氧化状态III,IV和V的化复合物:合成和电子结构
Henning Kropp1, Amanda E King, Marat M Khusniyarov
1Department of Chemistry and Pharmacy, Inorganic Chemistry, Friedrich-Alexander University of Erlangen-Nuremberg, Egerlandstrasse 1, Erlangen, Germany.
Journal of the American Chemical Society
|August 28, 2012
概括
研究人员使用三脚式tris ((carbene)) 连接物合成了新的化. 这项研究详细介绍了化在各种氧化状态的特征,包括Mn (IV),Mn (V) 和Mn (III),揭示了独特的电子基态.
科学领域:
- 无机化学 无机化学
- 有机金属化学 有机金属化学
- 材料科学 材料科学 材料科学
背景情况:
- 化是各种催化过程中至关重要的中间体.
- 了解化的电子结构和反应性是开发新催化剂的关键.
- 三脚合联体为金属复合体提供独特的协调环境.
研究的目的:
- 在三脚三 () 联体框架内合成和表征一系列化.
- 为了研究不同氧化状态的电子特性和基本状态.
- 探索连接体框架对化稳定性和反应性的影响.
主要方法:
- 酸前体的光解.
- 谱学表征 (例如,UV-Vis,EPR) 进行.
- 密度函数理论 (DFT) 的计算.
主要成果:
- 一个分子Mn(IV) 化物复合物的分离,[(TIMEN(xyl))Mn(N) ](+),具有双重基态.
- 合成一种五价Mn(V) 化物,[(TIMEN(xyl)) Mn(N) ](2+),表现出三重基态,与之前报道的四角形类似物不同.
- 一种三价Mn{\displaystyle M_{\displaystyle M_{\displaystyle M_{\displaystyle M_{\displaystyle M_{\displaystyle M_{\displaystyle M_{\displaystyle M_{\displaystyle M_{\displaystyle M_{\displaystyle M_{\displaystyle M_{\displaystyle M_{\displaystyle M_{\displaystyle M_{\displaystyle M_{\displaystyle M_{\displaystyle M_{\displaystyle M_{\}}}}三价Mn{\displaystyle M_{\displaystyle M_{\displaystyle M_{\displaystyle M_{\displaystyle M_{\displaystyle M_{\displaystyle M_{\displaystyle M_{\displaystyle M_{\displaystyle M_{\}}}}三价Mn{\displaystyle M_{\displaystyle M_{\displaystyle M_{\displaystyle M_{\displaystyle M_{\displaystyle M_{\}}三价Mn{\displaystyle M_{\displaystyle M_{\displaystyle M_{\displaystyle M_{\}}
结论:
- 三脚三碳联体框架稳定了各种化物种.
- 化的电子基态对氧化状态和协调几何敏感.
- 这项工作为化的基本化学提供了洞察力,这与催化和材料科学有关.
相关概念视频
Properties of Transition Metals
Transition metals are defined as those elements that have partially filled d orbitals. As shown in Figure 1, the d-block elements in groups 3–12 are transition elements. The f-block elements, also called inner transition metals (the lanthanides and actinides), also meet this criterion because the d orbital is partially occupied before the f orbitals.
Valence Bond Theory
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...
Coordination 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...
Coordination 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.
Colors 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.
Structural 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...


