通过定量结构和离子对平衡的分子间电子转移机制,用于离子 (丁) 供体的自我交换
Sergiy V Rosokha1, Jian-Ming Lü, Marshall D Newton
1Department of Chemistry, University of Houston, Texas, 77204, USA.
Journal of the American Chemical Society
|May 19, 2005
概括
盐的p-丁基离子 (DNB(-)) 的电子转移率取决于离子配对. 分离离子对 (SIP) 显示更快的速率,而接触离子对 (CIP) 显示较慢的动力学受到阳离子运动的影响.
科学领域:
- 电化学 电化学 电化学
- 化学物理 化学物理
- 晶体学 晶体学是指结晶学.
背景情况:
- 了解电子转移动力学在化学和生物学中至关重要.
- 离子对相互作用显著影响反应活性和反应途径.
- 之前的研究对不同类型的离子对缺乏明确的结构和运动数据.
研究的目的:
- 量化评估复杂的平衡和p-dinitrobenzene基离子 (DNB(-) 的盐的内在电子转移速率.
- 为了将分离 (SIP) 和接触 (CIP) 离子对的X射线结构与它们的光谱特征相关联.
- 阐明不同离子对配置中控制电子转移的机制.
主要方法:
- 用X射线晶体学来确定离子对的确定的结构.
- 光谱表征 (UV-NIR,ESR) 用于分析离子对的特性.
- 动力学研究,以评估电子转移速率和平衡.
主要成果:
- 三类离子对 (S,M,C) 根据K(+) 与聚联体的结合被确定.
- 类S:SIP电子转移速率与自由离子相似,不受内部离子距离 (>6 Å) 的影响.
- 类M:CIP和SIP之间的动态平衡;尽管度低,但SIP主导动力学.
- 类C:SIP利率受到CIP-SIP互换的限制;自我交换通过CIP进行.
- 马库斯/苏丁理论准确地描述了SIP速率;CIP速率需要涉及离子移动性的关联机制.
结论:
- 离子配对结构决定了电子转移机制和速率.
- 分离离子对 (SIP) 促进了更快的电子转移,而接触离子对 (CIP) 则表现出较慢的,依赖于阴离子移动性的动力学.
- 该研究为了解离子对对电子转移的影响提供了定量基础.
更多相关视频
11:04Ion Mobility-Mass Spectrometry Techniques for Determining the Structure and Mechanisms of Metal Ion Recognition and Redox Activity of Metal Binding Oligopeptides
Published on: September 7, 2019
07:24Quantitative Atomic-Site Analysis of Functional Dopants/Point Defects in Crystalline Materials by Electron-Channeling-Enhanced Microanalysis
Published on: May 10, 2021
相关概念视频
Ionic Bonding and Electron Transfer
Ions are atoms or molecules bearing an electrical charge. A cation (a positive ion) forms when a neutral atom loses one or more electrons from its valence shell, and an anion (a negative ion) forms when a neutral atom gains one or more electrons in its valence shell. Compounds composed of ions are called ionic compounds (or salts), and their constituent ions are held together by ionic bonds: electrostatic forces of attraction between oppositely charged cations and anions.
Valence Bond Theory
Coordination compounds and complexes exhibit different colors, geometries, and magnetic behavior, depending on the metal atom/ion and ligands from which they are composed. In an attempt to explain the bonding and structure of coordination complexes, Linus Pauling proposed the valence bond theory, or VBT, using the concepts of hybridization and the overlapping of the atomic orbitals. According to VBT, the central metal atom or ion (Lewis acid) hybridizes to provide empty orbitals of suitable...
Induced Electric Dipoles
A permanent electric dipole orients itself along an external electric field. This rotation can be quantified by defining the potential energy because the external torque does work in rotating it. Then, the potential energy is minimum at the parallel configuration and maximum at the antiparallel configuration. While the former is a stable equilibrium, the latter is an unstable equilibrium.
Since the absolute value of potential energy holds no physical meaning, its zero value can be chosen as per...
Since the absolute value of potential energy holds no physical meaning, its zero value can be chosen as per...
Ion Exchange
Ion exchange chromatography separates charged molecules from a solution by reversibly exchanging them with mobile, or 'active', ions associated with the oppositely charged stationary phase. This method can be used to separate ions, soften and deionize water, and purify solutions. The polymers comprising the ion-exchange column are high-molecular-weight and chemically stable polymers, crosslinked to be porous and essentially insoluble. They are also functionalized with either acidic or basic...
Electrochemical Systems
Electrochemical systems provide a fascinating insight into the dynamic interplay of charged species within various phases. One notable example is the interaction between a membrane permeable to K⁺ ions but not to Cl⁻ ions, separating an aqueous KCl solution from pure water. As K⁺ ions diffuse through the membrane, they generate net charges on each phase, leading to a potential difference between them.Similarly, when a piece of Zn is immersed in an aqueous ZnSO₄ solution, the Zn metal, composed...
The Electrical Double Layer
In the region where two bulk phases meet, an intricate electric charge distribution arises due to charge transfer, ion adsorption, molecular orientation, and charge distortion. This complex distribution is commonly referred to as the electrical double layer.When a solid electrode interfaces with ions in an electrolyte solution, the speed of electron transfer dictates the rates of oxidation and reduction. The electrode acquires a charge through the escape of atoms into the solution as cations or...
