碳化合物的循环添加在Si(100):对于表面循环添加反应的选择性,新的机制和方法
1Contribution from the Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, USA.
Journal of the American Chemical Society
|July 27, 2001
概括
密度函数理论揭示了碳烯化合物在Si(100) 表面上经历循环添加反应. 1,2-Dicarbonyls表现出 [2+2] 和 [4+2] 路径,后者形成了一个新的异质-迪尔斯-阿尔德产物.
科学领域:
- 表面化学 表面化学
- 计算化学的计算化学
- 有机化学 有机化学
背景情况:
- 碳基功能组和pi键在表面表现出循环加法反应.
- 之前的实验证实了Si(100) 上碳酸的 [2+2] 循环添加,激活能量最小.
研究的目的:
- 通过密度函数理论,探索含有碳烯的有机分子在Si(100) 表面的循环添加反应.
- 为了研究超出已建立的 [2+2] 循环加法的替代反应途径的潜力.
主要方法:
- 密度函数理论 (DFT) 的计算被用来建模反应路径.
- 对 [2+2] 和 [4+2] 循环添加物的激活障碍和反应机制的分析.
- 计算结果与现有的实验数据进行比较.
主要成果:
- 计算表明1,2-二碳酸,像醇,可以经历 [4+2] 循环添加,以形成异质-迪尔斯-阿尔德产物.
- 两个 [2+2] 和 [4+2] 路径都以可以忽略的激活障碍进行.
- 氧单双的存在影响了 [4+2] 引导体几何和反应竞争.
结论:
- 碳酸在Si(100) 上的反应性与结合的二烯相似,允许 [2+2] 和 [4+2] 循环添加.
- 提出了一种新的 [4+2] 加法机制,涉及氧单对相互作用,与pi电子系统反应不同.
- 最近对Si(100) 上的1,2-二碳烯的实验发现与拟议的 [4+2] 引证相一致.
相关概念视频
02:50Catalysis
The presence of a catalyst affects the rate of a chemical reaction. A catalyst is a substance that can increase the reaction rate without being consumed during the process. A basic comprehension of a catalysts’ role during chemical reactions can be understood from the concept of reaction mechanisms and energy diagrams.
01:16Cycloaddition Reactions: Overview
Cycloadditions are one of the most valuable and effective synthesis routes to form cyclic compounds. These are concerted pericyclic reactions between two unsaturated compounds resulting in a cyclic product with two new σ bonds formed at the expense of π bonds. The [4 + 2] cycloaddition, known as the Diels–Alder reaction, is the most common. The other example is a [2 + 2] cycloaddition.
01:22Heterogeneous Catalysis
Heterogeneous catalysis involves a catalyst in a different phase from the reactants. It is a process where the catalyst and the reactants are in distinct phases, typically solid and gas or liquid.Most heterogeneous catalysts are metals, metal oxides, or acids. The list includes transition metals like iron (Fe), cobalt (Co), nickel (Ni), palladium (Pd), platinum (Pt), chromium (Cr), manganese (Mn), tungsten (W), silver (Ag), and copper (Cu). These metals possess partially vacant d orbitals that...