富含氧气的集群电离子Al2O7+的结构及其对甲和水的反应性
Zhe-Chen Wang1, Thomas Weiske, Robert Kretschmer
1Institut für Chemie der Technischen Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany.
Journal of the American Chemical Society
|September 14, 2011
概括
氧化集群Al(2)O(7)(+) 通过原子转移与甲反应,通过连接物交换与水反应,释放氧气. 这项研究揭示了集群.
科学领域:
- 无机化学 无机化学 有机化学
- 物理化学 物理化学
- 计算化学计算化学
背景情况:
- 新型气相金属氧化物集群的生成和表征对于理解它们独特的化学特性至关重要.
- 研究富含氧气集群的反应性为氧化机制和潜在的催化应用提供了洞察力.
研究的目的:
- 为了阐明富含氧气的氧化集群的结构和反应性Al(2)O(7)(+).
- 探索Al(2)O(7)(+) 与甲 (CH(4) 和水 (H(2)O) 等小分子的反应途径.
- 为了确定氧气物种在Al(2) O(7)(+) 集群中的结构性作用.
主要方法:
- 气相发生的Al(2)O(7)(+) 集群.
- 使用里埃变换离子循环子共振 (FT-ICR) 质谱学的反应性研究.
- 在B3LYP/TZVP层面使用密度函数理论 (DFT) 计算的结构和机制研究.
- 碰撞诱导解离 (CID) 实验用于探测集群碎片化.
主要成果:
- 2O7+) 与CH4进行原子转移 (HAT),并与H2O交换配体,从而释放两个O2分子.
- 产物离子Al2O4H2O+保留了反应性,能够从CH4和H2O中抽取原子.
- 碰撞引起的解离和反应产物分析证实了两个O(2) 单元作为Al(2) O(7) ((+) 的组成结构组成部分的存在.
结论:
- 该研究成功地描述了Al(2)O(7)(+) 集群的结构和反应性.
- 实验和计算数据揭示了特定的反应机制,包括HAT和配体交换,突出显示了集群独特的化学行为.
- 这些发现为富含氧气的氧化集群中的结构动图和反应部位提供了基本的理解.
相关概念视频
Oxidative 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.
Aldehydes and Ketones with Water: Hydrate Formation
An oxygen-based nucleophile, like water, can undergo addition reactions with aldehydes and ketones. The reaction leads to the formation of hydrates, also referred to as 1,1-diols or geminal diols.
The formation of hydrates is a reversible reaction. Hydrate formation is influenced by steric and electronic factors accompanying the alkyl substituents on the carbonyl group: The rate of hydrate formation increases with a decrease in the number of alkyl groups attached to the carbonyl carbon. Hence,...
The formation of hydrates is a reversible reaction. Hydrate formation is influenced by steric and electronic factors accompanying the alkyl substituents on the carbonyl group: The rate of hydrate formation increases with a decrease in the number of alkyl groups attached to the carbonyl carbon. Hence,...
Hydroboration-Oxidation of Alkenes
In addition to the oxymercuration–demercuration method, which converts the alkenes to alcohols with Markovnikov orientation, a complementary hydroboration-oxidation method yields the anti-Markovnikov product. The hydroboration reaction, discovered in 1959 by H.C. Brown, involves the addition of a B–H bond of borane to an alkene giving an organoborane intermediate. The oxidation of this intermediate with basic hydrogen peroxide forms an alcohol.
Oxidation of Alkenes: Syn Dihydroxylation with Osmium Tetraoxide
Alkenes are converted to 1,2-diols or glycols through a process called dihydroxylation. It involves the addition of two hydroxyl groups across the double bond with two different stereochemical approaches, namely anti and syn. Dihydroxylation using osmium tetroxide progresses with syn stereochemistry.
Radical Substitution: Halogenation of Alkanes and Alkyl Substituents
In the presence of heat or light, alkanes react with molecular halogens to form alkyl halides by a substitution reaction called radical halogenation. This reaction has three steps: initiation, propagation, and termination, as seen in the radical chlorination of methane to produce methyl chloride.
In the initiation step of the reaction, the chlorine molecule undergoes homolytic cleavage in the presence of light or heat, forming two highly reactive chlorine radicals. Propagation occurs in two...
In the initiation step of the reaction, the chlorine molecule undergoes homolytic cleavage in the presence of light or heat, forming two highly reactive chlorine radicals. Propagation occurs in two...
Radical 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...


