Theoretical Studies of Main Group Organometallic Chemistry

这项研究得到了NSF理论和计算的支持。 化学计划 将采用改进的计算技术 通用原子分子电子结构系统（GAMESS） 程序. 这包括制定和实施方法， 进行大分子的电子结构计算， 大规模并行计算机和用于处理 溶剂效应 电子结构理论与动力学相结合 对两者都有定性和定量的了解 热力学和动力学性质。 该理论适用于：（a） 主基和主基之间单键和多键的解析 （B）应变环的理论分析， 超价键，和（c）势能面的计算 主族反应机理的研究和预测 有机金属反应 具体反应包括：（a）硅氢化 和偶联反应，（B）单分子分解和异构化， 和（c）多键化合物的反应。 电子结构理论将一个分子，或一个分子组合， 电子和原子核的强相互作用的机械系统。 在 所有的化学行为都可以通过解决量子 这个多粒子系统的力学运动方程， 经验表明，需要非常繁重的计算来实现 对化学性质进行可靠预测所需的准确度 中等大小的分子。 随着现代 超级计算机，特别是大规模并行计算机， 成为理论化学研究的活跃领域。 这个项目是 这样的研究的一个例子。 它强调理论的应用 碳、硅和钛的化合物以及这些化合物的结合 元素到含有过渡金属原子的有机分子，如 铁. 特别感兴趣的是具有不寻常的 化学键结构，例如应变环或双键， C=Si或Si=Si。 详细研究了这种结构的几何形状和能量学， 不寻常的分子有助于我们设计更大的 具有这些相同的键合特征的分子，或者可能形成 通过化学反应，包括拥有它们的瞬时物种。

This research is supported by the NSF theoretical and computational chemisty program. Improved computational techniques will be implemented in the General Atomic and Molecular Electronic Structure System (GAMESS) program. This includes the development and implementation of methods for performing electronic structure computations for large molecules using massively parallel computers, and computational methods for treating solvent effects. Electronic structure theory is combined with dynamics to obtain a qualitative and quantitative understanding of both thermodynamic and kinetic properties. The theory is applied to: (a) the elucidation of single and multiple bonds between main group and transition metals, (b) theoretical analysis of strained rings and hypervalent bonding, and (c) the computation of potential energy surfaces for and the prediction of reaction mechanisms of main group organometallic reactions. Specific reactions include: (a) hydrosilation and coupling reactions, (b) unimolecular decompositions and isomerations, and (c) reactions of multiply bonded compounds. Electronic structure theory treats a molecule, or a molecular assembly, as a mechanical system of strongly interacting electrons and nuclei. In principle, all chemical behavior can be understood by solving the quantum mechanical equations of motion of this many-particle system, but experience shows that very heavy computations are required to achieve the accuracy required to make reliable predictions of the chemical properties of moderately large molecules. With the advent of modern supercomputers, particularly, of massively parallel computers, this has become an active field of theoretical chemical research. This project is an example of such research. It emphasizes the application of the theory to compounds of Carbon, Silicon, and Titanium and the bonding of these elements to organic molecules containing transition-metal atoms such as iron. Of particular i nterest are moderately small molecules with unusual chemical bond structures such as strained rings or double bonds such as C=Si or Si=Si. Detailed study of the geometries and energetics of such unusual molecules contributes to our ability to design much larger molecules which possess these same bonding features or perhaps are formed by chemical reactions involving transient species which possess them.