关于电子激发的黄和5-甲基黄的超快放松动态的见解
Wenping Wu1,2, Baihui Feng1,2, Yuhuan Tian1,2
1State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, Liaoning 116023, China.
The journal of physical chemistry. A
|October 4, 2024
概括
通过使用 Femtosecond 时间解析的光电子谱学研究了furfural 和 5-methylfurfural 的超快放松动态. 研究揭示了明显的衰变路径和甲基替代对激发状态动态的影响.
科学领域:
- 物理化学 物理化学
- 摄影化学的使用.
- 分子光谱学 分子光谱学
背景情况:
- 黄及其衍生物是重要的化合物,在生物燃料和制药中具有应用.
- 了解它们的兴奋状态动态对于控制光化学反应和设计新材料至关重要.
- 有机分子中的超快速过程在各种化学和生物现象中起着关键作用.
研究的目的:
- 为了研究紫外线刺激后的furfural和5-methylfurfural的超快放松动态.
- 为了阐明这些分子在激发电子状态中的波长依赖的衰变机制.
- 探索甲基替代对兴奋状态失活路径的影响.
主要方法:
- 用5秒时间分辨率光电子光谱学 (TRPES) 来探测动态.
- 使用各种紫外线波长进行了探针实验.
- 对时间解析的光电子光谱的详细分析提供了关于衰变寿命和途径的见解.
主要成果:
- 两个分子的光学明亮的S2 (1ππ*) 状态的寿命为数百 femtoseconds.
- 显著的禁用通道包括环打开和环破裂.
- 从S2状态到S1 (1nπ*) 状态的小内部转换路径被确定,S1状态通过系统间交叉到三重状态在2.52.8 ps中衰减.
结论:
- 这项研究揭示了furfural和5-methylfurfural中复杂的兴奋状态动态,涉及多个放松通路.
- 内部转换到S1状态和随后的系统间交叉是重要的停用路径.
- 甲基替代影响了兴奋状态衰变动态,提供了对结构-性质关系的见解.
相关概念视频
00:52¹H NMR of Conformationally Flexible Molecules: Temporal Resolution
811
At room temperature, the chair conformer of cyclohexane undergoes rapid ring flipping between two equivalent chair conformers at a rate of approximately 105 times per second. These two chair conformers are in equilibrium. The rapid ring flipping results in the interconversion of the axial proton to an equatorial proton and an equatorial to the axial proton. Such interconversions are too rapid and cannot be detected on the NMR timescale. Hence, the NMR spectrometer cannot distinguish between the...
811
01:29UV–Vis Spectroscopy: Woodward–Fieser Rules
23.9K
UV–Visible absorption spectra of conjugated dienes arise from the lowest energy π → π* transitions. The light-absorbing part of the molecule is called the chromophore, and the substituents directly attached to the chromophore are called auxochromes. A strong correlation exists between the absorption maxima, λmax, and the structure of a conjugated π system. The Woodward–Fieser rules predict the value of λmax for a given...
23.9K
01:24IR Spectroscopy: Molecular Vibration Overview
2.0K
When Infrared (IR) radiation passes through a covalently bonded molecule, the bonds transition from lower to higher vibrational levels. The fundamental vibrational motions that result in infrared absorption can be classified as stretching or bending vibrations.
Stretching vibrations are vibrational motions that occur along the bond line, changing the bond length or distance between two bonded atoms. They are further distinguished as symmetric or asymmetric. In symmetric stretching, the...
Stretching vibrations are vibrational motions that occur along the bond line, changing the bond length or distance between two bonded atoms. They are further distinguished as symmetric or asymmetric. In symmetric stretching, the...
2.0K
01:29IR and UV–Vis Spectroscopy of Aldehydes and Ketones
5.3K
Infrared spectroscopy, also known as vibrational spectroscopy, is mainly used to determine the types of bonds and functional groups in molecules. In aldehydes and ketones, the carbonyl (C=O) bond shows an absorption around 1710 cm-1. The C=O bond vibration of an aldehyde occurs at lower frequencies than that of a ketone. In addition to the C=O absorption in an aldehyde, the aldehydic C–H bond also gives two peaks in the 2700–2800 cm-1 range. This absorption, coupled with the...
5.3K
01:28Atomic Nuclei: Types of Nuclear Relaxation
268
Nuclear relaxation restores the equilibrium population imbalance and can occur via spin–lattice or spin–spin mechanisms, which are first-order exponential decay processes.
In spin–lattice or longitudinal relaxation, the excited spins exchange energy with the surrounding lattice as they return to the lower energy level. Among several mechanisms that contribute to spin–lattice relaxation, magnetic dipolar interactions are significant. Here, the excited nucleus transfers...
In spin–lattice or longitudinal relaxation, the excited spins exchange energy with the surrounding lattice as they return to the lower energy level. Among several mechanisms that contribute to spin–lattice relaxation, magnetic dipolar interactions are significant. Here, the excited nucleus transfers...
268
01:25Deactivation Processes: Jablonski Diagram
599
Luminescence, the emission of light by a substance that has absorbed energy, is a process that involves the interaction of molecules with light. The energy-level diagram, or Jablonski diagram, is a graphical representation of these interactions, illustrating the various states and transitions a molecule can undergo. In a typical Jablonski diagram, the lowest horizontal line represents the ground-state energy of the molecule, which is usually a singlet state. This state represents the energies...
599