六甲基基化物 (KHMDS):依赖溶剂的溶液结构
Jesse A Spivey1, David B Collum1
1Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853-1301, United States.
Journal of the American Chemical Society
|June 20, 2024
概括
使用NMR和DFT研究了六甲基化物 (KHMDS) 溶液的结构. 根据联体类型和度,联体协调会影响KHMDS的聚合,形成二聚体,单聚体和离子对.
科学领域:
- 有机金属化学
- 溶液状态化学
- 光谱学
背景情况:
- 六甲基基化物 (KHMDS) 是一种在有机合成中广泛使用的强型非核基.
- 了解KHMDS的溶液状态聚合和物种化对于控制其反应性至关重要.
- 之前的研究已经提出了各种聚合状态,但在不同体存在的情况下缺乏全面的分析.
研究的目的:
- 阐明KHMDS及其同位素标记变体的溶液结构和聚合行为 ([15N]KHMDS).
- 研究各种协调配体对KHMDS物种化的影响 (单体,二元,离子对).
- 将实验结果与理论计算联系起来,以更深入地理解KHMDS解法.
主要方法:
- 使用Si 29 NMR光谱和N - 29Si合探测KHMDS结构.
- 使用连续变化的方法来确定聚合状态.
- 密度函数理论 (DFT) 的计算被用于模拟溶解效应和能量学.
主要成果:
- 溶液中的KHMDS存在于二聚体,单聚体和离子对的形式,其分化是由联体类型和度决定的.
- 在特定条件下,弱协调联体有利于二聚体,而合联体可以导致单聚体或离子对.
- DFT计算通常与关于聚合物和溶酸盐的实验观测一致,尽管温度依赖性不同.
结论:
- KHMDS的聚合状态可以通过与各种配体的协调进行高度调整.
- 这项研究提供了KHMDS溶液行为的详细地图,对于优化其在合成中的使用至关重要.
- 联体协调,聚合和溶解之间的相互作用显著影响KHMDS的结构和反应性.
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