^(19)F NMR化学位移经验公式的影响因素

Influence Factors of the Empirical Formulas of ^(19)F NMR Chemical Shift

化学位移是核磁共振技术的重要参数,目前对~1H NMR、^(13)C NMR已提出一系列估算化学位移的经验公式,但^(19)F NMR化学位移规律研究报道则较少,以δ=B+∑△i+C化学位移通式为基础,分析屏蔽常数对化学位移的作用,并针对^(19)F原子,分析了氟的电子云密度、立体效应、溶剂效应、氢键、标准、浓度和温度等影响因素,对^(19)F NMR化学位移经验公式的提出提供理论依据。

Chemical shift is an important parameter in nuclear magnetic resonance technology. Currently,a series of empirical formulas for estimating chemical shift were reported on^1H NMR, ^（13）C NMR,but that on ^（19）F NMR were less.On the basis of the formula：δ= B＋Σ△i＋C,the effect of the screening constant on chemical shift was analyzed.Aimed at ^（19）F atom,the effects of the electron cloud density,the stereo effect,the solvent effect,the hydrogen bond,the standard,concentration and the temperature of fluorine were analyzed.The method provides theoretical basis for the empirical formulas of ^（19）F NMR chemical shift.