内部分子,分子间和异质的非adiabatic离散电子转移到peresters
S Antonello1, F Formaggio, A Moretto
1Department of Physical Chemistry, University of Padova, via Loredan 2, 35131 Padova, Italy.
Journal of the American Chemical Society
|September 27, 2001
概括
使用电化学研究了电子转移到佩雷斯特的情况. 该研究发现,这些离散电子转移强烈非离散,其速度明显低于理论上预测的极限.
科学领域:
- 电化学 电化学 电化学
- 物理化学 物理化学
- 有机化学 有机化学
背景情况:
- 降解机制对于理解电子转移过程至关重要.
- 电化学方法为研究电子转移动力学提供了精确的控制.
研究的目的:
- 通过使用各种电化学技术,研究电子转移到佩雷斯特.
- 阐明离散电子转移反应的非adiabatic性质和动力学.
主要方法:
- 使用玻璃碳电极进行异质电化学还原.
- 同质的氧化还原催化与电生成的基离子.
- 在捐赠器-空间器-接受器 (D-Sp-A) 系统中进行分子内电子转移研究.
- 卷积分析和循环电压测量模拟.
主要成果:
- 不同质的数据与离散电子转移理论保持一致.
- 同质催化证实了拟议的减少机制.
- 通过D-Sp-A分子模拟来确定分子内速率常数.
- 实验速率被发现是大小小小的数量级低于透性极限,表明强烈的非透性.
结论:
- 离散电子转移到佩雷斯特是强烈的非adiabatic.
- 观察到的缓慢速度表明一种特定的机械路径影响了电子传输效率.
相关概念视频
02:23Autoxidation of Ethers to Peroxides and Hydroperoxides
Ethers represent a class of chemical compounds that become more dangerous with prolonged storage because they tend to form explosive peroxides when standing in the air. Autoxidation is the spontaneous oxidation of a compound in air. In the presence of oxygen, ethers slowly oxidize to form hydroperoxides and dialkyl peroxides.
01:26Thermal and Photochemical Electrocyclic Reactions: Overview
Electrocyclic reactions are reversible reactions. They involve an intramolecular cyclization or ring-opening of a conjugated polyene. Shown below are two examples of electrocyclic reactions. In the first reaction, the formation of the cyclic product is favored. In contrast, in the second reaction, ring-opening is favored due to the high ring strain associated with cyclobutene formation.
01:17Thermal Electrocyclic Reactions: Stereochemistry
The stereochemistry of electrocyclic reactions is strongly influenced by the orbital symmetry of the polyene HOMO. Under thermal conditions, the reaction proceeds via the ground-state HOMO.
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
01:26Photochemical Electrocyclic Reactions: Stereochemistry
The absorption of UV–visible light by conjugated systems causes the promotion of an electron from the ground state to the excited state. Consequently, photochemical electrocyclic reactions proceed via the excited-state HOMO rather than the ground-state HOMO. Since the ground- and excited-state HOMOs have different symmetries, the stereochemical outcome of electrocyclic reactions depends on the mode of activation; i.e., thermal or photochemical.
Selection Rules: Photochemical Activation
Selection Rules: Photochemical Activation
00:54Radical Formation: Homolysis
A bond is formed between two atoms by sharing two electrons. When this bond is broken by supplying sufficient energy, either two electrons can be taken up by one atom forming ions by the cleavage called heterolysis, or the two electrons are shared by two atoms, with one each creating radicals by the cleavage called homolysis.
01:17Pericyclic Reactions: Introduction
Pericyclic reactions are organic reactions that occur via a concerted mechanism without generating any intermediates. The reactions proceed through the movement of electrons in a closed loop to form a cyclic transition state, where rearrangement of the σ and π bonds yields specific products.
Pericyclic reactions can be classified into three categories: electrocyclic reactions, cycloaddition reactions, and sigmatropic rearrangements. Electrocyclic reactions and sigmatropic rearrangements are...
Pericyclic reactions can be classified into three categories: electrocyclic reactions, cycloaddition reactions, and sigmatropic rearrangements. Electrocyclic reactions and sigmatropic rearrangements are...