マグネシウムベースのメタロリガンドによる平面的ニッケラスピロペンタン複合体:合成,構造,シネージスティック二酸化水素活性化
Yanping Cai1, Shengjie Jiang1, Thayalan Rajeshkumar2
1Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou215123, P. R. China.
Journal of the American Chemical Society
|August 30, 2022
まとめ
この研究は,マグネシウム結合体を持つ新しい平面ニッケル-ビス-サイクロパンの複合体を明らかにし,伝統的な結合理論に挑戦しています. この複合体は,独特のMg/Ni協力機構を通じて水素を活性化し,水素化反応を触媒化する.
科学分野:
- 有機金属化学
- 協調化学
- キャタリシス
背景:
- デワー・チャット・ダンカンソンモデルは,移行金属・オレフィン結合をπ-コンプレックスと金属サイクロプロパン間の連続体として記述している.
- 教科書の規則は,遅い移行金属-エチレン複合体は,金属サイクロプロパンよりもπ複合体の形成を好むと予測する.
研究 の 目的:
- 低スピンの遅い移行金属ビスエチレン複合体を合成し,特徴づけること.
- 合成したヘトロトリメタリック複合体の結合性質と反応性を調べる.
- 水素の活性化と触媒活動のメカニズムを探る
主な方法:
- マグネシウムベースのメタロリガンドとNi ((cod) 2) を使ってヘトロトリメタリック複合体 (LMg) 2Ni ((C2H4) 2) の合成.
- 構造的特徴は,X線 difraktionとスペクトロスコピク方法を使用しています.
- 結合と反応メカニズムを解明するために密度関数理論 (DFT) を採用した計算研究.
- 様々な不飽和基質による水素化触媒実験
主要な成果:
- ニッケラスピロペンタンとして特定された,前例のない平面金属ビスサイクロパン構造の形成.
- 線形Mg-Ni-Mg結合とニッケル中心の平面調整幾何学の観測.
- H2への曝露時に4ヒドリドブリッジ複合体 (LMg) 2Ni ((μ-H)) 4に変換する.
- 金属の酸化なしに,新しいMg/Ni協力的なH2活性化メカニズムを解明する.
- 温和な条件下で様々な不飽和基質の水素化における触媒活性を示す.
結論:
- 合成された複合体は,確立された結合パラダイムに挑戦する平面金属サイクロプロパンの希少な例です.
- H2活性化のためのMg/Ni協力メカニズムは,触媒における金属-リガンドの協力に関する新しい視点を提供します.
- ヘトロトリメタリック複合体は,水素化反応の触媒として有意な可能性を示している.
関連する概念動画
02:51Metal-Ligand Bonds
21.4K
The hemoglobin in the blood, the chlorophyll in green plants, vitamin B-12, and the catalyst used in the manufacture of polyethylene all contain coordination compounds. Ions of the metals, especially the transition metals, are likely to form complexes.
In these complexes, transition metals form coordinate covalent bonds, a kind of Lewis acid-base interaction in which both of the electrons in the bond are contributed by a donor (Lewis base) to an electron acceptor (Lewis acid). The Lewis acid in...
In these complexes, transition metals form coordinate covalent bonds, a kind of Lewis acid-base interaction in which both of the electrons in the bond are contributed by a donor (Lewis base) to an electron acceptor (Lewis acid). The Lewis acid in...
21.4K
02:42Valence Bond Theory
9.1K
Coordination compounds and complexes exhibit different colors, geometries, and magnetic behavior, depending on the metal atom/ion and ligands from which they are composed. In an attempt to explain the bonding and structure of coordination complexes, Linus Pauling proposed the valence bond theory, or VBT, using the concepts of hybridization and the overlapping of the atomic orbitals. According to VBT, the central metal atom or ion (Lewis acid) hybridizes to provide empty orbitals of suitable...
9.1K
02:17Reduction of Alkenes: Asymmetric Catalytic Hydrogenation
3.4K
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...
3.4K
![[4+2] Cycloaddition of Conjugated Dienes: Diels–Alder Reaction](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2Ffiles%2Fmedia%2Fscience-education%2Fscience-education-thumbs%2F12417.jpg&w=3840&q=75)
01:16[4+2] Cycloaddition of Conjugated Dienes: Diels–Alder Reaction
10.4K
The Diels–Alder reaction is an example of a thermal pericyclic reaction between a conjugated diene and an alkene or alkyne, commonly referred to as a dienophile. The reaction involves a concerted movement of six π electrons, four from the diene and two from the dienophile, forming an unsaturated six-membered ring. As a result, these reactions are classified as [4+2] cycloadditions.
10.4K
02:34Structural Isomerism
19.6K
Isomerism in Complexes
Isomers are different chemical species that have the same chemical formula. Structural isomerism of coordination compounds can be divided into two subcategories, the linkage isomers and coordination-sphere isomers.
Linkage isomers occur when the coordination compound contains a ligand that can bind to the transition metal center through two different atoms. For example, the CN− ligand can bind through the carbon atom or through the nitrogen atom. Similarly, SCN− can...
Isomers are different chemical species that have the same chemical formula. Structural isomerism of coordination compounds can be divided into two subcategories, the linkage isomers and coordination-sphere isomers.
Linkage isomers occur when the coordination compound contains a ligand that can bind to the transition metal center through two different atoms. For example, the CN− ligand can bind through the carbon atom or through the nitrogen atom. Similarly, SCN− can...
19.6K
01:19Complexation Equilibria: The Chelate Effect
627
In complexation reactions, metal atoms or cations interact with ligands to form donor-acceptor adducts called metal complexes. Ligands that bind through one donor site are monodentate, ligands with two donor sites are bidentate, and those with more than two donor sites are polydentate ligands. For example, ethylene diamine is a bidentate ligand that binds through two nitrogen donor atoms, forming a five-membered ring. EDTA is a polydentate ligand that binds through four oxygen and two nitrogen...
627