在Mn(IV) -peroxo和Mn(V) -oxo基层之间形成可逆的O-O键裂解和形成
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
概括
研究人员合成了 (IV) 和 (V) 氧,证明了可逆的氧-氧键裂变和形成. 这一突破为涉及氧物种的催化反应提供了新的途径.
科学领域:
- 无机化学 无机化学 有机化学
- 有机金属化学 有机金属化学
- 催化剂是一种催化剂.
背景情况:
- 角质是多用途的配体,在催化中具有应用.
- 了解高价值氧物种的反应性对于开发新的催化转换至关重要.
研究的目的:
- 为了合成和表征 (IV) - 和 (V) - .
- 研究涉及这些中间体的O-O键裂和形成反应.
- 为了证明这些O-O债券转换的可逆性.
主要方法:
- (IV) - 和 (V) - 的合成.
- 使用各种光谱技术进行表征.
- 在现场监测反应中间体和转化.
主要成果:
- 成功合成和表征了Mn(IV) -peroxo和Mn(V) -oxo基层.
- 在Mn(IV) -peroxo 冠状体的质子化后,O-O 键裂变的证明,以形成Mn(V) -oxo 冠状体.
- 在添加基于Mn{\displaystyle V} -oxo corrole后观察可逆的O-O键形成,再生Mn{\displaystyle IV} -peroxo corrole.
结论:
- 报告了第一个可逆的O-O键裂解和形成反应的例子,使用在位生成的Mn(IV) -peroxo和Mn(V) -oxo.
- 这些发现为介导的氧激活和转化提供了新的机理洞察力.
- 这些反应的可逆性开辟了新型催化应用的可能性.
相关概念视频
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.