相关实验视频
Updated: May 21, 2025

10:44
Isolating Free Carbenes, their Mixed Dimers and Organic Radicals
Published on: April 19, 2019
10.6K
甲醇基离子体的难以理解的结构和结合
Santiago Gómez1,2, Jhoan Londoño-Restrepo3, Albeiro Restrepo2
1Department of Physics, Chemistry and Biology (IFM), Linköping University, Linköping 58183, Sweden.
The Journal of chemical physics
|March 19, 2025
概括
甲醇基离子由于邻近的超联结而采用同-周平面形状,其O-H键在室温下充当自由旋转器. 这项计算研究解决了其分子几何学,此前未通过电子自旋共振确定.
科学领域:
- 计算化学计算化学
- 物理化学 物理化学
- 分子光谱学 分子光谱学
背景情况:
- 电子自旋共振 (ESR) 表明电子在甲醇基离子中的脱离.
- 准确的分子几何学的实验性确定仍然难以捉摸.
- 对于反应机制研究来说,了解激素阴离子构造是至关重要的.
研究的目的:
- 通过计算来解决甲醇基离子的分子几何.
- 阐明其形状偏好背后的驱动力.
- 为了研究OH键的旋转动力学.
主要方法:
- 高层次的初始计算.
- 有限温度密度函数理论 (FT-DFT).
- 结合集群与单个,双重和三重 (CCSD ((T)) 计算.
主要成果:
- 一个被确定为全球最低值的H-C-O-H债券的同周平面形状.
- 在C-H和O原子轨道间的旁超合解释了形状偏好.
- 低旋转屏障 (≈0.6 kcal/mol) 表示OH键在室温下表现为自由旋转器.
- 观察到适度的多引用特征,氧原子是静态相关性的关键位置.
结论:
- 这项研究通过计算确定了甲醇基离子的几何形状,有利于同-周平的形状.
- 副鼻腔的超合被确定为稳定相互作用.
- 在环境温度下O-H键的自由旋转行为是由其低的旋转屏障解释的.
更多相关视频
相关概念视频
Radicals: Electronic Structure and Geometry
3.8K
This lesson delves into the geometry of a radical, which is influenced by the electronic structure of the molecule. The principle is similar to that of a lone pair, where the unpaired electron influences the geometry at the radical center.
Accordingly, the structure of a trivalent radical lies between the geometries of carbocations and carbanions. An sp2-hybridized carbocation is trigonal planar, while an sp3-hybridized carbanion is trigonal pyramidal. Here, the difference in geometry is...
Accordingly, the structure of a trivalent radical lies between the geometries of carbocations and carbanions. An sp2-hybridized carbocation is trigonal planar, while an sp3-hybridized carbanion is trigonal pyramidal. Here, the difference in geometry is...
3.8K
π Molecular Orbitals of the Allyl Radical
3.3K
Allyl radicals are three-carbon conjugated systems. They are readily formed as intermediates in halogenation reactions of alkenes involving the addition of halogen to the allylic carbon instead of the double bond. As seen in allyl cations and anions, each of the three sp2-hybridized carbon atoms in allyl radicals has an unhybridized p orbital. These orbitals combine to give three ÃÂÃÂ molecular orbitals.
The allyl systems have identical molecular orbitals but differ in the number of...
The allyl systems have identical molecular orbitals but differ in the number of...
3.3K
Radical Formation: Homolysis
3.5K
A bond is formed between two atoms by sharing two electrons. When this bond is broken by supplying sufficient energy, either two electrons can be taken up by one atom forming ions by the cleavage called heterolysis, or the two electrons are shared by two atoms, with one each creating radicals by the cleavage called homolysis.
3.5K
Radical Reactivity: Electrophilic Radicals
1.8K
Radicals adjacent to electron‐withdrawing groups are called electrophilic radicals. These radicals readily react with nucleophilic alkenes. For example, the malonate radical, in which the radical center is flanked by two electron‐withdrawing groups, reacts readily with butyl vinyl ether, which consists of an electron‐donating oxygen substituent. The reaction between electrophilic malonate radical and nucleophilic vinyl ether is favored because the radical has a...
1.8K
π Molecular Orbitals of the Allyl Cation and Anion
4.0K
An allyl group is a three-carbon conjugated system where the spÃÂó-hybridized allylic carbon is bonded to a CH=CH2ÃÂàgroup via a single bond. Allyl anions can be obtained by treating propene with a strong base that can deprotonate methyl groups. Allyl cations are formed as intermediates during substitution reactions involving allylic halides. In both cases, the hybridization of the allylic carbon changes from sp3 to sp2, giving rise to a carbon chain with three...
4.0K
MO Theory and Covalent Bonding
10.2K
The molecular orbital theory describes the distribution of electrons in molecules in a manner similar to the distribution of electrons in atomic orbitals. The region of space in which a valence electron in a molecule is likely to be found is called a molecular orbital. Mathematically, the linear combination of atomic orbitals (LCAO) generates molecular orbitals. Combinations of in-phase atomic orbital wave functions result in regions with a high probability of electron density, while...
10.2K

