可以分离的dialkylsilylene的基离子
1Department of Chemistry, Graduate School of Science, Tohoku University, Aoba-ku, Sendai 980-8578, Japan.
Journal of the American Chemical Society
|March 13, 2003
概括
研究人员通过减少一个dialkylsilylene产生了第一个在溶液中持久的西基离子. 这种新型的基离子在低温下稳定,但在室温下迅速分解.
科学领域:
- 有机化学 有机化学
- 极端阳离子化学 极端阳离子化学
- 频谱学是一种光谱学.
背景情况:
- 基基烯是反应性中间体.
- 溶液中持久的烯基基离子以前没有被分离或描述.
- 了解烯衍生物的电子结构和稳定性至关重要.
研究的目的:
- 在溶液中合成和表征第一个持久的烯基基离子.
- 为了研究生成的烯基基离子的稳定性和电子性质.
- 通过光谱方法阐明溶液中的基离子的性质.
主要方法:
- 在DME中使用金属4,4'-di(tert-butyl) 双化物减少2,2,5,5-[tetrakis(trimethylsilyl) ]-1-silacyclopentane-1,1-diyl (1).
- 电子自旋共振 (ESR) 谱学用于表征.
- 变量温度研究以评估稳定性.
主要成果:
- 在溶液中生成第一个持久的烯基基离子 (2).
- 基离子2在DME中表现出在-70°C的稳定性,在室温下半衰期约为20分钟.
- 据ESR数据 (g因子和29Si超精细分裂) 显示,未配对的电子位于双价的空置3pπ轨道中,独立于极地DME的对抗作用.
结论:
- 在溶液中成功生成和表征持久的基离子,这代表了化学的重大进步.
- 电子结构表明未配对的电子位于双价原子上.
- 观察到的稳定性和光谱性质为在极性溶剂中烯基基离子的行为提供了洞察力.
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