効率的な光化学二水素生成は,バイメタリックセルフクエニングメカニズムによって開始されます
Matthew B Chambers1, Daniel A Kurtz1, Catherine L Pitman1
1Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599-3290, United States.
Journal of the American Chemical Society
|September 28, 2016
まとめ
研究者達は,水素燃料を生産する可視光を用いた 人工光合成の非常に効率的な経路を発見しました この新しいメカニズムは 双金属の自己消火を伴うので 水素生成の量子収量も ほぼ一致します
科学分野:
- 写真化学
- 人工光合成
- カタリシス
背景:
- 人工光合成は,持続可能な燃料生産のための自然のプロセスを模倣することを目的としています.
- 光の吸収と化学燃料の生成を 効率的に組み合わせることは 重要な課題です
研究 の 目的:
- [Cp*Ir(bpy) H]+から可視光による水素 (H2) 生成のメカニズムを解明する.
- 触媒システムにおける結合形成と光吸収を統合するための新しい経路を特定する.
主な方法:
- 可視光下での[Cp*Ir(bpy) H]+ (1) を使用したH2生成のメカニズム研究.
- 時間の解像度を持つ光発光スペクトロスコーピー
- デュテリウムの運動同位体効果の研究と標識実験
主要な成果:
- 光化学的H2生成のための新しい,非常に効率的な経路が明らかにされました.
- 興奮状態の滅は酸に依存せず,観測可能なデュテリウム運動同位体効果はありませんでした.
- 電子移転による拡散限定バイメタリック自己消火は,主要なプロセスとして特定されました.
- 触媒の濃度が高い場合,H2の放出による量子産量は1に近づいた.
結論:
- この研究は,典型的な酸依存メカニズムとは異なる,光化学的H2生成のユニークな経路を明らかにしています.
- バイメタリック自己消火は,光吸収と結合形成を統合するための非常に効率的な戦略です.
- これらの発見は,[Cp*Ir(bpy) H]+および関連する複合体によって触媒化された変換に関する貴重な洞察を提供します.
さらに関連する動画
関連する概念動画
Photochemical Electrocyclic Reactions: Stereochemistry
2.4K
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
2.4K
The Z-Scheme of Electron Transport in Photosynthesis
14.7K
The light reactions of photosynthesis assume a linear flow of electrons from water to NADP+. During this process, light energy drives the splitting of water molecules to produce oxygen. However, oxidation of water molecules is a thermodynamically unfavorable reaction and requires a strong oxidizing agent. This is accomplished by the first product of light reactions: oxidized P680 (or P680+), the most powerful oxidizing agent known in biology. The oxidized P680 that acquires an electron from the...
14.7K
Catalysis
31.7K
The presence of a catalyst affects the rate of a chemical reaction. A catalyst is a substance that can increase the reaction rate without being consumed during the process. A basic comprehension of a catalysts’ role during chemical reactions can be understood from the concept of reaction mechanisms and energy diagrams.
31.7K
Reduction of Alkenes: Asymmetric Catalytic Hydrogenation
4.0K
Catalytic hydrogenation of alkenes is a transition-metal catalyzed reduction of the double bond using molecular hydrogen to give alkanes. The mode of hydrogen addition follows syn stereochemistry.
The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...
The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...
4.0K
Thermal and Photochemical Electrocyclic Reactions: Overview
3.2K
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.
3.2K
Radical Substitution: Hydrogenolysis of Alkyl Halides with Tributyltin Hydride
2.3K
Radical substitution reactions can be used to remove functional groups from molecules. The hydrogenolysis of alkyl halides is one such reaction, where the weak Sn–H bond in tributyltin hydride reacts with alkyl halides to form alkanes. Here, the reagent Bu3SnH yields tributyltin halide as a byproduct.
The bonds formed in this reaction are stronger than the bonds broken, making it energetically favorable. The reaction follows a radical chain mechanism similar to radical halogenation reactions,...
The bonds formed in this reaction are stronger than the bonds broken, making it energetically favorable. The reaction follows a radical chain mechanism similar to radical halogenation reactions,...
2.3K

![[DPEPhosbcpCu]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)
