摘要
以单取代苯为模型,假定间位共轭效应受阻,诱导效应在共轭体系中的传递因子为1/2,则基团的共轭效应参数:R_C=0.05(△δ_P-△δ_m)或R_C=0.05(△δ_P-△δ_m)△δ_P和△δ_m分别表示单取代苯对位和间位的^(13)C NMR化学位移相对于未取代母体增量,δ_P和δ_m分别为单取代苯对位和间位的^(13)C NMR化学位移。用上式计算了559个基团的共轭效应参数,其结果与文献报道值颇为一致,且呈明显的变化规律。
Using monosubstituted benzene as a model and presuming: (1) the conjugative effect of meta - position is prohibited; (2) the transmit factor of induction effect in the conjugative system is 1/2, the experimental formula for the conjugative effect parameters can be expressed as follows:
Where Δδp and Δδm refer to the deviations of 13C NMR chemical shifts of para - and meta - positin of monosubstituted benzenes with respect to unsubsdtuted parent respectively. δp and δm refer to the 13C NMR chemical shifts for para - position and meta - position respectively. Using the formula, conjugative effects parameters for 559 groups are calculated, and the results agree well with the observed values in the literature.
出处
《有机化学》
SCIE
CAS
CSCD
北大核心
2000年第2期237-242,共6页
Chinese Journal of Organic Chemistry
关键词
基团
共轭效应参数
有机化学
单取代苯
group, conjugative effect parameter, (13)~C NMR chemical shift
