シングレットカルベンのような反応性を示すダイルテニウムμ-カルビド複合体
Shin Takemoto1, Jun Ohata, Kento Umetani
1Department of Chemistry, Graduate School of Science, Osaka Prefecture University , Sakai, Osaka 599-8531, Japan.
Journal of the American Chemical Society
|November 4, 2014
まとめ
研究者は,新しいμ-カルビド複合体を合成し,第1の移行金属置換シングレットカルベンを合成しました. このカルベンは,核愛者と電愛者とともに作用し,アンビフィリック反応性を示す.
科学分野:
- 有機金属化学 有機金属化学
- カルベンの化学反応
- 協調化化学について
背景:
- μ-メチリジンの複合体は,μ-カルビド種の前駆体である.
- シングレットカルベンは,多用途の反応性中間物質である.
- カーベンの反応性を理解することは,触媒化にとって極めて重要です.
研究 の 目的:
- 新しいμ-カルビド複合体を合成し,特徴づけること.
- μ-カルビド炭素の電子特性と反応性を調査する.
- カーベンの性質をN-ヘテロサイクルカーベンと比較する.
主な方法:
- カチオンのμ-メチリジンの複合体の低温デプロトネーション.
- エレメンタル硫黄とセレニウムによるトラッピング実験.
- (13) C NMRを用いたスペクトロスコーピカル特徴付け.
- 密度関数理論 (DFT) による計算.
主要な成果:
- 熱的に不安定なμ-カルビド複合体[Cp*Ru]2[μ-NPh][μ-C]が成功して合成されました.
- μ-カルビド炭素は,様々な基質 (CO2,Ph2S(+) CH2(-),EtOH,C-H結合) に対して両性反応を示した.
- DFTの研究は,ルテニウム置換物がカルベン中心に強いs-ドナーと弱いπ-ドナーであることを示しました.
結論:
- 合成された複合体は,最初の移行金属で置換されたシングレットカルベンを表しています.
- カーベンの両性的な性質は,その多様な反応性によって確認されています.
- ルテニウム置換剤は,N-ヘテロサイクルカルベンのアミノ群と異なる方法でカルベン中心の電子特性に影響します.
関連する概念動画
Carbocations
11.1K
Carbocations are one of the reaction intermediates formed during several nucleophilic substitutions or elimination reactions. A carbocation is an electron-deficient species with the central carbon atom having six electrons and three bonded atoms. The central carbon in a carbocation is sp2 hybridized with trigonal planar geometry. It has an empty p orbital perpendicular to the plane of the structure that can accept electrons. Thus, carbocations act as strong electrophiles and may react with any...
11.1K
Alkenes via Reductive Coupling of Aldehydes or Ketones: McMurry Reaction
1.4K
The radical dimerization of ketones or aldehydes gives vicinal diols through a pinacol coupling reaction. However, the behavior of titanium metals used for the reaction as a source of electrons is unusual. When the reaction is carried out in the presence of titanium, diols can be isolated at low temperatures. Else titanium further reacts with diols, forming alkenes through the McMurry reaction.
1.4K
Radicals: Electronic Structure and Geometry
4.0K
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...
4.0K
Diels–Alder Reaction: Characteristics of Dienes
3.7K
The Diels–Alder reaction brings together a diene and a dienophile to form a six-membered ring. Both components have unique characteristics that influence the rate of the reaction.
Characteristics of the diene
Conformation
The simplest example of a diene is 1,3-butadiene, an acyclic conjugated π system. At room temperature, the molecule exists as a mixture of s-cis and s-trans conformers by virtue of rotation around the carbon–carbon single bond. Although the s-trans isomer is...
Characteristics of the diene
Conformation
The simplest example of a diene is 1,3-butadiene, an acyclic conjugated π system. At room temperature, the molecule exists as a mixture of s-cis and s-trans conformers by virtue of rotation around the carbon–carbon single bond. Although the s-trans isomer is...
3.7K
Radical Reactivity: Overview
2.1K
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...
2.1K
Radical Reactivity: Intramolecular vs Intermolecular
1.4K
Radical reactions can occur either intermolecularly or intramolecularly. In an intermolecular radical reaction, a nucleophilic radical adds to an electrophilic alkene or vice versa. In such reactions, the radical and generally the alkene, which is also called the radical trap, are two different molecules. Additionally, for such intermolecular reactions to occur, the radical trap must be active, present in an excess concentration, and the radical starting material must have a weak...
1.4K


