在一个孤立的复合体中,通过pi/pi相互作用稳定难以捉摸的正/铜的氧化状态组合
Sayak Roy1, Biprajit Sarkar, Denis Bubrin
1Institut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring 55, D-70550 Stuttgart, Germany.
Journal of the American Chemical Society
|October 29, 2008
概括
这项研究确定了一种新型的铜 (I) 复合物与未减少的正基,通过pi/pi相互作用稳定. 这些相互作用会影响铜.
科学领域:
- 协调化学 协调化学
- 有机金属化学 有机金属化学
- 超分子化学 超分子化学
背景情况:
- 在复杂化之前,正类通常被减少.
- 在金属复合体中稳定未减少的正基具有挑战性.
- 了解金属复合体中的非共价相互作用至关重要.
研究的目的:
- 合成和表征一个完全未减少的正基的铜 (I) 复合体.
- 研究pi/pi相互作用在稳定这种复杂物质中的作用.
- 探索该复合体的电化学特性和还原产品.
主要方法:
- 单晶X射线晶体学 单晶X射线晶体学
- 核磁共振 (NMR) 光谱学 核磁共振 (NMR) 光谱学
- 红外 (IR) 光谱法 红外 (IR) 光谱法
- 紫外线可见 (UV-vis) 光谱学
- 密度函数理论 (DFT) 的计算.
- 电化学研究 电化学研究
- 电子偏磁共振 (EPR) 光谱学
主要成果:
- 一个异质核铜 (I) 复合体, (PhenQ) Cu (dppf) (BF4) 被合成和特征化,具有完全未减少的正 (PhenQ).
- 结晶学和DFT结果表明,分子内/PhenQ pi/pi相互作用稳定了该复合体,也观察到分子间PhenQ/PhenQ pi堆叠.
- DFT的计算显示,这些pi相互作用导致Cu(I处的协调几何扭曲,由不同的Cu-O和Cu-P键长和广泛的键角 (99-133度) 证明.
- 在低温下进行电化学还原,产生了可逆的半诺-铜 (I) 物种,其特点是EPR光谱学.
结论:
- 该研究成功合成并描述了一种新型的铜 (I) 复合物与稳定未减少的正.
- 分子内pi/pi相互作用在稳定难以捉摸的正基排列和影响协调几何学方面发挥着重要作用.
- 该复合体表现出有趣的电化学行为,在减少时形成半子-铜 (I) 种.
相关概念视频
Oxidation of Phenols to Quinones
In the presence of oxidizing agents, phenols are oxidized to quinones. Quinones can be easily reduced back to phenols using mild reducing agents. The electron-donating hydroxyl group enhances the reactivity of the aromatic ring, enabling oxidation of the ring even in the absence of an α hydrogen.
o-hydroxy phenols are oxidized to o-quinones and p-hydroxy phenols to p-quinones. Such redox reactions involve the transfer of two electrons and two protons. The reversible redox property is crucial in...
o-hydroxy phenols are oxidized to o-quinones and p-hydroxy phenols to p-quinones. Such redox reactions involve the transfer of two electrons and two protons. The reversible redox property is crucial in...
Complexation 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...
Extraction: Advanced Methods
Metal ions can be separated from one another by complexation with organic ligands–the chelating agent– to form uncharged chelates. Here, the chelating agent must contain hydrophobic groups and behave as a weak acid, losing a proton to bind with the metal. Since most organic ligands used in this process are insoluble or undergo oxidation in the aqueous phase, the chelating agent is initially added to the organic phase and extracted into the aqueous phase. The metal-ligand complex is formed in...
Formation of Complex Ions
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...
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.
Complexation Equilibria: Overview
Complexation reactions take place when dative or coordinate covalent bonds form between metal ions and ligands. The compounds formed in these reactions are called coordination compounds. The number of bonds formed between the metal ion and the ligands is called its coordination number. Generally, most metal ions in an aqueous solution are solvated by water molecules and thus exist as aqua complexes.
The equilibrium constant of the complexation reaction is represented as the formation constant...
The equilibrium constant of the complexation reaction is represented as the formation constant...

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