来自的共价连接双金属二的特定位置电子结构 K-边缘X射线吸收光谱学
Elizabeth S Ryland1, Xiaolin Liu2, Gaurav Kumar1
1Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
The Journal of chemical physics
|February 28, 2024
概括
K边缘X射线吸收近边缘结构 (XANES) 光谱揭示了双金属组件中金属结合和酶桥原子的独特电子签名. 这种技术为光驱催化提供了对电子结构和带扭曲的敏感见解.
科学领域:
- 材料科学 材料科学 材料科学
- 频谱学是一种光谱学.
- 催化剂是一种催化剂.
背景情况:
- 带有桥接连体的双金属组件对于光驱动的催化是至关重要的.
- 了解这些复杂分子的电子结构是优化它们的催化活性的关键.
- K边缘X射线吸收近边缘结构 (XANES) 光谱是一种用于探测电子环境的强大工具.
研究的目的:
- 为了研究使用N K边缘XANES的tetrapyrido[3,2-a:2',3'-c:3′′,2′′-h:2′′′,3′′′-j]phenazine (tpphz) 桥接双金属组件的电子结构.
- 为了证明N K-edge XANES的特定位置灵敏度,以区分组件内的不同环境.
- 为了更好地理解光驱催化,将光谱特征与金属协调和结构性质相关联.
主要方法:
- 实验性NK边缘X射线吸收近边缘结构 (XANES) 光谱检测在tpphz桥接双金属复合物及其组成部分上进行.
- 时间依赖密度函数理论 (TD-DFT) 的计算被用来解释实验光谱和分配光谱特征.
- 分析的重点是前端特征,以识别phenazine桥原子和金属结合原子的独特电子签名.
主要成果:
- N K-edge XANES具有较高的位点灵敏度,可以清楚地区分酸桥原子与金属结合原子.
- 金属协调导致金属结合前边峰的显著能量转移,随着金属的d电子数量 (3d < 4d < 5d) 的增加而增加.
- 由于电子接受轨道的稳定,phenazine桥前边峰出现在较低的能量,并且光谱对tpphz桥结构扭曲很敏感.
结论:
- N K-edge XANES 在tpphz.com等复杂的桥接连体系统中作为电子结构的局部探针.
- 该技术可以区分参与光吸收后电子转移过程的联结体中心轨道.
- 这项研究为利用N K-edge XANES分析先进材料中的电子结构进行催化提供了基础.
更多相关视频
06:31Preparation of SNS CobaltII Pincer Model Complexes of Liver Alcohol Dehydrogenase
Published on: March 19, 2020
7.1K
11:04Ion Mobility-Mass Spectrometry Techniques for Determining the Structure and Mechanisms of Metal Ion Recognition and Redox Activity of Metal Binding Oligopeptides
Published on: September 7, 2019
9.2K
相关概念视频
02:42Valence Bond Theory
8.5K
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...
8.5K
02:34Structural Isomerism
19.2K
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...
19.2K
03:02Colors and Magnetism
11.7K
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...
11.7K
02:51Metal-Ligand Bonds
20.8K
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...
20.8K
01:20Spin–Spin Coupling: Two-Bond Coupling (Geminal Coupling)
1.0K
Two NMR-active nuclei bonded to a central atom can be involved in geminal or two-bond coupling. Geminal coupling is commonly seen between diastereotopic protons in chiral molecules and unsymmetrical alkenes, among others.
The central atom need not be NMR-active because its electrons are affected by the electron polarization of the spin-active atoms. However, spin information is transmitted less effectively than in one-bond coupling, and 2J values are usually weaker than 1J values. The energy of...
The central atom need not be NMR-active because its electrons are affected by the electron polarization of the spin-active atoms. However, spin information is transmitted less effectively than in one-bond coupling, and 2J values are usually weaker than 1J values. The energy of...
1.0K
02:46Crystal Field Theory - Tetrahedral and Square Planar Complexes
42.5K
Tetrahedral Complexes
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...
42.5K