1-(2-尼托) 乙烯的光解裂涉及两个并行路径,产品的释放速度受到常见半乙中间体分解的限制
John E T Corrie1, Andreas Barth, V Ranjit N Munasinghe
1National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, UK. jcorrie@nimr.mrc.ac.uk
Journal of the American Chemical Society
|July 10, 2003
概括
闪光光电解1 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 乙烯基乙烯的闪光光电解揭示了一种长寿命的半乙烯基中间体. 它的缓慢分解限制了产品的释放,与这种光化学反应中更快的酸中间体衰变形成对比.
科学领域:
- 摄影化学的使用.
- 有机化学 有机化学
- 频谱学是一种光谱学.
背景情况:
- 众所周知,1-(2-尼托菲尼尔) 乙烯经历光解分解.
- 了解反应机制和中间体对于合成应用至关重要.
研究的目的:
- 为了研究1 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 的闪光光光电解的反应机制.
- 描述光解分解过程中的中间体和速率限制步骤.
主要方法:
- 时间分辨率的里埃变换红外光谱 (FTIR) 光谱.
- 时间分辨率的紫外线可见 (UV-vis) 光谱学.
- 产品分析 产品分析
- 半经验性PM3和AMSOL计算
主要成果:
- 确定了一种长寿命的半乙中间体,其分解是限制产品释放的速度.
- 在pH 7.0.0下,乙酸中间体的衰变速度明显快 (5020s-1) 比产品释放速度快 (0.11s-1).
- 血的形成通过两个相互竞争的途径 (快速~80%,缓慢~20%),只有较小的途径与酸衰变有关.
- 计算研究表明,酸同位素的pKa影响路径分区.
结论:
- 1-(2-尼托菲尼尔) 乙烯乙烯的光解涉及到一个独特的,速度限制的半乙中间体.
- 竞争的反应通路和异构体的pKa在整体光解机制中发挥着关键作用.
- 这些发现与相关的2-二乙烯相反,突出了光化学中的结构特异性.
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