多环芳烃^(13)C-NMR化学位移的理论摸拟

Theoretical Prediction of ^(13)C-NMR Chemical Shifts on PAH

本文利用ＣＮＤＯ方法对十个多环芳烃化合物的^（１３）Ｃ－ＮＭＲ的化学位移进行了理论上的计算，并提出了一个联系分子电荷密度、键级和键长等多数的半经验公式。同时利用逆磁环电流，顺磁环电流，湾区推斥效应和迫位效应的影响，又对多环芳烃的化学位移进行了校正，从而使得理论计算与实验值吻合得很好，通过时多环芳烃的^（１３）Ｃ－ＮＭＲ化学位移的回归分析表明：回归系数达到０．９５，较好地反映了多环芳烃^（１３）Ｃ－ＮＭＲ化学位移与分子微观结构之间的关系。

A high accurate equation for the theoretical prediction of ￣(13)C-NMR Chemical Shift of 10 benzenoid parent polycyclic aromatic hydrocarbons(PAH) has been put forward in this paper.It is calculated by CNDO method.The theoretical prediction made by the equation considered fully the shielding of various ring currents and the effect of different stereo structures and give much better results than previous works. The correlation coefficient calculated and observed ￣(13)C-NMR chemical shifts is over 0. 95. Therefore,it well reflects the relationship between molecular microstructure and ￣(13)C-NMR chemical shifts of PAH.