氧化的臭氧化物,环氧化物和氧化素的C(70) 的
Dieter Heymann1, Sergei M Bachilo, R Bruce Weisman
1Department of Earth Science, Rice Quantum Institute, Rice University, Houston, Texas 77251, USA.
Journal of the American Chemical Society
|May 30, 2002
概括
研究人员用臭氧化C70) 来制造新的氧气添加物. 这些臭氧化物通过热解或光解转化为各种C(70) O异构物,包括环氧化物和氧化烯.
科学领域:
- 富勒化学化学 富勒化学
- 有机化学 有机化学
- 摄影化学的使用.
背景情况:
- 富勒,如C70),是碳的异构体,具有独特的电子和结构性质.
- 富勒与氧物种的反应对于理解它们的化学反应性和潜在应用至关重要.
- 之前的研究已经探讨了C{60}的臭氧化,为与C{70) 的反应提供了比较的基础.
研究的目的:
- 用氧物种合成和表征C(70) 的新型单添加物.
- 为了研究C(70) 臭氧化物的热和光化学转化.
- 为了比较C(70) 臭氧化物与C(60) 的反应性.
主要方法:
- 臭氧化C ((70) 溶液以形成臭氧化单添加物.
- 由此产生的C(70) 氧添加物的分离和表征.
- 热解和光解实验用于研究臭氧化物分解途径.
主要成果:
- 成功地准备和识别了六种新的含氧C70的单添加物.
- 形成了两个初始的臭氧单添加物,a,b-和c,c-C(70) O(3).
- 这些臭氧化物的热解和光解产生了C(70) O的各种异构体,包括环氧化物和氧化素.
- 在热解过程中,a,b-C(70) O(3) 异构体选择性地形成了环氧化物,在光解过程中形成了氧化素.
- 在c,c-C(70) O(3) 异构体中显示出不同的热和光化学产物,热衰变导致氧化烯和光解产生氧化烯和较小的环氧化物混合物.
- 发现所有已识别的C(70) O氧化烯异构体都经历了光异构化到环氧化物.
结论:
- 臭氧化C70提供了各种氧化烯衍生物的获取机会.
- 臭氧化物C(70) 的独特热和光化学路径突出显示了立体化学对反应性的影响.
- 观察到的C(70) 臭氧化物反应与C(60) 臭氧化物反应相似,这表明富勒烯臭氧化解的一般机制.
相关概念视频
Oxidation 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.
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.
Structure and Nomenclature of Epoxides
Cyclic ethers are heterocyclic compounds with an oxygen atom in the ring along with carbon atoms. They are named depending on the number of carbon atoms present in their ring system. Cyclic ethers with a three-membered ring system are called “oxirane”, four-membered ring systems as “oxetane”, five-membered ring systems as “oxolane”, and six-membered ring systems as “oxane”. The cyclic structure of these rings imposes angle strain, and this strain is more in the ring having a smaller number of...
Preparation of Epoxides
Overview
Epoxides result from alkene oxidation, which can be achieved by a) air, b) peroxy acids, c) hypochlorous acids, and d) halohydrin cyclization.
Epoxidation with Peroxy Acids
Epoxidation of alkenes via oxidation with peroxy acids involves the conversion of a carbon–carbon double bond to an epoxide using the oxidizing agent meta-chloroperoxybenzoic acid, commonly known as MCPBA. Since the O–O bond of peroxy acids is very weak, the addition of electrophilic oxygen of peroxy acids to...
Epoxides result from alkene oxidation, which can be achieved by a) air, b) peroxy acids, c) hypochlorous acids, and d) halohydrin cyclization.
Epoxidation with Peroxy Acids
Epoxidation of alkenes via oxidation with peroxy acids involves the conversion of a carbon–carbon double bond to an epoxide using the oxidizing agent meta-chloroperoxybenzoic acid, commonly known as MCPBA. Since the O–O bond of peroxy acids is very weak, the addition of electrophilic oxygen of peroxy acids to...
Acid-Catalyzed Ring-Opening of Epoxides
Epoxides that are three-membered ring systems are more reactive than other cyclic and acyclic ethers. The high reactivity of epoxides originates from the strain present in the ring. This ring strain acts as a driving force for epoxides to undergo ring-opening reactions either with halogen acids or weak nucleophiles in the presence of mild acid. The acid catalyst converts the epoxide oxygen, a poor leaving group, into an oxonium ion, a better leaving group, making the reaction feasible. The...
Base-Catalyzed Ring-Opening of Epoxides
Due to their highly strained structures, epoxides can readily undergo ring-opening reactions through nucleophilic substitution, either in the presence of an acid or a base. The nucleophilic substitution reactions in the presence of acid are called acid-catalyzed ring-opening reactions, and nucleophilic substitution reactions in the presence of a base are called base-catalyzed ring-opening reactions. Epoxides undergo base-catalyzed ring-opening reactions in the presence of a strong nucleophile...

![Solid-phase Synthesis of [4.4] Spirocyclic Oximes](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F58508.jpg&w=3840&q=50)
![Cercosporin-Photocatalyzed [4+1]- and [4+2]-Annulations of Azoalkenes Under Mild Conditions](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F60786.jpg&w=3840&q=50)