![[(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)
リバーシブル銅 (II) / (I) 電気化学的ポテンシャルスイッチングは,可視光によって誘発された協調リング回転によって誘発されます
Michihiro Nishikawa1, Kuniharu Nomoto, Shoko Kume
1Department of Chemistry, School of Science, The University of Tokyo, 7-3-1 Hongo, Tokyo 113-0033, Japan.
Journal of the American Chemical Society
|May 29, 2012
まとめ
この研究では,光エネルギーによる分子回転を介して光エネルギーを電子信号に変換する新しい銅複合体を導入しました. このシステムは,ビスタブル状態と電気化学的ポテンシャルシフトを活用することによって,繰り返し可能な信号抽出を実証します.
科学分野:
- 協調化化学について
- フォトケミストリーは,写真化学です.
- 分子電子 (モレキュラー・エレクトロニクス)
背景:
- 分子内リガンドの回転は,金属複合体の電子状態と結合することができます.
- 分子スイッチングのために光エネルギーを活用するには,効率的なエネルギー変換機構が必要です.
研究 の 目的:
- 光を燃料とする分子内回転による電子信号の抽出のための金属複合システムの開発.
- 銅複合体における電子伝送と分子運動の関係を調査する.
主な方法:
- 銅 (((I) コンプレックスとピリミジン誘導体とダイミネリガンドの合成.
- サイクルボルトメトリーを用いた電気化学分析で,温度が変動する.
- レドックス反応と回転反応の動力学と熱力学の研究.
主要な成果:
- 銅複合体は,銅の酸化状態によって制御される,リガンドの回転に関連した二元安定状態を示す.
- リンガンドの回転は銅の状態では凍結しているが,低温では銅の状態では活性化している.
- 光と熱は回転を誘導し,重要な電気化学的ポテンシャルシフト (0.14V) を引き起こします.
- 銅 (II) の中間体を通って,転移性銅 (I) 状態へのバイパス経路が特定されました.
結論:
- 開発された銅複合体は,光燃料による分子回転から電子信号を繰り返し抽出する最初のシステムです.
- この研究は,光エネルギー変換と電気化学的ポテンシャルシフトに基づいた新しい分子シグナルシステムを提供します.
関連する概念動画
01:26Photochemical Electrocyclic Reactions: Stereochemistry
The absorption of UV–visible light by conjugated systems causes the promotion of an electron from the ground state to the excited state. Consequently, photochemical electrocyclic reactions proceed via the excited-state HOMO rather than the ground-state HOMO. Since the ground- and excited-state HOMOs have different symmetries, the stereochemical outcome of electrocyclic reactions depends on the mode of activation; i.e., thermal or photochemical.
Selection Rules: Photochemical Activation
Selection Rules: Photochemical Activation
01:26Thermal and Photochemical Electrocyclic Reactions: Overview
Electrocyclic reactions are reversible reactions. They involve an intramolecular cyclization or ring-opening of a conjugated polyene. Shown below are two examples of electrocyclic reactions. In the first reaction, the formation of the cyclic product is favored. In contrast, in the second reaction, ring-opening is favored due to the high ring strain associated with cyclobutene formation.
01:17Thermal Electrocyclic Reactions: Stereochemistry
The stereochemistry of electrocyclic reactions is strongly influenced by the orbital symmetry of the polyene HOMO. Under thermal conditions, the reaction proceeds via the ground-state HOMO.
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
03:02Colors 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.
01:12Cycloaddition Reactions: MO Requirements for Photochemical Activation
Some cycloaddition reactions are activated by heat, while others are initiated by light. For example, a [2 + 2] cycloaddition between two ethylene molecules occurs only in the presence of light. It is photochemically allowed but thermally forbidden.
01:34Woodward–Hoffmann Selection Rules and Microscopic Reversibility
Electrocyclic reactions, cycloadditions, and sigmatropic rearrangements are concerted pericyclic reactions that proceed via a cyclic transition state. These reactions are stereospecific and regioselective. The stereochemistry of the products depends on the symmetry characteristics of the interacting orbitals and the reaction conditions. Accordingly, pericyclic reactions are classified as either symmetry-allowed or symmetry-forbidden. Woodward and Hoffmann presented the selection criteria for...