概括
在各种溶剂中研究了离子旋转. 结合,而不是溶剂特性,解释了它的快速旋转和依赖溶剂的行为.
科学领域:
- 物理化学 物理化学
- 解决方案化学 解决方案化学
- 频谱学是一种光谱学.
背景情况:
- 了解溶液中的离子动态对于各种化学过程至关重要.
- 氨离子的旋转相关时间会影响反应速率和分子相互作用.
- 以前的模型无法完全解释离子旋转所观察到的溶剂依赖性.
研究的目的:
- 在各种溶剂中确定氨离子 ((15) NH ((4) ((+)) 的旋转相关时间.
- 研究影响溶液中离子旋转动态的因素.
- 开发一个模型来解释观察到的旋转相关时间的溶剂依赖性.
主要方法:
- 使用的-15 (15N) 核磁共振 (NMR) 光谱.
- 测量了自旋格子放松时间 (T1) 和核Overhauser增强 (NOE).
- 从放松数据计算的旋转相关时间 (τc).
主要成果:
- 在不同的溶剂中,确定了15NH(4) ((+) 的旋转相关时间 (τc),从0.46到20皮秒不等.
- 在tc值中观察到显著的溶剂依赖.
- 发现溶剂极性,二极子瞬间,基本性,介电松和粘度无法解释观察到的tc变化.
结论:
- 氨离子的快速旋转及其对溶剂的依赖最好用涉及结的模型来解释.
- 具体来说,NH质子与无序的溶解中的多个溶剂分子的键结合解释了这些发现.
- 这突显了特定的溶解物-溶剂相互作用的重要性,比如结合,在确定离子动力学方面超过了散装溶剂特性.
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