基团共轭效应参数

以单取代苯为模型，假定间位代轭效应受阻，诱导效应在共轭体系中的传递因子为1/2，则基因的共轭效应参数：Rc=0.05(△δp-△δm)或Rc=0.05(δp-δm)△δp和△δm分别表示单取代苯对位和间位的^1^3CNMR化学位移相对于未取代母体增量，δp和δm分别为单取代苯对位和间位的^1^3CNMR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。

Conjugative effect parameters of groups

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 △δp and△δm refer to the deviations of ^1^3C NMR chemical shifts of para - and meta - positin of monosubstituted benzenes with respect to unsubstituted parent respectively. δp and δm refer to the ^1^3C NMR chemical shifts for para - position and metal - 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.