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取决于溶剂的超快光化学动力学N-甲基氧过度拥挤的烯分子电机
Connah J Harris1, Beatrice S L Collins1, Andrew J Orr-Ewing1
1School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, United Kingdom.
The journal of physical chemistry. A
|June 16, 2025
概括
这项研究研究了过度拥挤的烯分子电机,揭示了溶剂极性和粘度对它们的光异构化效率有重大影响. 这项研究强调了低量子产率 (0.4-8.7%),这是由于低效的激发状态动态.
科学领域:
- 光化学和分子动力学
- 超分子化学和纳米技术
背景情况:
- 过度拥挤的基因通过光化学和热过程作为旋转分子电机起作用.
- 现有的分子电机设计由于低光诱导异构化效率而受到影响.
- 超快光谱对于理解激发状态动态和光异构化机制至关重要.
研究的目的:
- 为了研究可见光激活过度拥挤的基电机与N-甲基氧醇功能上的光异构化机制.
- 探测溶剂极性和粘度对电机激发状态动态和异构化效率的影响.
- 为了确定研究的分子电机的异构化量子产量.
主要方法:
- 采用超快速时间分辨率光谱,包括短暂吸收和时间分辨率红外光谱 (TRIR).
- 在环素,DMSO和甲醇中检查了分子电机,以评估溶剂效应.
- 使用密度函数理论 (DFT) 和时间依赖的DFT (TD-DFT) 计算来建模潜在能量表面和分子几何.
主要成果:
- 确定了四个动态过程:兴奋状态放松 (<120 fs),黑暗状态减少 (0.5-14 ps) 和振动冷却 (10-15 ps).
- 观察到暗态衰变时间尺度取决于溶剂极性和粘度,粘度较高会增加激发状态寿命.
- 确定低量子收益率的异构化,范围从0.4%到8.7%,通过TRIR光谱分析证实.
结论:
- 溶剂特性极大地影响过度拥挤的烯分子电机的光异构化效率.
- 兴奋状态动态主要由S1状态控制,较高单元状态的参与最小.
- 该研究阐明了限制这些分子电机性能的关键因素,为未来的设计改进提供了见解.
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