[N-I-N](+) ハロゲン結合に対する代替効果
Anna-Carin C Carlsson1, Krenare Mehmeti1, Martin Uhrbom1
1Department of Chemistry and Molecular Biology, University of Gothenburg , SE-412 96 Gothenburg, Sweden.
Journal of the American Chemical Society
|June 7, 2016
まとめ
電子密度は[N-I-N](+) ハロゲン結合の安定性に大きく影響し,より高い電子密度は安定性を高める. この発見は[bis ((ピリジン)) ハロゲン (((+)) タイプの合成反応剤の反応性を制御する上で極めて重要です.
科学分野:
- 超分子化学
- ハロゲン結合
- 有機合成
背景:
- [N-I-N](+) ハロゲン結合は,様々な化学系における重要な相互作用である.
- ハロゲン結合に対する電子効果を理解することは,合成反応剤の設計に不可欠です.
研究 の 目的:
- 電子密度が[N-I-N](+) ハロゲン結合にどのように影響するか調べる.
- 置換剤効果とハロゲン結合の関係を探求する.
主な方法:
- 置換された[ビス・ピリジン・ヨウ素]と関連複合体の合成.
- (15) NMRとUV運動を含むスペクトロスコピー研究.
- 計算方法 (DFT) と単結晶X線微分法
主要な成果:
- ピリジンの窒素電子密度の系統的変動は,15N NMRと計算分析によって確認された.
- [N-I-N](+) ハロゲン結合の形成は,重要な (15) N NMR 調整シフトをもたらした.
- ハロゲン結合受容体の電子密度の増加は[N·I·N](+) 結合を安定させ,電子欠乏は安定性を低下させる.
結論:
- [N-I-N](+) ハロゲン結合は,電子密度に関係なく静的で対称である.
- 電子密度は主にハロゲン結合の安定性に影響し,N-I結合の長さに影響しない.
- 電子密度調節は[bis ((ピリジン)) ハロゲン)) タイプの反応剤の反応性を制御するための方法を提供します.
さらに関連する動画
09:37Imine Metathesis by Silica-Supported Catalysts Using the Methodology of Surface Organometallic Chemistry
Published on: October 18, 2019
10.2K
![The Synthesis of [Sn10SiSiMe334]2- Using a Metastable SnI Halide Solution Synthesized via a Co-condensation Technique](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F54498.jpg&w=3840&q=50)
12:43The Synthesis of [Sn10SiSiMe334]2- Using a Metastable SnI Halide Solution Synthesized via a Co-condensation Technique
Published on: November 28, 2016
9.1K
関連する概念動画
02:45Alkyl Halides
21.2K
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...
21.2K
02:27Predicting Products: SN1 vs. SN2
17.7K
Nucleophilic substitution reactions of alkyl halides can proceed via an SN1 or an SN2 mechanism. While in SN2 reactions, the nucleophile attacks the substrate simultaneously as the leaving group departs, in SN1 reactions, the substrate first dissociates to give the carbocation intermediate. Various factors such as the structure of the substrate, the strength of the nucleophile, and the nature of the solvent promote one mechanism over the other.
With increased substitution on the alkyl halide,...
With increased substitution on the alkyl halide,...
17.7K
02:26SN2 Reaction: Transition State
12.6K
An SN2 reaction of an alkyl halide is a single-step process in which bond formation between the nucleophile and the substrate and bond breaking between the substrate and the halide occurs simultaneously through a transition state without forming an intermediate.
When the nucleophile approaches the electrophilic carbon with its lone pairs, the halide acts as a leaving group and moves away with the electron-pair bonded to the carbon. Dotted partial bonds represent the bonds being formed or broken...
When the nucleophile approaches the electrophilic carbon with its lone pairs, the halide acts as a leaving group and moves away with the electron-pair bonded to the carbon. Dotted partial bonds represent the bonds being formed or broken...
12.6K
02:38Electrophilic Addition to Alkynes: Halogenation
10.4K
Introduction
Halogenation is another class of electrophilic addition reactions where a halogen molecule gets added across a π bond. In alkynes, the presence of two π bonds allows for the addition of two equivalents of halogens (bromine or chlorine). The addition of the first halogen molecule forms a trans-dihaloalkene as the major product and the cis isomer as the minor product. Subsequent addition of the second equivalent yields the tetrahalide.
Halogenation is another class of electrophilic addition reactions where a halogen molecule gets added across a π bond. In alkynes, the presence of two π bonds allows for the addition of two equivalents of halogens (bromine or chlorine). The addition of the first halogen molecule forms a trans-dihaloalkene as the major product and the cis isomer as the minor product. Subsequent addition of the second equivalent yields the tetrahalide.
10.4K
02:52Predicting Products: Substitution vs. Elimination
15.1K
When a nucleophile and an alkyl halide react, nucleophilic substitution and β-elimination reactions compete to generate products.
The following factors can influence the mechanisms competing against each other:
The following factors can influence the mechanisms competing against each other:
15.1K
02:25SN1 Reaction: Mechanism
15.2K
Kinetic studies of ionization of a tertiary halide in a protic solvent suggest that only the substrate participates in the rate-determining step (slow step). The nucleophile is involved only after the slowest step. The SN1 reaction takes place in a multiple-step mechanism.
Firstly, the haloalkane ionizes to generate a carbocation intermediate and a halide ion. This heterolytic cleavage is highly endothermic with large activation energy. The ionization of the substrate, facilitated by a...
Firstly, the haloalkane ionizes to generate a carbocation intermediate and a halide ion. This heterolytic cleavage is highly endothermic with large activation energy. The ionization of the substrate, facilitated by a...
15.2K