稳定性和动态过程在16VE化 (III) 乙烯和 (I) σ-乙复合物中:实验和计算研究
Marc D Walter1, Peter S White, Cynthia K Schauer
1Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599-3290, United States.
Journal of the American Chemical Society
|September 24, 2013
概括
本研究详细介绍了和乙烯复合物的制备和表征. 研究人员研究了联体交换通路,揭示了和在链路反应中的独特机制.
科学领域:
- 有机金属化学 有机金属化学
- 催化剂是一种催化剂.
- 反应机制 反应机制
背景情况:
- ) 和) 乙烯复合体 (PONOP) M (C2H5) 的制备,以及) 复合体 (PONOP) Ir (C3H7).
- 复合物的质子化产生化, (PONOP) (H) (R),用于机械学研究.
研究的目的:
- 为了研究和的化复合物的动力学.
- 阐明联体交换的机制,包括"链路"和分解途径.
- 为了比较和复合体之间的反应性和机械路径.
主要方法:
- 合成 () 和 () 的乙烯和复合物.
- 低温质子化形成基化物中间体.
- 动态核磁共振 (NMR) 光谱 (1H和13C) 用于研究位点交换和障碍物.
- 密度函数理论 (DFT) 计算以评估协调模式和交换路径.
主要成果:
- 和乙烯/复合体及其质子化化形式的表征.
- 在复合体中量化质子化物交换,乙损失和"链路行走"的激活障碍.
- 与相比,在复合体中确定较低的乙损失和"链路行走"障碍.
- 对中的 η2-乙中间体和中的对称乙烯二化物中间体的光谱证据.
结论:
- 和复合体表现出不同的联体交换和分解机制.
- DFT研究支持Rh (η2-乙) 与Ir (乙烯二化物) 中"链路行走"的不同最低能量的途径.
- 这项研究提供了对过渡金属基复合物的基本反应性的关键见解.
更多相关视频
相关概念视频
Radical Reactivity: Steric Effects
The presence of electron-donating, electron-withdrawing, or conjugating groups adjacent to a radical center, imparts electronic stabilization to the radicals. Examples of such electronically-stabilized radicals are triphenylmethyl, tetramethylpiperidine‐N‐oxide, and 2,2‐diphenyl‐1‐picrylhydrazyl. These radicals are remarkably stable and are known as persistent radicals. Some of the persistent radicals can even be isolated and purified.
Along with electronic factors, steric factors also account...
Along with electronic factors, steric factors also account...
Stability of Conjugated Dienes
Introduction
A comparison of the enthalpies of hydrogenation of dienes reveals that conjugated dienes release less heat on hydrogenation, rendering them more stable than their nonconjugated analogs.
A comparison of the enthalpies of hydrogenation of dienes reveals that conjugated dienes release less heat on hydrogenation, rendering them more stable than their nonconjugated analogs.
Molecular Orbital Theory II
Molecular Orbital Energy Diagrams
π Molecular Orbitals of 1,3-Butadiene
Conjugated dienes have lower heats of hydrogenation than cumulated and isolated dienes, making them more stable. The enhanced stabilization of conjugated systems can be understood from their π molecular orbitals.
The simplest conjugated diene is 1,3-butadiene: a four-carbon system where each carbon is sp2-hybridized and has an unhybridized p orbital that contains an unpaired electron. According to molecular orbital theory, atomic orbitals combine to form molecular orbitals such that the number...
The simplest conjugated diene is 1,3-butadiene: a four-carbon system where each carbon is sp2-hybridized and has an unhybridized p orbital that contains an unpaired electron. According to molecular orbital theory, atomic orbitals combine to form molecular orbitals such that the number...
Stability of Substituted Cyclohexanes
This lesson discusses the stability of substituted cyclohexanes with a focus on energies of various conformers and the effect of 1,3-diaxial interactions.
The two chair conformations of cyclohexanes undergo rapid interconversion at room temperature. Both forms have identical energies and stabilities, each comprising equal amounts of the equilibrium mixture. Replacing a hydrogen atom with a functional group makes the two conformations energetically non-equivalent.
For example, in...
The two chair conformations of cyclohexanes undergo rapid interconversion at room temperature. Both forms have identical energies and stabilities, each comprising equal amounts of the equilibrium mixture. Replacing a hydrogen atom with a functional group makes the two conformations energetically non-equivalent.
For example, in...
Hybridization of Atomic Orbitals II
sp3d and sp3d 2 Hybridization


