"触媒性ニトロシル効果"は,NOの屈曲により,レニウムベースのアルケンの水素化の効率が向上する
Yanfeng Jiang1, Birgitta Schirmer, Olivier Blacque
1Anorganisch-Chemisches Institut, Universität Zürich, Winterthurerstrasse 190, CH-8037, Zürich, Switzerland.
Journal of the American Chemical Society
|February 7, 2013
まとめ
新しいレニウム ((I)) 複合体は,アルケンの水素化を高活性と長寿命で触媒化する. 機械学的研究は,シリリウム活性化,ニトロシル曲折,および二機能的なH2添加を含む新しいオズボーン型サイクルを明らかにし,超電気的レニウムセンターにつながる.
科学分野:
- 有機金属化学 有機金属化学
- カタリシス カタリシス カタリシス
- 水素化反応は,水素化反応による.
背景:
- レーニウム ((I)) 複合体は,触媒的応用のために探求されています.
- アルケンの水素化のための効率的で安定した触媒の開発は,有機合成において極めて重要です.
研究 の 目的:
- 新規のダイオド・レニウム ((I)) 複合体を合成し,特徴づけること.
- アルケンの水素化における彼らの触媒性能を調査するために.
- 総合的な研究を用いて反応機構を解明する.
主な方法:
- ディオド・レニウム ((I)) 複合体の合成と特徴付け.
- 端末アルケンと内部アルケンの触媒性水素化は,ヒドロシラン/B(C6F5) 3共触媒を用いて行われます.
- 運動イソトープ効果,H2/D2スクランブル,VT NMR,DFT計算を含むメカニズム研究.
主要な成果:
- 準備されたレニウム (((I) 複合体は,アルケンの水素化で優れた活性と長寿を示します.
- 機械学的研究は,速度を決定する還元性除去によるオズボーン型水素化サイクルを示している.
- アクティベーションには,シリリウムカチオン調整,ニトロシル曲折,異解性H-H分裂,およびフォスフィンリガンドプロトネーションが関与し,触媒の空白部位を生成します.
結論:
- 新型レニウム (((I) コンプレックスは,非常に効果的な水素化触媒である.
- 提案されたメカニズムは,活性で超電性レニウムセンターを生成するニトロシル曲折とフォスフィン損失の役割を強調しています.
- この研究は,水素化のための高度な有機金属触媒の設計に関する洞察を提供します.
さらに関連する動画
関連する概念動画
02:17Reduction of Alkenes: Asymmetric Catalytic Hydrogenation
Catalytic hydrogenation of alkenes is a transition-metal catalyzed reduction of the double bond using molecular hydrogen to give alkanes. The mode of hydrogen addition follows syn stereochemistry.
The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...
The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...
02:13Reduction of Alkenes: Catalytic Hydrogenation
Alkenes undergo reduction by the addition of molecular hydrogen to give alkanes. Because the process generally occurs in the presence of a transition-metal catalyst, the reaction is called catalytic hydrogenation.
Metals like palladium, platinum, and nickel are commonly used in their solid forms — fine powder on an inert surface. As these catalysts remain insoluble in the reaction mixture, they are referred to as heterogeneous catalysts.
The hydrogenation process takes place on the surface of...
Metals like palladium, platinum, and nickel are commonly used in their solid forms — fine powder on an inert surface. As these catalysts remain insoluble in the reaction mixture, they are referred to as heterogeneous catalysts.
The hydrogenation process takes place on the surface of...
02:24Reduction of Alkynes to cis-Alkenes: Catalytic Hydrogenation
Introduction
Like alkenes, alkynes can be reduced to alkanes in the presence of transition metal catalysts such as Pt, Pd, or Ni. The reaction involves two sequential syn additions of hydrogen via a cis-alkene intermediate.
Like alkenes, alkynes can be reduced to alkanes in the presence of transition metal catalysts such as Pt, Pd, or Ni. The reaction involves two sequential syn additions of hydrogen via a cis-alkene intermediate.
01:28Reduction of Benzene to Cyclohexane: Catalytic Hydrogenation
Unlike the easy catalytic hydrogenation of an alkene double bond, hydrogenation of a benzene double bond under similar reaction conditions does not take place easily. For example, in the reduction of stilbene, the benzene ring remains unaffected while the alkene bond gets reduced. Hydrogenation of an alkene double bond is exothermic and a favorable process. In contrast, to hydrogenate the first unsaturated bond of benzene, an energy input is needed; that is, the process is endothermic. This is...
01:25Radical Anti-Markovnikov Addition to Alkenes: Overview
The addition of hydrogen bromide to alkenes in the presence of hydroperoxides or peroxides proceeds via an anti-Markovnikov pathway and yields alkyl bromides.
02:50Catalysis
The presence of a catalyst affects the rate of a chemical reaction. A catalyst is a substance that can increase the reaction rate without being consumed during the process. A basic comprehension of a catalysts’ role during chemical reactions can be understood from the concept of reaction mechanisms and energy diagrams.