Mn(IV) -ペロキソとMn(V) -オクソのコロール間の可逆的なO-O結合の割れと形成
Sun Hee Kim1, Hyejin Park, Mi Sook Seo
1Department of Bioinspired Science, Ewha Womans University, Seoul 120-750, Korea.
Journal of the American Chemical Society
|September 18, 2010
まとめ
研究者らは,マンガネス (IV) -ペロキソとマンガネス (V) -オキソカロールを合成し,可逆的な酸素-酸素結合の分裂と形成を証明した. この突破は,酸素種を含む触媒反応のための新しい経路を提供します.
科学分野:
- 無機化学 無機化学とは
- 有機金属化学 有機金属化学
- カタリシス カタリシス カタリシス
背景:
- マンガンのコロールは,触媒の応用のある多機能リガンドです.
- 高価率のマンガン-酸素種の反応性を理解することは,新しい触媒変換の開発に不可欠です.
研究 の 目的:
- マンガネス ((IV) -ペロキソとマンガネス ((V) -オキソのコーロールを合成し,特徴づけました.
- これらの中間物質を含むO−O結合割れと形成反応を調査する.
- これらのO-Oボンド変換の可逆性を実証するために.
主な方法:
- マンガネス ((IV) -ペロクソとマンガネス ((V) -オクソカロールの合成.
- さまざまなスペクトロスコーピテクニックを用いた特徴付け.
- 反応中介物質と変換のインサイトモニタリング.
主要な成果:
- Mn(IV) -ペロクソとMn(V) -オクソコアロールの合成と特徴付けに成功しました.
- Mn(IV) -ペロキソコロールをプロトン化してMn(V) -オクソコロールを形成する際にO-O結合の裂解の実証.
- Mn(V) -オクソコーロールに塩基を加えると,Mn(IV) -ペロクソコーロールを再生する逆転性O-O結合形成の観察.
結論:
- 局所生成のMn(IV) -peroxoとMn(V) -oxoコーロールを用いた可逆的なO-O結合割れと形成反応の最初の例を報告しました.
- これらの発見は,マンガン媒介による酸素活性化と変換に関する新しいメカニズム的洞察を提供します.
- これらの反応の可逆性により,新しい触媒の応用の可能性が生まれます.
関連する概念動画
01:21Radical Oxidation of Allylic and Benzylic Alcohols
Activated manganese(IV) oxide can selectively oxidize allylic and benzylic alcohols via a radical intermediate mechanism. Primary allylic alcohols are oxidized to aldehydes, while secondary allylic alcohols yield ketones. The redox reaction of potassium permanganate with an Mn(II) salt such as manganese sulfate (under either alkaline or acidic conditions), followed by thorough drying, yields the oxidizing agent: activated MnO2. While MnO2 is insoluble in the solvents used for the reaction, the...
02:21Oxidation of Alkenes: Syn Dihydroxylation with Potassium Permanganate
Alkenes can be dihydroxylated using potassium permanganate. The method encompasses the reaction of an alkene with a cold, dilute solution of potassium permanganate under basic conditions to form a cis-diol along with a brown precipitate of manganese dioxide.
02:01Alkynes to Carboxylic Acids: Oxidative Cleavage
Alkynes undergo oxidative cleavage in the presence of oxidizing reagents like potassium permanganate and ozone. The triple bond — one σ bond and two π bonds — is completely cleaved, and the alkyne is oxidized to carboxylic acids. When warm and basic aqueous potassium permanganate is used as an oxidizing agent, alkynes are first converted to carboxylate salts via an unstable α-diketone intermediate. Further, a mild acid treatment protonates the carboxylate anions generating free carboxylic acid...
01:46Oxidative Cleavage of Alkenes: Ozonolysis
In ozonolysis, ozone is used to cleave a carbon–carbon double bond to form aldehydes and ketones, or carboxylic acids, depending on the work-up.
Ozone is a symmetrical bent molecule stabilized by a resonance structure.
Ozone is a symmetrical bent molecule stabilized by a resonance structure.
02:04Oxidation of Alkenes: Anti Dihydroxylation with Peroxy Acids
Diols are compounds with two hydroxyl groups. In addition to syn dihydroxylation, diols can also be synthesized through the process of anti dihydroxylation. The process involves treating an alkene with a peroxycarboxylic acid to form an epoxide. Epoxides are highly strained three-membered rings with oxygen and two carbons occupying the corners of an equilateral triangle. This step is followed by ring-opening of the epoxide in the presence of an aqueous acid to give a trans diol.
00:54Radical Formation: Homolysis
A bond is formed between two atoms by sharing two electrons. When this bond is broken by supplying sufficient energy, either two electrons can be taken up by one atom forming ions by the cleavage called heterolysis, or the two electrons are shared by two atoms, with one each creating radicals by the cleavage called homolysis.