形成一个不寻常的四个成员的环 (tetrazetidine) 基离子
David Camp1, Marc Campitelli, Graeme R Hanson
1Eskitis Institute, Griffith University, Nathan QLD 4111, Australia. david.camp@griffith.edu.au
Journal of the American Chemical Society
|June 20, 2012
概括
研究人员合成了一种稳定的四基四乙丁四碳酸盐基离子,具有新型循环N(4) 环系统. 电子磁共振和DFT计算证实了它的结构和令人惊的寿命.
科学领域:
- 有机化学 有机化学
- 激进化学 激进化学是什么
- 频谱学是一种光谱学.
背景情况:
- 新型环系统的合成和表征在有机化学中至关重要.
- 循环含化合物,特别是那些具有N(4) 系统的化合物,由于其独特的电子性质和潜在的应用,具有显著的兴趣.
- 三obu反应及其变体广泛用于C-O和C-N键形成.
研究的目的:
- 为了合成和表征一种新的四基四泽提丁四碳酸盐基离子.
- 通过光谱和计算方法阐明这种激进物种的结构.
- 为了研究N(4) 环系统的稳定性和反应机制.
主要方法:
- 用二烯亚二碳酸盐对三啡的处理.
- 电子偏磁共振 (EPR) 谱学用于基质特征.
- 密度函数理论 (DFT) 计算用于结构分析和光谱模拟.
主要成果:
- 形成一个对称的四基四乙丁四碳酸盐基离子与循环N(4) 环.
- EPR光谱学揭示了9线的光谱,表明有四个磁性相当的原子和四个甲质子.
- DFT计算和光谱模拟证实了基离子结构和稍微的N(4) 环形状.
- 激进物种表现出了显著的稳定性,在室温下持续数小时.
结论:
- 这项研究成功地合成和表征了一种新的N(4) 循环基离子.
- 这些发现提供了关于四二衍生物的形成和稳定性的见解.
- 对于观察到的转换,提出了一个可能与Rauhut-Currier或Morita-Baylis-Hillman反应相关的激进机制.
相关概念视频
Aromatic Hydrocarbon Cations: Structural Overview
Cycloheptatriene is a neutral monocyclic unsaturated hydrocarbon that consists of an odd number of carbon atoms and an intervening sp3 carbon in the ring. The three double bonds in the ring correspond to 6 π electrons, which is a Huckel number, and therefore satisfies the criteria of 4n + 2 π electrons. However, the intervening sp3 carbon disrupts the continuous overlap of p orbitals. As a result, cycloheptatriene is not aromatic.
Removing one hydrogen from the intervening CH2 group with both...
Removing one hydrogen from the intervening CH2 group with both...
Radicals: Electronic Structure and Geometry
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...
Aromatic Hydrocarbon Anions: Structural Overview
Neutral hydrocarbons like cyclopentadiene with an odd number of carbon atoms and one intervening CH2 group in the ring are not aromatic. Cyclopentadiene with 4 π electrons does not satisfy the 4n + 2 π electron rule. Additionally, the intervening CH2 group is sp3 hybridized and lacks a vacant p orbital, thereby interrupting the overlap of p orbitals in a continuous manner and preventing the delocalization of π electrons throughout the ring.
Due to the absence of continuous overlap of p...
Due to the absence of continuous overlap of p...
Radical Formation: Addition
Radicals can be formed by adding a radical to a spin-paired molecule. This is typically observed with unsaturated species, where the addition of a radical across the π bond leads to the production of a new radical by dissolving the π bond. For example, the addition of a Br radical to an alkene yields a carbon-centered radical.
Similar to charge conservation in chemical reactions, spin conservation is implicit for radical reactions. Accordingly, the product formed must possess an unpaired...
Similar to charge conservation in chemical reactions, spin conservation is implicit for radical reactions. Accordingly, the product formed must possess an unpaired...
Radical Formation: Overview
A bond can be broken either by heterolytic bond cleavage to form ions or homolytic bond cleavage to yield radicals. A fishhook arrow is used to represent the motion of a single electron in homolytic bond cleavage. There are two main sources from which radicals can be formed:
Radicals from spin-paired molecules:
Radicals can be obtained from spin-paired molecules either by homolysis or electron transfer. While two radicals are formed in the former, an electron is added in the latter, also known...
Radicals from spin-paired molecules:
Radicals can be obtained from spin-paired molecules either by homolysis or electron transfer. While two radicals are formed in the former, an electron is added in the latter, also known...
Radical Reactivity: Overview
Radicals, the highly reactive species, gain stability by undergoing three different reactions. The first reaction involves a radical-radical coupling, in which a radical combines with another radical, forming a spin‐paired molecule. The second reaction is between a radical and a spin‐paired molecule, generating a new radical and a new spin‐paired molecule. The third reaction is radical decomposition in a unimolecular reaction, forming a new radical and a spin‐paired molecule. These three...


