混合铁μ-碳素,μ-化物复合物:对酶的影响
Charles H Arnett1, Isabel Bogacz2, Ruchira Chatterjee2
1Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States.
Journal of the American Chemical Society
|September 25, 2020
概括
使用二铁μ- 碳酸复合物建模了酶FeMo辅因子中间体. 氧化化学揭示了金属-联体共价的变化,这对于促进固定多电子转换至关重要.
科学领域:
- 生物有机化学
- 有机金属化学
- 生物化学
背景情况:
- 酶FeMo-辅因子 (FeMoco) 在4e-和4H转移后结合N2.
- 这种混合价值中间体的结构和电子学知之甚少.
- 脉冲EPR研究表明存在两个Fe-{-μ-H) -Fe部分.
研究的目的:
- 了解酶的生物有机金属集群.
- 以光谱来表征具有EPR活性的Fe-C-H-Fe模型复合物.
- 调查价值移位对μ-化物配体的影响.
主要方法:
- 双铁μ-碳化合物的合成和氧化还原处理.
- 脉冲电子磁共振 (EPR) 光谱学
- 射线吸收光谱,Fe Mössbauer研究和DFT计算.
主要成果:
- 描述了两个类似于酶E3和E4状态的EPR活性Fe(μ-C)(μ-H) 复合体.
- 这两种物种在低温下表现出S=1/2状态.
- 氧化还原化学诱导了Fe-C共价的显著变化 (在2e-减少时为50%).
结论:
- 在FeMoco E4(4H) 状态中的合体可能是同FeIII中心的桥梁.
- 协同变化缓冲金属的过剩电荷,通过将其重新分配到桥梁碳.
- 这种机制促进了固定所必需的多电子转换.
相关概念视频
1° Amines to Diazonium or Aryldiazonium Salts: Diazotization with NaNO2 Mechanism
4.5K
Nitrous acid is a relatively weak and unstable acid prepared in situ by the reaction of sodium nitrite and cold, dilute hydrochloric acid. In an acidic solution, the nitrous acid undergoes protonation when it loses water to form a nitrosonium ion—an electrophile. Nitrous acid reacts with primary amines to give diazonium salts. The reaction is called diazotization of primary amines.
4.5K
Properties of Organometallic Compounds
1.5K
Organometallic compounds are compounds that contain a carbon–metal bond. Carbon belongs to an organyl group like alkyl, aryl, allyl, or benzyl groups. The metal can be from Group I or Group II of the periodic table, a transition metal, or a semimetal.
1.5K
Structural Isomerism
21.0K
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...
21.0K
1° Amines to Diazonium or Aryldiazonium Salts: Diazotization with NaNO2 Overview
3.7K
Nitrous acid and nitric acids are two types of acids containing nitrogen, among which nitrous acid is weaker than nitric acid. Nitrous acid with a pKa value of 3.37 ionizes in water to give a nitrite ion and the hydronium ion.
The nitrous acid is unstable. Hence, it is formed in situ from a solution of sodium nitrite and cold aqueous acids such as hydrochloric or sulfuric acid. In an acidic solution, the –OH group of nitrous acid undergoes protonation to give oxonium ion, followed by...
The nitrous acid is unstable. Hence, it is formed in situ from a solution of sodium nitrite and cold aqueous acids such as hydrochloric or sulfuric acid. In an acidic solution, the –OH group of nitrous acid undergoes protonation to give oxonium ion, followed by...
3.7K
Metal-Ligand Bonds
23.2K
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...
23.2K
Valence Bond Theory
10.5K
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...
10.5K


