关键词: 核磁共振谱, 化学位移, 距边矢量, 三键数, 烷烃

Abstract: A set of novel atom descriptor called as Distance-Edge Vector (μ) was developed, which expressed the total information about the carbon atom disposition with respect to one another in alkanes. By taking the Distance-Edge Vector(μ) and the path counts of length three C-C bonds (P₃) apart from the given carbon atom as parameters, the multiple linear regression analysis between these parameters and the ¹³C NMR chemical shifts of all alkanes bearing one to nine carbon atoms (64 compounds including 326 different chemical shifts for topologically nonequivalent positions in alkanes) was curried out. The obtained result was:the standard deviation S is only 0.9629ppm and the correlation coefficient R is 0.9957. Using the linear regression analysis equation, we got precision of prediction:for 83% (90% and 95%) of the shifts, the difference between the experimental and predicted values was less than 1.0ppm (1.5ppm and 2.0ppm respectively).

Key words: ¹³C NMR Spectrometry, Carbon atom chemical shift, Distance-Edge Vector, Path counts of length three bounds (P₃), Alkanes