【摘要】 以取代苯苯环碳原子化学位移为依据,用曾经设定并初步证实的甲基诱导效应和共轭效应参数,讨论了甲基取代基的诱导效应、共轭效应及定位效应.化学位移值表示的诱导效应参数表明甲基具有吸电子诱导效应,经校正后的化学位移值表示的共轭效应参数表明甲基具有微弱的给电子共轭效应,甚至其共轭效应有可能正处于给电子和吸电子的临界状态,总之相对于氢原子,甲基具有吸电子效应.甲基有较强的对位定位效应和较弱的邻位定位效应,在适宜条件下间位也有可能发生取代反应.更多还原

【Abstract】 According to the（）¹³CNMR chemical shifts of substituted benzene,conjugative effect parameter and inductive effect parameter are established.Parameters based on chemical shift indicate that methyl is a substituent with electron-withdrawing inductive effect and poor electron-donating conjugative effect.Perhaps its conjugative effect is on critical point.Methyl is electron-withdrawing for benzene relative to H.Otherwise,methyl has strong pposition and weak o-position orientation effect.Substitution reaction can take place on m-position under appropriate conditions.更多还原