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乙烯酸的乙烯酸的溶液结构的环坦,环,乙和基. 三重离子和较高的酸盐复合物
Kristopher J Kolonko1, Margaret M Biddle, Ilia A Guzei
1Department of Chemistry, University of Wisconsin, Madison, Wisconsin 53706, USA.
乙烯酸在各种溶剂中表现出多样化的结构,包括四聚体和二聚体. 像HMPA和氨酸这样的添加剂会影响这些结构,形成单体,三重离子和四重离子,并观察到异构体特定的行为.
科学领域:
- 有机金属化学 有机金属化学
- 溶液状态化学 溶液状态化学
- 频谱学是一种光谱学.
背景情况:
- 乙酸是有机合成中的关键中间体.
- 了解它们的聚合状态是控制反应性的关键.
- 以前的研究表明结构不同,但混合溶剂的详细表征是有限的.
研究的目的:
- 为了研究不同溶剂混合物中乙烯酸盐的聚合结构.
- 阐明像HMPA和胺类添加剂对酸盐聚合物的影响.
- 为了比较特定乙烯酸盐的Z和E异构体的结构性行为.
主要方法:
- 在低温下 (-110~-150°C) 进行多核核核磁共振光谱.
- 涉及四基 (THF) /二甲基乙烯 (Et2O) 混合物的研究.
- 使用六甲基酸 (HMPA),四甲基乙烯胺 (TMEDA) 和五甲基二乙烯胺 (PMDTA) 的添加剂效应的研究.
- 使用乙烯酸盐制备和特征较高的化物种.
主要成果:
- p-烯酸盐和简单酸乙烯酸盐采用THF/Et2O和THF/Et2O-HMPA的四度结构.
- 1,3-bis-(4-fluorophenyl)-2-propanone乙烯酸盐 (5F-Li) 的Z和E异构体表现出不同的聚合行为.
- Z-5F-Li存在于二甲基以太和THF/以太中的二极体,在添加氨基或HMPA时形成单体,三重离子和四重离子.
- 即使在HMPA中,E-5F-Li在THF/乙烯中仍然是二度的,在二甲基乙烯中仍然是四度的,对单体化有抗性.
结论:
- 溶剂组成和添加剂显著影响乙烯酸聚合状态.
- 在5F-Li.Li的Z和E异构体之间存在明显的结构偏好.
- 六种不同的酸盐结构 (四聚,二聚,单聚,三离子,四离子) 为5F-Li同位素的特征,突出了酸盐化学的复杂性.
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