摘要
由于影响^(31)P-NMR化学位移变化的结构因素极其复杂,科学家们试图建立一个统一的理论模型来说明各类磷化合物的^(31)P-NMR没有获得成功。我们在总结归纳自己200个和文献近千个实验数据的基础上,分析比较了有机磷酸酯结构类型与^(31)P-NMR化学位移的关系。首次观察到^(31)P-NMR化学位移可用5条经验规律来说明。研究表明:有机磷化合物的^(31)P-NMR化学位移及其经验规律是由核外电子云球对称性(而非电子云密度)决定的。
A great progress has been gained in the research field of NMR shielding effects.Many authors have attempted to create an unified empirical or theoretical foundation for^(31)P-NMR chemical shifts in all classes of different structure of organophosphorus compounds.It is not surprising that no one has met with success, since the factors affecting ^(31)P-NMR chemi-cal shifts are very complex. The substituent effects on ^(31)P-NMR chemical shifts, as we found, are determined by fiveempirical rules. The proposed rules are based on the fact that the shielding (upfield shift) of reso-nance nucleus is governed by the spherical symmetry of the electron cloud around the nucleus.
出处
《军事医学科学院院刊》
CSCD
北大核心
1993年第1期1-6,共6页
Bulletin of the Academy of Military Medical Sciences
关键词
NMR
化学位移
屏蔽效应
磷31
~31P-NMR
chemical shifts
shielding effects
spherical symmetry of electron cloud around nucleus
