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Updated: Jun 29, 2026
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Determination of the Gas-phase Acidities of Oligopeptides
Published on: June 24, 2013
炭酸的酸度:一个反驳和重新定义
1Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, 16610 Praha 6, Czech Republic.
Journal of the American Chemical Society
|September 27, 2001
概括
碳氧酸的酸度源于低能离子,挑战了以前的理论. 酸和离子中的共振起着作用,特别是在水中,但静电电位是关键.
科学领域:
- 物理化学 物理化学
- 量子化学 是一个量子化学.
- 理论化学 理论化学
背景情况:
- 最近的一种理论将碳酸酸的酸性归因于高分子能量和静电潜力,淡化了离子共振稳定.
- 这种观点表明,酸性源于酸分子的能量,而不是离子稳定.
研究的目的:
- 通过研究相反的过程来修订碳酸电离的理论:甲酸的质子化.
- 为了比较碳素酸的酸度与模型化合物,如2,2,2-三乙醇和参考离子,如甲酸盐.
- 阐明静电电位和共振对碳酸和相关化合物的酸度的贡献.
主要方法:
- 在MP2/6-31++G(2d,p) 级使用了ab initio计算来研究甲酸盐离子的质子化.
- 采用了使用实验性形成和计算能量来评估离子稳定性的异体反应.
- 研究了像2,2,2-三乙醇这样的模型化合物来隔离共振效应.
主要成果:
- 计算表明,碳酸的酸度主要是由于它们的阳离子的低能量,这与之前的理论相矛盾.
- 阳离子的静电潜力被确定为酸度的一个重要因素.
- 发现,在酸分子及其离子中的共振效应,与气相中的酒精相比,酸度增强的贡献不到一半,但在水溶液中超过一半.
结论:
- 碳酸酸的酸度基本上与它们的结合离子的稳定性 (低能) 有关.
- 阳离子的静电潜力是酸度的关键决定因素.
- 虽然共振有助于增加酸度,但其相对重要性在气相和水溶液之间有所不同,静电因素在气相中占主导地位.
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