Theoretical Studies of Main Group Organometallic Chemistry

理论和计算化学项目正在支持爱荷华州立大学的马克·戈登教授。将开展的研究将是量子化学和相关领域的理论和代码开发的结合，以及现代量子化学在主族有机金属化学问题上的应用。理论上的新进展将集中在两个方面：(1)将有效的片断方法扩展到任何溶剂、激发态，并包括更高级别的分子间相互作用；(2)扩展量子化学和动力学之间的界面，以便于研究液体动力学和溶剂化动力学。其中一个关键的应用领域与这些新的理论发展相联系，即有机金属化学中溶剂化对机理的影响的研究。在许多感兴趣的机理中，包括环状有机硅化合物的开环性质，催化剂对氢化硅化和双硅化反应的影响，以及有机金属偶联反应的性质。其他应用包括钛和其他IVB族元素的化学的广泛研究，以及主要基团-过渡金属键的热化学的定量研究。虽然大多数化学反应是在溶剂存在的情况下进行的，但直到最近，绝大多数的理论研究都是在孤立的分子上进行的。即使是现在，大多数包括溶剂影响的现有模型也不能明确地处理单个溶剂分子，因此不能确定感兴趣的化学体系和溶剂之间相互作用的性质。Gordon小组发展了一种新的溶剂模型--有效碎片势模型，旨在显式处理溶剂分子。目前，这一模型仅限于最普遍的溶剂-水。这个模型现在将被扩展，以便可以访问在有机金属化学中感兴趣的任何溶剂。这一新方法将用于研究溶剂化对几个重要化学反应的影响。预计这些研究将为这些反应如何发生提供一些基本的理解，并最终为新产品的设计提供一些指导。

The Theoretical and Computational Chemistry Program is supporting Prof. Mark Gordon of Iowa State University. The research to be performed will be a combination of theory and code development in quantum chemistry and related areas and applications of modern quantum chemistry to problems in main group organometallic chemistry. The new developments in theory will focus on two areas: (1) an extension of the effective fragment method for solvation to any solvent, to excited states, and to include higher-order intermolecular interactions, and (2) to extend the interface between quantum chemistry and dynamics to facilitate the study of dynamics of liquids and solvation dynamics. One of the key applications areas interfaces with these new theory developments, namely the study of the influence of solvation on mechanisms in organometallic chemistry. Among the many mechanisms of interest are the nature of the ring opening in cyclic organosilicon compounds, the effect of catalysts on reactions such as the hydrosilation and bis-silylation reactions, and the nature of the organometallic coupling reaction. Other applications include a broad-based study of the chemistry of titanium and other Group IVB elements, and quantitative studies of the thermochemistry of main group- transition metal bonding. Although most chemical reactions occur in the presence of a solvent, until very recently, the vast majority of theoretical studies have been carried out on isolated molecules. Even now, most current models that include the effects of solvents do not explicitly treat the individual solvent molecules and therefore cannot determine the nature of the interactions between the chemical system of interest and the solvent. The Gordon group has developed a new solvent model, the effective fragment potential model, that is designed to treat the solvent molecules explicitly. Currently, this model is limited to the most ubiquitous solvent, water. This model will now be extended so that any solvent of interest in organometallic chemistry will be accessible. The new method will be applied to study the effects of solvation on several important chemical reactions. It is anticipated that these studies will provide some fundamental understanding of how these reactions occur and ultimately provide some guidance on the design of new products.