基/离子对的标准氧化还原潜力
Claude P Andrieux1, Jean Pinson
1Laboratoire d'Electrochimie Moléculaire, Université Paris 7-Denis Diderot, Unité Mixte Université Paris 7-CNRS 7591, 2 Place Jussieu, 75251 Paris Cedex 05, France. andrieux@paris7.jussieu.fr
Journal of the American Chemical Society
|December 4, 2003
概括
在乙尼中的阿里尔盐经历一电子的减少,形成基. 然后,这些基因被减少或经历原子转移,正如电压测量和模拟所显示的那样.
科学领域:
- 电化学 电化学 电化学
- 有机化学 有机化学
- 物理化学 物理化学
背景情况:
- 阿里尔迪亚四博酸盐是多功能合成中间体.
- 了解它们的电化学还原对于控制反应通路至关重要.
研究的目的:
- 为了阐明aryldiazonium tetrafluoroborates在乙二中的电化学还原机制.
- 为了确定基/离子对的标准氧化还原潜力.
主要方法:
- 循环电压测量被用来研究电化学行为.
- 使用电磁模拟来确定动力学和热力学参数.
主要成果:
- 观察到一个两波的减小模式,表明一个逐步的过程.
- 确定基/离子对的标准氧化还原潜力为0.05 V/SCE.
- 基中间体经历竞争性减少和H原子转移.
结论:
- 减少机制涉及一个初始的电子转移,其次是激素形成.
- 确定的氧化还原潜能为基的稳定性提供了洞察力.
- 这项研究阐明了基消耗的竞争途径.
相关概念视频
Standard Electrode Potentials
On comparing the reactivity of silver and lead, it is observed that the two ionic species, Ag+ (aq) and Pb2+ (aq), show a difference in their redox reactivity towards copper: the silver ion undergoes spontaneous reduction, while the lead ion does not. This relative redox activity can be easily quantified in electrochemical cells by a property called cell potential. This property is commonly known as cell voltage in electrochemistry, and it is a measure of the energy which accompanies the charge...
Acidity and Basicity of Alcohols and Phenols
Like water, alcohols are weak acids and bases. This is attributed to the polarization of the O–H bond making the hydrogen partially positive. Moreover, the electron pairs on the oxygen atom of alcohol make it both basic and nucleophilic. Protonation of an alcohol converts hydroxide, a poor leaving group, into water—a good one. The two acid–base equilibria corresponding to ethanol are depicted below.
Oxidation of Phenols to Quinones
In the presence of oxidizing agents, phenols are oxidized to quinones. Quinones can be easily reduced back to phenols using mild reducing agents. The electron-donating hydroxyl group enhances the reactivity of the aromatic ring, enabling oxidation of the ring even in the absence of an α hydrogen.
o-hydroxy phenols are oxidized to o-quinones and p-hydroxy phenols to p-quinones. Such redox reactions involve the transfer of two electrons and two protons. The reversible redox property is crucial in...
o-hydroxy phenols are oxidized to o-quinones and p-hydroxy phenols to p-quinones. Such redox reactions involve the transfer of two electrons and two protons. The reversible redox property is crucial in...
Electron Paramagnetic Resonance (EPR) Spectroscopy: Organic Radicals
Ideally, an unpaired electron shows a single peak in the EPR spectrum due to the transition between the two spin energy states. However, coupling interactions can occur between the spins of the unpaired electron and any neighboring spin-active nuclei. This hyperfine coupling results in hyperfine splitting, where the EPR signal is split into multiplets. The signals split into 2nI + 1 peaks, where n is the number of equivalent nuclei and I is the nuclear spin. These splitting patterns provide...
Ladder Diagrams: Redox Equilibria
Ladder diagrams are useful tools for understanding redox equilibrium reactions, especially the effects of concentration changes on the electrochemical potential of the reaction. The vertical axis in the redox ladder diagrams represents the electrochemical potential, E. The area of predominance is demarcated using the Nernst equation.
Consider the Fe3+/Fe2+ half-reaction, which has a standard-state potential of +0.771 V. At potentials more positive than +0.771 V, Fe3+ predominates, whereas Fe2+...
Consider the Fe3+/Fe2+ half-reaction, which has a standard-state potential of +0.771 V. At potentials more positive than +0.771 V, Fe3+ predominates, whereas Fe2+...
Redox Equilibria: Overview
A reduction-oxidation reaction is commonly called a redox reaction. In a redox reaction, electrons are transferred from one species to another rather than being shared between or among atoms. The reducing agent or reductant is the species that loses electrons and gets oxidized in the process. The species that gains electrons and gets reduced in the process is the oxidizing agent or oxidant. Redox reactions are represented as two separate equations called half-reactions, where one equation...


