超电子捐赠群对替代的化酸离子电子结构的影响
Arthur H Winter1, Daniel E Falvey, Christopher J Cramer
1Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742-2021, USA.
Journal of the American Chemical Society
|August 5, 2004
概括
电子捐赠替代物可以使三重体状态成为离子的基本状态. 这项研究基于替代效应确定了两个不同的低能三重状态,n,pi和pi,pi.
科学领域:
- 计算化学是一种计算化学.
- 量子化学是一种量子化学.
- 有机化学 有机化学
背景情况:
- 酸离子是反应性中间体.
- 了解它们的电子状态对于反应机制至关重要.
研究的目的:
- 为了研究替代效应对单元-三元能量差距在meta-substituted酸离子.
- 描述低三重状态的电子结构.
主要方法:
- 密度函数理论 (DFT) 使用 UB3LYP/6-31G ((d,p) 层次的理论.
- 对平衡几何学,科恩-沙姆轨道分布和穆利肯旋转密度的分析.
主要成果:
- 强烈的电子捐赠替代剂稳定了三重体状态,可能使其成为基本状态.
- 确定了两个不同的低能三重状态:n,pi和pi,pi.
- n,pi三重体 (简单和取电子/弱捐赠替代体) 具有一个共平面和一个直角单独占用的分子轨道.
- ,三胞胎 (强大的元捐赠者) 具有两个单独占用的分子轨道与环直角.
结论:
- 替代效应显著影响酸离子的基本状态.
- 三重离子的电子结构可以分为n,pi和pi,pi类型.
- 这些发现提供了对酸离子的电子特性和反应性的洞察.
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.
Lewis Structures of Molecular Compounds and Polyatomic Ions
To draw Lewis structures for complicated molecules and molecular ions, it is helpful to follow a step-by-step procedure as outlined:
Metal-Ligand Bonds
The hemoglobin in the blood, the chlorophyll in green plants, vitamin B-12, and the catalyst used in the manufacture of polyethylene all contain coordination compounds. Ions of the metals, especially the transition metals, are likely to form complexes.
In these complexes, transition metals form coordinate covalent bonds, a kind of Lewis acid-base interaction in which both of the electrons in the bond are contributed by a donor (Lewis base) to an electron acceptor (Lewis acid). The Lewis acid in...
In these complexes, transition metals form coordinate covalent bonds, a kind of Lewis acid-base interaction in which both of the electrons in the bond are contributed by a donor (Lewis base) to an electron acceptor (Lewis acid). The Lewis acid in...
Resonance and Hybrid Structures
According to the theory of resonance, if two or more Lewis structures with the same arrangement of atoms can be written for a molecule, ion, or radical, the actual distribution of electrons is an average of that shown by the various Lewis structures.
Resonance Structures and Resonance Hybrids
The Lewis structure of a nitrite anion (NO2−) may actually be drawn in two different ways, distinguished by the locations of the N–O and N=O bonds.
Resonance Structures and Resonance Hybrids
The Lewis structure of a nitrite anion (NO2−) may actually be drawn in two different ways, distinguished by the locations of the N–O and N=O bonds.
Electrophiles
This lesson explains the definition, classification, and characteristic features of an electrophile that are key features of nucleophilic substitution reactions. An analysis of their charge and orbital picture helps understand their reactivity for seeking electrons. Electrophiles can be classified into positive and neutral species. Other classes include free radicals and polar functional groups.
While a positive electrophile, like a proton, reacts due to its vacant, low-energy 1s orbital, the...
While a positive electrophile, like a proton, reacts due to its vacant, low-energy 1s orbital, the...
π Electron Effects on Chemical Shift: Overview
An applied magnetic field causes loosely bound π-electrons in organic molecules to circulate, producing a local or induced diamagnetic field over a large spatial volume. As the molecules tumble in solution, the field generated by π-electrons in spherical substituents results in a zero net field. However, the net field generated by π-electrons in non-spherical substituents is not zero. The effect of this induced field depends on the orientation of the molecule with respect to B0, resulting in...


