超快联体交换:检测了五坐标的Ru (II) 中间体和产物形成
Yao Liu1, David B Turner, Tanya N Singh
1Department of Chemistry, The Ohio State University, Columbus, Ohio 43210, USA.
Journal of the American Chemical Society
|December 17, 2008
概括
在水和酸中研究了复合物的超快联体交换动力学. 一个五坐标中间体在2比秒内形成,影响激发状态动态和产品形成.
科学领域:
- 摄影化学的使用.
- 协调化学 协调化学
- 物理化学 物理化学
背景情况:
- 聚烯基复合物在光化学和催化中至关重要.
- 了解连接体交换动态对于预测反应性至关重要.
- 复合物的兴奋状态属性依赖于溶剂.
研究的目的:
- 为了研究cis-[Ru(bpy) 2(CH3CN) 2+2中的联结体交换的超快动力学.
- 阐明激发状态和中间体的形成和衰变路径.
- 为了比较水和乙二对反应动态的溶剂效应.
主要方法:
- 时间分辨率光谱学使用310nm激发,脉冲宽度为300 fs.
- 在不同的溶剂环境中对短暂物种的动态分析.
- 监测激发状态进化和配体重组过程.
主要成果:
- 在2皮秒内形成一个三重金属到合体电荷转移 ((3) MLCT) 激发状态和五坐标中间体.
- 兴奋状态的振动冷却发生在5-6个皮秒内.
- 基态再生的寿命大约为50皮秒,具有溶剂特定的连接物重组/形成时间.
结论:
- 这项研究揭示了复合体中的快速,溶剂介导的联结体交换通路.
- 一种短暂的五坐标中间体在反应机制中起着关键作用.
- 溶剂极性显著影响着连接体替代和重组的动力学.
更多相关视频
09:45Accessing Valuable Ligand Supports for Transition Metals: A Modified, Intermediate Scale Preparation of 1,2,3,4,5-Pentamethylcyclopentadiene
Published on: March 20, 2017
10:52Line Shape Analysis of Dynamic NMR Spectra for Characterizing Coordination Sphere Rearrangements at a Chiral Rhenium Polyhydride Complex
Published on: July 27, 2022
相关概念视频
02:58Crystal Field Theory - Octahedral Complexes
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...
00:43Complexometric Titration: Ligands
Different monodentate and polydentate ligands are used as complexing agents in complexometric titration reactions. The formation of complexes by mono- and bidentate ligands involves two or more intermediate steps, limiting their use as complexing agents. In comparison, polydentate ligands can form complexes with metal ions in a single-step process, facilitating sharper end points. This means polydentate ligands, such as amino carboxylic acid derivatives, are most commonly employed in...
02:42Valence 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...
02:51Metal-Ligand Bonds
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...