用单位-异极聚状态复合物氧化水的催化机制
Masato Murakami1, Dachao Hong, Tomoyoshi Suenobu
1Department of Material and Life Science, Graduate School of Engineering, Osaka University, Suita, Osaka 565-0871, Japan.
Journal of the American Chemical Society
|June 28, 2011
概括
复合物与异质聚变状态催化剂有效地从水中产生氧气. 同位素研究证实了氧气来源,Ru(V) -oxo物种是催化水氧化机制的关键.
科学领域:
- 无机化学 无机化学
- 催化剂是一种催化剂.
- 电化学 电化学 电化学
背景情况:
- 水的氧化对于能量转化和氧气生产至关重要.
- 开发高效和强大的催化剂来氧化水仍然是一个重大挑战.
- 单核复合体为催化应用提供可调节的电子特性.
研究的目的:
- 为了合成和表征具有Keggin型异构语言状态的全无机单核复合体.
- 为了研究这些复合物的催化活性在水氧化使用 (IV) 氧化剂.
- 阐明催化氧化水的机制,并确定活性中间体.
主要方法:
- - 异质复合体复合物的合成和表征.
- 电化学研究包括循环电压测量和普尔贝克斯图.
- 同位素标记实验,以追踪氧原子的起源.
- 现场光谱技术 (UV可见,EPR,共振拉曼) 检测活动物种.
主要成果:
- 复合物[Ru(III) (((H(2) O) SiW(11) O(39) ](5-) (1) 和[Ru(III) (((H(2) O) GeW(11) O(39) ](5-) (2) 已经成功合成.
- 这两种复合物都用酸 (CAN) 催化了水的氧化,复合物2显示出更高的反应性.
- 同位素标记证实,进化的氧源于水.
- 一种Ru(V) -oxo物种被确定为活性中间体,参与了确定速率的步骤.
结论:
- 全无机单核复合物含有异构态,是水氧化的有效催化剂.
- 催化循环涉及到Ru(V) -oxo中间体的形成和参与.
- 该研究提供了对催化水氧化机制的见解,为改进催化剂设计铺平了道路.
相关概念视频
Heterogeneous Catalysis
Heterogeneous catalysis involves a catalyst in a different phase from the reactants. It is a process where the catalyst and the reactants are in distinct phases, typically solid and gas or liquid.Most heterogeneous catalysts are metals, metal oxides, or acids. The list includes transition metals like iron (Fe), cobalt (Co), nickel (Ni), palladium (Pd), platinum (Pt), chromium (Cr), manganese (Mn), tungsten (W), silver (Ag), and copper (Cu). These metals possess partially vacant d orbitals that...
Catalysis
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.
Catalysis
Catalysis influences the rate of chemical reactions by providing an alternative reaction pathway with lower activation energy. A catalyst speeds up a reaction, but it is not consumed during the process. The fundamental principle of catalysis is the ability of a catalyst to alter the reaction mechanism, often introducing a more efficient pathway than the uncatalyzed process.In a catalyzed reaction, the catalyst participates directly in the reaction mechanism. It interacts with reactants to form...
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.
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.
Regioselectivity and Stereochemistry of Acid-Catalyzed Hydration
The rate of acid-catalyzed hydration of alkenes depends on the alkene's structure, as the presence of alkyl substituents at the double bond can significantly influence the rate.


