相关实验视频
Updated: Jan 30, 2026

10:44
Isolating Free Carbenes, their Mixed Dimers and Organic Radicals
Published on: April 19, 2019
11.6K
通过周期性氨基基稳定过渡性氨基基的分离
Mujahuddin M Siddiqui1, Samir Kumar Sarkar1, Soumen Sinhababu1
1Institut für Anorganische Chemie , Universität Göttingen , Tammannstrasse 4 , 37077 , Göttingen , Germany.
Journal of the American Chemical Society
|January 12, 2019
概括
研究人员合成并表征了新的非循环中性 (I) 基,克服了之前的合成挑战. 这些稳定的基代表了主要组元素化学的重大进步.
科学领域:
- 有机金属化学
- 主组元素化学
- 根本性的稳定
背景情况:
- 主群激素,特别是和的激素,由于它们对二元化的高度易感,因此难以分离.
- 虽然N-异环碳 (NHCs) 和循环氨基碳 (cAACs) 在稳定主要基群方面表现出成功,但基仍然难以捉摸.
- 之前的合成努力受到这些物种固有的反应性和短暂性质的影响.
研究的目的:
- 报告新型非循环中性基的成功合成和分离.
- 用实验和理论方法结合使用这些基的特征.
- 研究合成的 (I) 化合物的结构和结合特性.
主要方法:
- 通过在循环氨基基 (cAAC) 的存在下与KC8减少[SiR3]NGeCl3]基的I基合成.
- 描述技术包括单晶X射线结构分析,循环电压测量和电子磁共振 (EPR) 光谱.
- 使用理论方法分析结构和结合的计算调查.
主要成果:
- 成功合成了两个不同的非循环中性 (I) 基:Cy-cAAC:GeN(SiMe3) DIP (1) 和Me-cAAC:GeN(SiPh3) Mes (2).
- 综合性表征证实了这些基物种的稳定存在.
- 通过X射线衍射,电化学,EPR和理论计算获得的详细结构和电子洞察.
结论:
- 一个可行的合成途径的开发使得以前无法获得的非循环中性 (I) 基的分离成为可能.
- 通过cAAC配体实现的稳定对于防止二分化和分离这些反应性物种至关重要.
- 这项工作显著推进了主要基团化学领域,为基于的化合物开辟了新的途径.
相关概念视频
Amino acids
105.3K
Amino acids are the monomers that comprise proteins. Each amino acid has the same fundamental structure, which consists of a central carbon atom, or the alpha (α) carbon, bonded to an amino group (NH2), a carboxyl group (COOH), and to a hydrogen atom. Every amino acid also has another atom or group of atoms bonded to the central atom known as the R group. There are 20 common amino acids present in proteins, each with a different R group. Variation in the amino acid sequence is responsible for...
105.3K
Radical Substitution: Halogenation of Alkanes and Alkyl Substituents
10.1K
In the presence of heat or light, alkanes react with molecular halogens to form alkyl halides by a substitution reaction called radical halogenation. This reaction has three steps: initiation, propagation, and termination, as seen in the radical chlorination of methane to produce methyl chloride.
In the initiation step of the reaction, the chlorine molecule undergoes homolytic cleavage in the presence of light or heat, forming two highly reactive chlorine radicals. Propagation occurs in two...
In the initiation step of the reaction, the chlorine molecule undergoes homolytic cleavage in the presence of light or heat, forming two highly reactive chlorine radicals. Propagation occurs in two...
10.1K
Radical Substitution: Hydrogenolysis of Alkyl Halides with Tributyltin Hydride
2.3K
Radical substitution reactions can be used to remove functional groups from molecules. The hydrogenolysis of alkyl halides is one such reaction, where the weak Sn–H bond in tributyltin hydride reacts with alkyl halides to form alkanes. Here, the reagent Bu3SnH yields tributyltin halide as a byproduct.
The bonds formed in this reaction are stronger than the bonds broken, making it energetically favorable. The reaction follows a radical chain mechanism similar to radical halogenation reactions,...
The bonds formed in this reaction are stronger than the bonds broken, making it energetically favorable. The reaction follows a radical chain mechanism similar to radical halogenation reactions,...
2.3K
Cyclic Processes And Isolated Systems
3.5K
A thermodynamic system with zero heat exchange and work is an isolated system. For these systems, the internal energy remains constant.
In the case of a non-isolated system, the change in the internal energy is zero only if the process is cyclic. A thermodynamic process is considered cyclic if the system undergoes a series of changes and returns to its initial state.
Consider a cyclic process that returns to its initial state, undergoing a four-step process. The heat transfer along each...
In the case of a non-isolated system, the change in the internal energy is zero only if the process is cyclic. A thermodynamic process is considered cyclic if the system undergoes a series of changes and returns to its initial state.
Consider a cyclic process that returns to its initial state, undergoing a four-step process. The heat transfer along each...
3.5K
Alkyl Halides
19.9K
Structural Properties
Alkyl halides are halogen-substituted alkanes wherein one or more hydrogen atoms of an alkane is replaced by a halogen atom such as fluorine, chlorine, bromine, or iodine. The carbon atom in an alkyl halide is bonded to the halogen atom, which is sp3-hybridized and exhibits a tetrahedral shape.
Unlike alkyl halides, compounds in which a halogen atom is bonded to an sp2 -hybridized carbon atom of a carbon-carbon double bond (C=C) are called vinyl halides. Whereas aryl...
Alkyl halides are halogen-substituted alkanes wherein one or more hydrogen atoms of an alkane is replaced by a halogen atom such as fluorine, chlorine, bromine, or iodine. The carbon atom in an alkyl halide is bonded to the halogen atom, which is sp3-hybridized and exhibits a tetrahedral shape.
Unlike alkyl halides, compounds in which a halogen atom is bonded to an sp2 -hybridized carbon atom of a carbon-carbon double bond (C=C) are called vinyl halides. Whereas aryl...
19.9K
Nuclear Stability
23.2K
Protons and neutrons, collectively called nucleons, are packed together tightly in a nucleus. With a radius of about 10−15 meters, a nucleus is quite small compared to the radius of the entire atom, which is about 10−10 meters. Nuclei are extremely dense compared to bulk matter, averaging 1.8 × 1014 grams per cubic centimeter. If the earth’s density were equal to the average nuclear density, the earth’s radius would be only about 200 meters.
To hold positively charged protons together...
To hold positively charged protons together...
23.2K

