孤立した複合体内のpi/pi相互作用を通じて,難解なオルトキノン/銅の酸化状態の組み合わせを安定させる
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
まとめ
この研究は,pi/pi相互作用によって安定した,還元されていないオルトキノンを持つ新しい銅 (((I)) 複合体を特定しています. これらの相互作用は,銅に影響を与えます.
科学分野:
- 協調化化学について
- 有機金属化学 有機金属化学
- 超分子化学 超分子化学
背景:
- オーソキノンは通常,複合化前に減少します.
- 金属複合体における還元されていないオルトキノンの安定化は困難です.
- 金属複合体の非共性相互作用を理解することは極めて重要です.
研究 の 目的:
- 完全に還元されていないオルトキノンの銅 (((I) 複合体を合成し,特徴づけること.
- この複合体の安定化における pi/pi 相互作用の役割を調査する.
- 複合体の電気化学的性質と還元産物を調査する.
主な方法:
- シングルクリスタルX線結晶学
- 核磁共振 (NMR) スペクトロスコーピーは,核磁共振 (NMR) のスペクトロスコーピーを用います.
- 赤外線 (IR) スペクトロスコーピーは,赤外線 (IR) スペクトロスコーピーを用います.
- 紫外線可視 (UV-vis) スペクトルスコピー
- 密度関数理論 (DFT) の計算
- 電気化学の研究 電気化学の研究
- 電子パラマグネティック共振 (EPR) スペクトロスコピー
主要な成果:
- ヘテロディヌクレア銅 ((I) 複合体, [ ((PhenQ) Cu ((dppf) ] ((BF4) が合成され,特徴づけられ,完全に還元されていないオルトキノン (PhenQ) が特徴付けられました.
- 結晶学およびDFTの結果は,分子内フェニル/PhenQ pi/pi相互作用が複合体を安定させ,分子間PhenQ/PhenQ piの積み重ねも観察されたことを示しています.
- DFTの計算は,これらのπ相互作用がCu(Iで歪んだ座標幾何学を引き起こすことを明らかにし,Cu-OとCu-P結合の長さの変化と幅広い結合角度 (99~133度) によって証明されています.
- 低温での電気化学的還元により,EPRスペクトロスコーピーによって特徴づけられる,可逆性のある半キノーン-銅 (I) 種が生じた.
結論:
- この研究では,安定した還元されていないオルトキノンを持つ新しい銅 (I) 複合体を成功裏に合成し,特徴づけました.
- 分子内PI/PI相互作用は,難解なオルトキノンの配列を安定させ,調整幾何学に影響を与える上で重要な役割を果たします.
- 複合体は興味深い電気化学的振る舞いを示し,還元時にセミキノン・コッパー・I) 種を形成する.
関連する概念動画
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...

![[(DPEPhos)(bcp)Cu]PF6: A General and Broadly Applicable Copper-Based Photoredox Catalyst](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F59739.jpg&w=3840&q=50)
