Towards Computer-Aided Catalyst Design: Five Effective Core Potential Studies of C-H Activation

这项无机、生物无机和有机金属化学项目的资助支持孟菲斯州立大学化学系Thomas R. Cundari博士关于CH活化的理论工作。Cundari将对影响催化甲烷转化第一步的因素进行五个计算项目。其中三个项目涉及通过多重键合的Ti、Zr和Hf配合物活化甲烷。我们将探讨π键能和极性对CH激活势垒的影响，以及从酰胺到亚胺配体的变化对CH激活势垒的影响。其他项目将研究镧系元素、Sc和Zr的金属-甲基配合物。一些Ir， Re和W化合物的氧化加成和sigma键复分解机制将被模拟。第五个项目涉及亲电Pt（II）和Hg（II）配合物对甲烷活化的分析。在所有情况下，计算结果将与实验结果进行比较。该研究的主要目标是开发可靠的方法来描述d-和f-阻滞化学，并评估金属、活化配体和辅助配体的复杂相互作用如何影响CH活化。有许多催化剂可用于将丰富的甲烷转化为其他有机产品，如甲醇，这是一种可运输的液体燃料。对于任何转化反应，甲烷中的碳氢键必须被破坏或激活，然后反应的其他步骤才能进行。一些涉及甲烷反应的催化剂的实验数据是已知的，但是一个理解催化剂作用的共同框架，它由金属和伴生基团组成，还没有开发出来。通过对这些反应中催化剂的电子结构进行计算研究，Cundari将确定反应中的重要因素，并对反应机理有更广泛的认识。这项研究将有助于开发更具活性和选择性的甲烷或烷烃催化剂。

This grant in the Inorganic, Bioinorganic, and Organometallic Chemistry Program supports the theoretical work of Dr. Thomas R. Cundari of the Chemistry Department, Memphis State University, on CH activation. Cundari will carry out five computational projects on the factors affecting the first step in catalytic methane conversion. Three of the projects involve methane activation by multiply-bonded Ti, Zr, and Hf complexes. The effect of pi-bond energy and polarity on the CH activation barrier will be explored, as well the effect of changing from amide to imide ligands. Other projects will examine metal-methyl complexes of lanthanides, Sc, and Zr. Oxidative addition and sigma-bond metathesis mechanisms for some Ir, Re, and W compounds will be modeled. The fifth project involves analysis of methane activation by electrophilic Pt(II) and Hg(II) complexes. In all cases, the computational results will be compared to experimental findings. The main goals of the study are to develop reliable methods for describing d- and f-block chemistry and to assess how CH activation is affected by the complex interaction of the metal, activating ligands, and ancillary ligands. A number of catalysts are available for the conversion of methane, which is abundant, to other organic products such as methanol, which is a transportable liquid fuel. For any conversion reaction, a carbon-hydrogen (CH) bond in methane has to be broken, or activated, and then other steps in the reaction can take place. Experimental data on a number of catalysts for reactions involving methane are known, but a common framework for understanding the role of the catalyst, which consists of a metal and accompanying groups, has not been developed. By carrying out computational studies on the electronic structure of the catalysts during these reactions, Cundari will identify important factors in the reaction and develop a broader view of the reaction mechanism. The research will aid in the development of more activ e and selective methane or alkane catalysts.