Gas Phase Ion Reaction Dynamics of Catalytic Systems

我的研究重点是气相离子反应的动力学。我们继续这项工作与质谱，成像光电子光离子符合光谱（iPEPICO）和红外多光子光解离（IRMPD）光谱与统计速率理论和计算化学。我的小组的一个主要重点是开发模型，以提取可靠的能量和熵的气相离子在各种各样的质谱实验的解离。以前，我们一直专注于小的多环芳烃和探索独特的离子化学的原子金属阴离子。这个建议涉及到一个新的重点，在催化感兴趣的离子，特别是在溶液和星际催化感兴趣的有机金属系统的基本性质。 催化体系的内在性质通常难以确定，并且通常不知道实际的关键活性物质。配体结合能、结构重排和中间物种都是理解催化剂如何工作的关键。带电的有机金属离子可以通过其精确的质量、碰撞截面和解离特性来表征，所有这些都可以在我实验室的质谱仪上获得。有机金属离子的解离将作为碰撞能量的函数进行，并且使用实验参数、RRKM理论和作为碰撞能量的函数的内部能量分布来建模所得到的质谱分解图。这产生了解离配体的键强度和反应途径上的熵信息。这项工作是由iPEPICO实验的动力学数据的可用性的帮助。离子结构将使用IRMPD光谱进行探测，以获得气体离子的红外光谱，在法国克利奥自由电子激光器上完成。扩展从这些实验中获得的信息来描述络合离子反应机制，这可以揭示催化活性中间体，只看到有限的应用。这项研究计划将针对各种各样的有机金属物种，最终导致活性，空气和水分敏感催化剂的合成和检查。目前建议的一个目标是开发纳米液滴反应化学电离作为这些催化剂的合成和表征的常规工具。我们已经在实验室中证明，当来自两个电喷雾发射器的微米至纳米尺寸的液滴混合时，可以发生反应，从而允许在液滴的最终去溶剂化之前发生溶液相化学反应。初步实验表明，通过将来自一个喷雾发射器的配体与来自另一个的金属盐混合，可以形成各种各样的有机金属络合物，包括以前未观察到的新物种。

My research focuses on the dynamics of the reactions of gas-phase ions. We pursue this work with mass spectrometry, imaging photoelectron photoion coincidence spectroscopy (iPEPICO) and infrared multiphoton photodissociation (IRMPD) spectroscopy coupled with statistical rate theory and computational chemistry. A principle focus of my group is the development of models to extract reliable energetics and entropics for the dissociation of gas-phase ions in a wide variety of mass spectrometry experiments. Previously we have focused on small polycyclic aromatic hydrocarbons and explored the unique ion chemistry of atomic metal anions. This proposal involves a new focus on the fundamental properties of ions of interest in catalysis, notably organometallic systems of interest in solution and interstellar catalysis. The intrinsic properties of catalytic systems are often difficult to ascertain, and often the actual key, active species is not known. Ligand binding energies, structural rearrangements and intermediate species are all key to understanding how catalysts work. Charged organometallic ions can be characterized by their accurate mass, collision cross-section and dissociation characteristics, all of which are accessible on the mass spectrometry instrumentation in my lab. The dissociation of organometallic ions will be carried out as a function of collision energy, and the resulting mass spectral breakdown diagrams modeled using experimental parameters, RRKM theory and an internal energy distribution that is a function of the collision energy. This yields bond strengths for the dissociating ligands and entropic information on the reaction pathway. This work is aided by the availability of kinetic data from iPEPICO experiments. Ion structure will be probed using IRMPD spectroscopy to obtain the IR spectra of gaseous ions, done at the French CLIO free electron laser. Extending the information obtained from these experiments to describe complex ion reaction mechanisms, which can shed light on catalytically-active intermediates, has only seen limited application. This research program will target a wide variety of organometallic species, leading ultimately to the synthesis and examination of active, air and moisture sensitive catalysts. One goal of the current proposal is to develop nano-droplet reaction chemical ionization as a routine tool for the synthesis and characterization of these catalysts. We have demonstrated in our lab that reactions can take place when the micro- to nano-sized droplets from two electrospray emitters mix, permitting solution-phase chemistry to take place prior to the final desolvation of the droplets. Preliminary experiments have shown that a wide variety of organometallic complexes, including novel species not previously observed, can be formed by mixing a ligand from one spray emitter with a metal salt from the other.