乌拉和胺在水溶液中的单一兴奋状态行为:对11种乌拉衍生物的综合实验和计算研究
Thomas Gustavsson1, Akos Bányász, Elodie Lazzarotto
1Laboratoire Francis Perrin, CEA/DSM/DRECAM/SPAM - CNRS URA 2453, CEA Saclay, Gif-sur-Yvette, France. thomas.gustavsson@cea.fr
Journal of the American Chemical Society
|January 13, 2006
概括
乌拉衍生物的兴奋状态寿命使用超快光谱法测量. 在C5位置的替代物影响兴奋状态行为和寿命,在5-替代化合物中观察到更长的寿命.
科学领域:
- 摄影化学的使用.
- 计算化学的计算化学
- 分子光谱学 分子光谱学
背景情况:
- 乌拉及其衍生物在核酸和制药中具有根本性的作用.
- 了解它们的兴奋状态动态对于光化学和光生物学至关重要.
- 之前的研究表明, uracil 激发状态的快速衰变途径.
研究的目的:
- 研究 uracil,thymine 和相关衍生物的兴奋状态特性和寿命.
- 阐明C5替代剂在调节兴奋状态动态中的作用.
- 为了将计算预测与实验光谱数据相关联.
主要方法:
- 稳态和时间分辨率光谱学,包括五秒钟光升级转换.
- 时间依赖密度函数理论 (TD-DFT) 用 PBE0 函数进行计算.
- 可极化连续模型 (PCM) 用于水溶液模拟.
- 形交叉分析的CASSCF计算.
主要成果:
- 大多数乌拉衍生物的兴奋状态寿命是超快的 (<100 fs).
- 5替代衍生品表现出更复杂的,比比指数的衰变和更长的寿命.
- 计算光谱与实验数据保持一致.
- 在S(0)/S(1) 圆交点处的能量屏障随着C5的替代而增加 (乌拉<提胺<5-甲).
结论:
- 圆交点S(0)/S(1) 和C5替代子运动控制着激发状态衰变路径.
- 在C5位置的替换显著影响激发状态的寿命.
- 计算方法准确地预测了激发状态生命周期中的光谱特性和趋势.
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