作为分子系统中电荷分离的方便报告器的CN拉伸频率
Yuyao Yang1, Jingsong Liu2, Ran-Ran Feng1
1Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.
The journal of physical chemistry. B
|August 1, 2023
概括
在不同的分子中,基组电荷和拉伸频率之间存在线性关系. 这一发现有助于理解捐赠者-接受器系统和光激发的醇衍生物中的电荷转移.
科学领域:
- 计算化学的计算化学
- 频谱学是一种光谱学.
- 有机电子 有机电子
背景情况:
- 之前的研究确定了结构相似的化合物中酸电荷 (qCN) 和拉伸频率 (νCN) 之间的线性关系.
- 单一的线性 νCN-qCN 关系对结构不同烯的适用性仍未得到证实.
研究的目的:
- 调查一系列含有亚酸盐的分子是否存在 νCN 和 qCN 之间的通用线性关系.
- 将这种关系应用于分析光激发的醇衍生物中的电荷转移现象.
主要方法:
- 对众多酸分子的qCN值的计算.
- 在各种实验条件下,对跨越200cm-1光谱范围的 νCN值进行分析.
- 导出线性关系的应用,以研究5 - 英和6 - 英中的电荷转移.
主要成果:
- 确定了 νCN 与 qCN 的一致的线性依赖性,其确定的斜率为 637 ± 30 cm-1 / 电荷.
- 这项研究证实了这种线性关系的实用性,用于描述捐赠者-接受者系统中的电荷转移.
- 印衍生物的光刺激分析表明,电荷转移或La状态的光辐射.
结论:
- 这些发现建立了一个广泛适用的线性 νCN-qCN 关系,对计算和实验化学家有价值.
- 这种关系为含有亚基的分子中电子特性和电荷转移机制提供了洞察力.
- 这项研究表明了这种关系在理解有机分子激发状态动态的实际应用.
相关概念视频
IR Frequency Region: Alkyne and Nitrile Stretching
907
Both alkyne (C≡C) and nitrile (C≡N) functional groups contain triple bonds and show stretching absorptions around the wavenumber range of 2100 to 2300 cm−1 in the diagnostic region of the IR spectra.
Comparing the stretching vibrational frequency of C≡C triple bonds with that of double and single bonds, it is evident that C≡C triple bonds exhibit a higher stretching frequency than C=C double and C–C single bonds. Similarly, the C≡N triple bond...
Comparing the stretching vibrational frequency of C≡C triple bonds with that of double and single bonds, it is evident that C≡C triple bonds exhibit a higher stretching frequency than C=C double and C–C single bonds. Similarly, the C≡N triple bond...
907
IR Spectroscopy: Hooke's Law Approximation of Molecular Vibration
1.4K
A covalently bonded heteronuclear diatomic molecule can be modeled as two vibrating masses connected by a spring. The vibrational frequency of the bond can be expressed using an equation derived from Hooke's law, which describes how the force applied to stretch or compress a spring is proportional to the displacement of the spring. In this case, the atoms behave like masses, and the bond acts like a spring.
According to Hooke's law, the vibrational frequency is directly proportional to...
According to Hooke's law, the vibrational frequency is directly proportional to...
1.4K
IR Absorption Frequency: Delocalization
838
Electron delocalization refers to the distribution of electrons across multiple atoms within a molecule rather than being confined to a single atom or bond. This phenomenon is common in systems with conjugated bonds—structures where alternating single and double bonds allow π-electrons to move freely across the network. The movement of electrons stabilizes the molecule and can affect various chemical properties, including vibrational frequencies observed in IR spectroscopy.
In IR...
In IR...
838
¹H NMR: Interpreting Distorted and Overlapping Signals
1.1K
Spin systems where the difference in chemical shifts of the coupled nuclei is greater than ten times J are called first-order spin systems. These nuclei are weakly coupled, and their chemical shifts and coupling constant can generally be estimated from the well-separated signals in the spectrum.
As Δν decreases and the signals move closer, the doublets appear increasingly distorted. The intensities of the inner lines increase at the cost of those of the outer lines as the signals are...
As Δν decreases and the signals move closer, the doublets appear increasingly distorted. The intensities of the inner lines increase at the cost of those of the outer lines as the signals are...
1.1K
¹³C NMR: ¹H–¹³C Decoupling
1.1K
The probability of having two carbon-13 atoms next to each other is negligible because of the low natural abundance of carbon-13. Consequently, peak splitting due to carbon-carbon spin-spin coupling is not observed in spectra. However, protons up to three sigma bonds away split the carbon signal according to the n+1 rule, resulting in complicated spectra.
A broadband decoupling technique is used to simplify these complex, sometimes overlapping, signals. Broadband decoupling relies on a...
A broadband decoupling technique is used to simplify these complex, sometimes overlapping, signals. Broadband decoupling relies on a...
1.1K
IR Spectrum Peak Splitting: Symmetric vs Asymmetric Vibrations
1.1K
Identical bonds within a polyatomic group can stretch symmetrically (in-phase) or asymmetrically (out-of-phase). Similar to hydrogen bonding, these vibrations also influence the shape of the IR peak. Generally, asymmetric stretching frequencies are higher than symmetric stretching frequencies. For example, primary amines exhibit two distinct IR peaks between 3300–3500 cm−1 corresponding to the symmetric and asymmetric N-H stretching, while secondary amines exhibit a single...
1.1K


