鉄のN-O結合ホモリシスによって,鉄のO-O結合ホモリシスによって,鉄のO-O結合ホモリシスによって,鉄のO-O結合ホモリシスによって,鉄のO-O結合ホモリシスによって,鉄のO-O結合ホモリシスによって,鉄のO-O結合ホモリシスによっ
Jeremy M Smith1, Derick E Mayberry, Charles G Margarit
1Department of Chemistry and Biochemistry, New Mexico State University, Las Cruces New Mexico 88003, USA. jesmith@nmsu.edu
Journal of the American Chemical Society
|March 29, 2012
まとめ
研究者はTEMPOを鉄 (I) 複合体と反応させ,安定した鉄 (II) 窒酸化物複合体を形成した. この複合体は熱分解され,酸素原子移転反応のための活性鉄 (III) オクソ中間体となる.
科学分野:
- 有機金属化学 有機金属化学
- 無機化学 無機化学とは
- 反応メカニズム 反応メカニズム
背景:
- 安定した鉄複合体は,触媒作用に不可欠である.
- 異なる酸化状態における鉄の反応性を理解することが鍵となる.
- TEMPO (2,2,6,6-テトラメチルピペリジン-1-イール) オクシルは,様々な化学的変換で使用される安定基である.
研究 の 目的:
- 新しいアイアン ((I) -TEMPO adduct.を合成し,特徴づけるために.
- 鉄-TEMPO複合体の反応性と分解経路を調査する.
- 酸素原子移転反応における鉄-オクソ中間物質の可能性を調査する.
主な方法:
- 鉄 ((I) 前駆体PhB ((MesIm) ((3) Fe ((COE)) の合成について.
- 鉄 (((I) コンプレックスとTEMPOの反応.
- X線結晶学およびスペクトロスコピー (NMR, EPR, Mössbauer) を用いた構造的特徴づけ.
- N-O結合ホモリシスを誘導するための熱溶解研究.
- トリフェニルメチルラジカルによるトラッピング実験.
主要な成果:
- 二価鉄がニトロキシドアニオンに結合した κ(1) -TEMPO複合体 PhB(MesIm)(3) Fe(TEMPO) の形成.
- 複合体は,鉄 (II) ペロキソ種に対するアイソエレクトロニックである.
- 熱分解により,鉄 (III) オクソ中間物質が生成された.
- 鉄 (III) オキシオ中介物質は,酸素原子移転における活性を示した.
- オキソ介質は,鉄 (((II) アルコキソ複合体PhB (((MesIm) (((3) Fe (((OCPh ((3)) を形成するために閉じ込められました.
結論:
- 新しい鉄 (II) 酸化窒素複合体を成功裏に合成し,特徴づけました.
- 鉄 (II) 複合体のN-O結合同解により,反応性鉄 (III) オクソ種が生じる.
- この鉄 (III) オクソ介質は酸素原子の移転が可能で,その触媒的可能性を強調しています.
関連する概念動画
00:54Radical Formation: Homolysis
A bond is formed between two atoms by sharing two electrons. When this bond is broken by supplying sufficient energy, either two electrons can be taken up by one atom forming ions by the cleavage called heterolysis, or the two electrons are shared by two atoms, with one each creating radicals by the cleavage called homolysis.
02:51Metal-Ligand Bonds
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...
02:54Lewis Structures of Molecular Compounds and Polyatomic Ions
To draw Lewis structures for complicated molecules and molecular ions, it is helpful to follow a step-by-step procedure as outlined:
03:08Hydroboration-Oxidation of Alkenes
In addition to the oxymercuration–demercuration method, which converts the alkenes to alcohols with Markovnikov orientation, a complementary hydroboration-oxidation method yields the anti-Markovnikov product. The hydroboration reaction, discovered in 1959 by H.C. Brown, involves the addition of a B–H bond of borane to an alkene giving an organoborane intermediate. The oxidation of this intermediate with basic hydrogen peroxide forms an alcohol.
02:34Structural Isomerism
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 be...
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 be...
01:09Complexation Equilibria: Factors Influencing Stability of Complexes
In complexation reactions, metal cations are the electron pair acceptors, and the ligands are the electron pair donors. The stability of the metal complexes depends primarily on the complexing ability of the central metal ion and the nature of the ligands. Generally, the complexing ability of the metal ion depends on the size and charge of the ion. As the metal ion size increases, the stability of the metal complexes decreases, provided that the valency of the metal ion and the ligands remain...