铜 (I) 和铜 (II) 复合物具有交联的伊米达-联体:结构和二氧化物反应性
Kaliappan Kamaraj1, Eunsuk Kim, Benedikt Galliker
1Department of Chemistry, The Johns Hopkins University, Baltimore, Maryland 21218, USA.
Journal of the American Chemical Society
|June 6, 2003
概括
研究人员合成了新型的铜复合物与交叉链接的伊米达-联体,以模仿细胞染色体c氧化酶的活性部位. 这些复合体揭示了催化二氧化碳还原机制,涉及电子和质子转移.
科学领域:
- 生物有机化学 生物有机化学
- 生物物理化学 生物物理化学
- 协调化学 协调化学
背景情况:
- 细胞染色体c氧化酶对于细胞呼吸至关重要,催化氧气减少.
- 它的活性部位具有异构核血a3-CuB核.
- 一个独特的交叉链接的氨酸-氨酸部分被认为对催化作用至关重要.
研究的目的:
- 合成和特征铜复合物,模拟交叉链接的histidine-tyrosine部分.
- 研究这些复合物的与二氧化碳的反应性.
- 为了深入了解催化二氧化碳还原的机制.
主要方法:
- 合成四酸和三酸二甲基胺配体与伊米达/安尼索尔交叉链接.
- 使用X射线晶体学对铜 (I/II) 复合物的表征.
- 对二氧化碳结合和与铜复合物的反应进行光谱和动力学研究.
主要成果:
- 铜复合物与伊米达-/安尼索尔交叉链接成功合成和特征.
- 复合物与二氧化物发生反应,形成过渡的过氧物种和稳定的二度铜 (II) - 酸复合物.
- 为了形成这些二维复合体,获得了动力学和热力学数据.
结论:
- 合成的铜复合物作为细胞染色体c氧化酶中交叉链接的histidine-tyrosine部分的功能模型.
- 这项研究提供了宝贵的洞察力,了解了这种部分在氧气还原过程中电子和质子转移中的作用.
- 这些发现有助于理解参与呼吸的金属酶的复杂机制.
相关概念视频
02:54Coordination Compounds and Nomenclature
In most main group element compounds, the valence electrons of the isolated atoms combine to form chemical bonds that satisfy the octet rule. For instance, the four valence electrons of carbon overlap with electrons from four hydrogen atoms to form CH4. The one valence electron leaves sodium and adds to the seven valence electrons of chlorine to form the ionic formula unit NaCl (Figure 1a). Transition metals do not normally bond in this fashion. They primarily form coordinate covalent bonds, a...
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...
02:34Structural 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...
01:23Properties of Organometallic Compounds
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.
01:19Complexation Equilibria: The Chelate Effect
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...
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...