一个具有高度金字塔化的三坐标铁中心的铁硫星团与二的微不足道的亲和力
Alexandra C Brown1, Daniel L M Suess1
1Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States.
Journal of the American Chemical Society
|September 1, 2023
概括
研究人员开发了庞大的N-异环碳联体,以防止铁硫聚合,使得减少的[Fe4S4]0聚合物的研究成为可能. 由此产生的聚合物结合了CO,但由于Fe-N2结合不良,对N2的亲和力较弱.
科学领域:
- 有机金属化学
- 生物有机化学
- 协调化学
背景情况:
- 合成的铁硫是酶酶的关键模型.
- 产生N2结合的开放协调点往往导致不必要的集群寡合化.
- 在Mo-Fe-S集群中成功启动了N2复合体的形成.
研究的目的:
- 扩展使用固体保护性联体的策略到仅含Fe的Fe-S集群.
- 在减少Fe-S集群时抑制集群寡合化.
- 描述减少的[Fe4S4]0产品并研究其N2结合能力.
主要方法:
- 由N-异环碳酸 (IMes和SIAr) 支持的铁硫的合成和单电子还原.
- 使用固态要求的SIAr配体来防止集群寡合化.
- 使用光谱和结构方法对缩小集群进行表征.
- 研究生成的Fe-S集群的气体结合特性 (N2和CO).
主要成果:
- 在降解过程中,固态保护性SIAR配体成功阻止了Fe-S集群的寡合化.
- 缩小的[Fe4S4]0集群 (SIAr) 3Fe4S4的特征揭示了具有金字塔形状的独特的三坐标Fe位点.
- (SIAr) 3Fe4S4集群结合CO,但显示最小的N2协调,归因于弱的Fe-N2结合而不是固态阻碍.
结论:
- 在控制Fe-S集群的反应性方面,体体积大的N-异环碳素是有效的.
- 与Mo-Fe-S类似物相比,减少的[Fe4S4]0集群表现出不同的协调行为.
- 弱Fe-N2结合,而不是固体限制,解释了这些Fe-only集群中对N2的低亲和力.
相关概念视频
03:02Colors and Magnetism
11.8K
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...
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...
11.8K
02:30Chirality at Nitrogen, Phosphorus, and Sulfur
5.8K
Chirality is most prevalent in carbon-based tetrahedral compounds, but this important facet of molecular symmetry extends to sp3-hybridized nitrogen, phosphorus and sulfur centers, including trivalent molecules with lone pairs. Here, the lone pair behaves as a functional group in addition to the other three substituents to form an analogous tetrahedral center that can be chiral.
A consequence of chirality is the need for enantiomeric resolution. While this is theoretically possible for all...
A consequence of chirality is the need for enantiomeric resolution. While this is theoretically possible for all...
5.8K
02:42Valence Bond Theory
8.7K
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...
8.7K
02:34Structural Isomerism
19.3K
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...
19.3K
02:51Metal-Ligand Bonds
20.9K
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...
20.9K
02:57Coordination Number and Geometry
16.0K
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.
16.0K