隔离的七坐标Ru(IV) 模态复合物与[HOHOH](-) 桥接联体作为催化水氧化过程中的中间体
Lele Duan1, Andreas Fischer, Yunhua Xu
1Department of Chemistry, School of Chemical Science and Engineering, Royal Institute of Technology (KTH), 100 44 Stockholm, Sweden.
Journal of the American Chemical Society
|July 16, 2009
概括
研究人员开发了一种新型的 (II) 复合物,用于高效的水氧化催化,灵感来自Photosystem II. 一个令人惊的七坐标的鲁丁 ((IV) 模态中间体与一个独特的桥接配体被发现,推进了人工光合作用研究.
科学领域:
- 无机化学 无机化学 有机化学
- 催化剂是一种催化剂.
- 人工光合作用的人工光合作用
背景情况:
- 光系统II (PSII) 中的氧进化复合体 (OEC) 是水氧化的自然催化剂.
- 有效的人工光合作用需要强大的催化剂,使水分裂产生燃料.
- 复合物是水氧化催化剂的有希望的候选者.
研究的目的:
- 为了合成和表征一种单核 (Ruthenium) 复合物,用于氧化水.
- 研究催化机制并确定反应中间体.
- 探索水氧化催化剂中的新型结构图案.
主要方法:
- 一个单核Ru (II) 复合物的合成和结构特征.
- 用 ((IV) 酸作为化学氧化剂进行催化水氧化.
- 使用X射线结晶学和HR-MS.隔离和表征Ru(III) 和Ru(IV) 中间体.
主要成果:
- 合成的Ru (II) 复合物显示出对水的氧化具有高效的催化活性.
- (III) 和 (IV) 种类被成功分离为中间物质.
- 发现了一种具有[HOHOH](-) 桥接联体的新型七坐标Ru(IV) 二元复合体,具有短的O-O距离和键网络.
结论:
- 发现罕见的七坐标的Ru (IV) 二次体为我们提供了关于水氧化机制的见解.
- 这些发现为设计更高效的氧化水催化剂提供了新的途径.
- 这项研究有助于推进太阳能转化人工光合作用.
相关概念视频
02:44Oxidation 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.
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.
02:15Preparation of Alcohols via Addition Reactions
Overview
The acid-catalyzed addition of water to the double bond of alkenes is a large-scale industrial method used to synthesize low-molecular-weight alcohols. An acidic atmosphere is required to allow the hydrogen in the water molecule to act as an electrophile and attack the double bond in an alkene. The addition of a proton to the double bond creates a carbocation intermediate. The proton preferentially bonds to the less substituted end of the double bond to create a more stable carbocation...
The acid-catalyzed addition of water to the double bond of alkenes is a large-scale industrial method used to synthesize low-molecular-weight alcohols. An acidic atmosphere is required to allow the hydrogen in the water molecule to act as an electrophile and attack the double bond in an alkene. The addition of a proton to the double bond creates a carbocation intermediate. The proton preferentially bonds to the less substituted end of the double bond to create a more stable carbocation...
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.
02:37Oxidation of Alcohols
In this lesson, the oxidation of alcohols is discussed in depth. The various reagents used for oxidation of primary and secondary alcohols are detailed, and their mechanism of action is provided.
The process of oxidation in a chemical reaction is observed in any of the three forms:
The process of oxidation in a chemical reaction is observed in any of the three forms:
03:08Hydroboration-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.