metal-based catalysis. The project also provides graduate students and postdoctoral researchers with extensive training in experimental and computational physical chemistry.

化学系的实验物理化学项目支持阿默斯特马萨诸塞州大学的里卡多梅斯教授和他的学生的研究。 教授梅斯将研究光谱和光解动力学的反应物和中间体的反应，其中C-C和C-H键被激活的过渡金属和金属氧化物阳离子。当反应从反应物进行到产物时，它形成几种中间体（例如，入口通道复合物、插入中间体和出口通道复合物）。通过研究这些中间体的结构和键合，梅斯和他的学生将能够描述反应的详细机理。振动光谱学将用于研究离子基态电子态的成键。 将建立一种新型的光碎片成像仪，用于研究电子激发后离子的光解离动力学，测量动能释放和碎片各向异性。 这将确定精确的键强度，是激发态动力学和激发电子态之间的耦合的详细探测。待研究的反应包括通过金属原子和簇将甲烷转化为较大的烃，以及通过金属氧化物将甲烷转化为甲醇和苯转化为苯酚。在劳伦斯伯克利国家实验室的先进光源进行的中性金属氧化物和金属卡宾的光电离研究将测量电离能和中性键强度。 大量的电子结构计算将补充实验。需要改进催化剂以最佳利用有限的能源，而C-H和C-C键活化的基础研究通过扩展我们对金属基催化机制的理解来帮助我们实现这一目标。该项目还为研究生和博士后研究人员提供实验和计算物理化学方面的广泛培训。