脉冲X射线捕捉到的快速兴奋状态结构重组
Lin X Chen1, Guy Jennings, Tao Liu
1Chemistry Division and Materials Science Division, Argonne National Laboratory, Argonne, IL 60439, USA. lchen@anl.gov
Journal of the American Chemical Society
|September 5, 2002
概括
研究人员使用X射线来描述溶液中铜复合物的光发光激发状态. 这项研究提供了在纳米秒时间尺度上的流体环境中分子激发状态的第一个X射线数据.
科学领域:
- 摄影化学的使用.
- 无机化学 无机化学
- 射线光谱 X射线光谱
背景情况:
- 金属到质电荷转移 (MLCT) 激发状态在光化学中至关重要.
- 在溶液中理解这些状态的结构动态是具有挑战性的.
- 之前的研究缺乏关于流体介质中过渡激发状态的直接结构信息.
研究的目的:
- 为了结构性地表征纳秒MLCT激发状态的[Cu(I) ((dmp) 2) ((BArF) 在烯.
- 为了研究光刺激时发生的几何变化.
- 为在溶液中提供分子激发状态的第一个X射线结构数据.
主要方法:
- 可见光光激发的[Cu (I) (dmp) ]2 (BArF) 的光刺激.
- 时间分辨率的X射线吸收光谱使用脉冲X射线.
- 分析X射线数据以确定激发状态的结构参数.
主要成果:
- 观察到光发光的MLCT激发状态,寿命为98 ± 5 ns.
- 激发状态具有五坐标的铜中心 (Cu (II) 在Cu (I) 几何中) 与 Cu-N 键长度增加 (平均增加0.07 Å).
- 坐标几何变化为扭曲的三角形双金字塔.
结论:
- 短暂形成的五坐标MLCT状态是光发光,表明吸收和发射状态的不同几何形状.
- 这项工作介绍了纳米秒时间尺度上的流体溶液中分子激发状态的第一个X射线表征.
- 这些发现为溶液中兴奋状态的结构动态提供了新的见解.
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