一个八面体的结构,光谱和计算研究,非血[Fe-NO](6-8) 系列:[Fe(NO) ((环-ac) ]2+/+/0
Ricardo García Serres1, Craig A Grapperhaus, Eberhard Bothe
1Max-Planck-Institut für Bioanorganische Chemie, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany.
Journal of the American Chemical Society
|April 22, 2004
概括
本研究合成和表征了三种低旋转的非血红素铁酸复合物,特别是[FeNO]6,[FeNO]7和[FeNO]8系列. 这项研究澄清了这些难以捉摸的物种的电子结构和结合,提供了对其属性的全面了解.
科学领域:
- 无机化学 无机化学
- 生物有机化学 生物有机化学
- 计算化学计算化学
背景情况:
- 非血红铁酸盐复合物在生物系统中至关重要,但合成和表征具有挑战性.
- 了解这些复合物的电子结构是阐明它们的反应性和功能的关键.
- [FeNO]n系列代表不同氧化状态和铁-酸盐相互作用的结合方式.
研究的目的:
- 合成和描述一系列低旋转的非血红素铁酸复合物,特别是[FeNO]6,[FeNO]7和[FeNO]8.
- 阐明这些复合体的电子结构,结合和光谱特性.
- 用先进的计算方法提供对实验数据的详细解释.
主要方法:
- 使用1,4,8,11-tetraazacyclotetradecane-1-acetic acid (cyclam-ac) 合成铁酸复合物.
- 光谱表征包括EPR,UV-vis,Mössbauer和IR光谱学.
- 用于结构确定的X射线晶体学.
- 密度函数理论 (DFT) 计算用于电子结构和参数预测.
主要成果:
- 成功合成和描述了三种铁酸复合物:[FeNO]6 (1),[FeNO]7 (2) 和[FeNO]8 (3).
- 实验和计算数据证实了每个物种的电子结构和结合.
- 复合体1具有具有协调的酸 (NO+) 的铁离子,复合体2具有具有激素酸连接体 (NO*) 的铁离子,复合体3具有协调的酸离子 (NO-) 的铁离子.
结论:
- 这项研究明确地确定了难以捉摸的[FeNO]8物种 (3),这是一个低旋转的铁复合体,具有协调的NO-合体.
- 已经建立了[FeNO]6-8系列的详细结合图,解释了所有光谱和几何观测.
- 这些发现提供了对低旋转非血红素铁酸盐复合物及其电子配置的全面了解.
相关概念视频
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:
02:52Resonance
The Lewis structure of a nitrite anion (NO2−) may actually be drawn in two different ways, distinguished by the locations of the N-O and N=O bonds.
02:55Exceptions to the Octet Rule
Many covalent molecules have central atoms that do not have eight electrons in their Lewis structures. These molecules fall into three categories:
02:57Coordination Number and Geometry
For transition metal complexes, the coordination number determines the geometry around the central metal ion. Table 1 compares coordination numbers to molecular geometry. The most common structures of the complexes in coordination compounds are octahedral, tetrahedral, and square planar.
03:02Colors and Magnetism
Color in Coordination Complexes
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human eye.
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human eye.
02:16Resonance and Hybrid Structures
According to the theory of resonance, if two or more Lewis structures with the same arrangement of atoms can be written for a molecule, ion, or radical, the actual distribution of electrons is an average of that shown by the various Lewis structures.
Resonance Structures and Resonance Hybrids
The Lewis structure of a nitrite anion (NO2−) may actually be drawn in two different ways, distinguished by the locations of the N–O and N=O bonds.
Resonance Structures and Resonance Hybrids
The Lewis structure of a nitrite anion (NO2−) may actually be drawn in two different ways, distinguished by the locations of the N–O and N=O bonds.