通过激素连接体桥接的混合价值金属:基于结构-氧化状态相关性的事实或虚构
Biprajit Sarkar1, Srikanta Patra, Jan Fiedler
1Institut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring 55, D-70550 Stuttgart, Germany.
Journal of the American Chemical Society
|February 23, 2008
概括
富含电子的鲁复合体与双酸配体表现出显著的电荷转移. 双核化合物表现出混合价值状态和不寻常的氧化还原行为,具有挑战性的结构氧化状态相关性.
科学领域:
- 协调化学 协调化学
- 无机化学 无机化学 有机化学
- 材料科学 材料科学 材料科学
背景情况:
- (II) 复合物与缺电子连接体是电荷转移研究中的关键.
- 像阿扎比斯皮里丁 (abpy) 和阿扎比斯皮里米丁 (abcp) 这样的双酸配体促进金属到配体的电子转移.
- 了解双核复合体中的混合价值状态对于电子属性调节至关重要.
研究的目的:
- 为了合成和表征富含电子的Ru(acac) 2复合体与abpy和abcp连接体.
- 通过计算和实验方法研究电子结构和电荷转移特性.
- 探索双核混合系统的氧化还原行为和电子特性.
主要方法:
- 密度函数理论 (DFT) 计算用于结构和电子分析.
- 自然键轨道 (NBO) 分析以确认连接体电荷.
- 时间依赖的DFT (TD-DFT) 用于预测电子转换.
- 电化学和光谱电化学技术 (EPR,UV-vs-NIR) 用于氧化还原研究.
主要成果:
- 观察到从Ru(acac) 2到abpy和abcp带的显著电荷转移.
- 双核复合体表现出单离子桥接配体和值平均的Ru (III) Ru (II) 混合值状态.
- 电化学研究揭示了二核化合物异常的氧化还原通路,与单核类似物不同.
- 光谱电化学在还原和氧化时表明了不同的电子配置,EPR证实了氧化状态中的金属中心旋转.
结论:
- 这项研究证实了Ru(acac) 2复合体与双化物联体中的金属对联体电荷转移很大.
- 双核复合体表现出复杂的混合价值和氧化还原性质,突出显示了非无害连接体的作用.
- 这些发现提供了对结构-氧化状态相关性和混合价值协调化合物的行为的见解.
相关概念视频
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...
02:45Valence Bond Theory
Overview of Valence Bond Theory
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...
01:09Complexation Equilibria: Factors Influencing Stability of Complexes
In complexation reactions, metal cations are the electron pair acceptors, and the ligands are the electron pair donors. The stability of the metal complexes depends primarily on the complexing ability of the central metal ion and the nature of the ligands. Generally, the complexing ability of the metal ion depends on the size and charge of the ion. As the metal ion size increases, the stability of the metal complexes decreases, provided that the valency of the metal ion and the ligands remain...
02:58Properties 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.
02:48Ionic Bonding and Electron Transfer
Ions are atoms or molecules bearing an electrical charge. A cation (a positive ion) forms when a neutral atom loses one or more electrons from its valence shell, and an anion (a negative ion) forms when a neutral atom gains one or more electrons in its valence shell. Compounds composed of ions are called ionic compounds (or salts), and their constituent ions are held together by ionic bonds: electrostatic forces of attraction between oppositely charged cations and anions.