(III) 碳素复合物具有类似于环金属化 (III) 化合物的电子激发状态结构
Narayan Sinha1, Björn Pfund1, Christina Wegeberg1
1Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056 Basel, Switzerland.
Journal of the American Chemical Society
|May 27, 2022
概括
研究人员开发了一种新的 (III) 复合物,具有与复合物相似的光活性金属-电荷转移 (MLCT) 特性. 这一突破为光化学中的第一排过渡金属提供了新的可能性.
科学领域:
- 无机化学
- 摄影化学
- 材料科学
背景情况:
- 已知有机金属 (III) 复合物具有混合金属至连接体和连接体内电荷转移 (MLCT/ILCT) 特性,可用于光物理和光化学.
- 具有类似MLCT激发状态特性的 (III) 复合体在很大程度上尚未被探索,尽管它与 (III) 具有低旋转的d6电子配置.
研究的目的:
- 合成和描述表现出光活性MLCT兴奋状态的 (III) 复合物.
- 研究 (III) 复合物的光物理和光化学特性.
- 探索与组金属相似的光物理特征的第一排过渡金属复合物的新连接物设计原理.
主要方法:
- 合成一种强大的同质性 (III) 复合物,Co (LCNC) 2,PF6,使用一种刚性三角酸联体 (LCNC).
- 结构,电化学和紫外线对短暂吸收的研究.
- 用同电子铁 (II) 复合体进行比较分析,特别是Fe (L) (CNC) (sub2) (PF) (sub6).
主要成果:
- 合成的 (III) 复合物,Co (L) (CNC) (sub) 2 (sub) (PF) (sub) 6 (sub),表现出具有显著的MLCT特征的光活性激发状态.
- 在 (III) 复合体中,MLCT状态与相似的铁 (II) 复合体相比具有显著的长寿命,这是由于降低了向低层金属中心状态的失活.
- MLCT状态直接参与光诱导的电子转移反应.
结论:
- (III) 复合物可以设计为具有长寿命光活性MLCT状态,类似于复合物.
- 开发的配体 (LCNC) 便于创建具有理想光物理性质的强大的复合物.
- 这项研究为第一排过渡金属的配体设计提供了洞察力,使以前由白金组金属主导的光物理和光化学应用成为可能.
相关概念视频
02:42Valence Bond Theory
9.7K
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...
9.7K
03:02Colors and Magnetism
12.4K
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...
12.4K
02:34Structural Isomerism
19.8K
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...
19.8K
02:58Crystal Field Theory - Octahedral Complexes
28.0K
Crystal Field Theory
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
28.0K
03:45Formation of Complex Ions
24.0K
A type of Lewis acid-base chemistry involves the formation of a complex ion (or a coordination complex) comprising a central atom, typically a transition metal cation, surrounded by ions or molecules called ligands. These ligands can be neutral molecules like H2O or NH3, or ions such as CN− or OH−. Often, the ligands act as Lewis bases, donating a pair of electrons to the central atom. These types of Lewis acid-base reactions are examples of a broad subdiscipline called coordination...
24.0K
01:19Complexation Equilibria: The Chelate Effect
693
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...
693