供电子基又叫electron donating group（EDG） 吸电子基又叫electron withdrawing group（EWG） 是一个通过改变电子密度影响化合物反应活性的重要因素。 可以简单以两种方式来 判断一个基团是EDG还是EWG。 ----------------------------------------------------------------------------------- 先讲第 ...

2024年7月12日 · 另外，根据与芳环作用的电子效应和共轭效应，又可以分为EDG（electron donating group）即供电子基团和EWG（electron withdrawing group）即拉电子或吸电子基团。 一般情况下，含有EDG的芳环，在邻对位发生亲电反应；而含有EWG的芳环，在间位发生亲电反应。

An electron donating group (EDG) or electron releasing group (ERG, Z in structural formulas) is an atom or functional group that donates some of its electron density into a conjugated π system via resonance (mesomerism) or inductive effects (or induction)—called +M or +I effects, respectively—thus making the π system more nucleophilic. [1 ...

EWG can be recognised either by the atom adjacent to the π system having several bonds to more electronegative atoms, or, having a formal +ve or δ +ve charge, eg: -CO 2 R, -NO 2

An electron-withdrawing group (EWG) is a group or atom that has the ability to draw electron density toward itself and away from other adjacent atoms. [1] This electron density transfer is often achieved by resonance or inductive effects.

2024年3月18日 · 供电子基又叫electron donating group（EDG）-表现电负性； 吸电子基又叫electron withdrawing group（EWG）-表现正电性；是一个通过改变电子密度影响化合物反应活性的重要因素。 富电子环在环中包含电子贡献官能…

2023年4月5日 · The main difference between EDG and EWG is their effect on the electron density of a molecule. EDGs increase electron density in the molecule, while EWGs decrease electron density.

2024年6月3日 · The terms EDG and EWG are used in organic chemistry to describe how a substituent (an atom or group of atoms) affects the electron density around a molecule. EDG stands for the electron-donating group, while EWG stands for the electron-withdrawing group.

2023年12月6日 · EDG stands for Electron Donating Group, while EWG stands for Electron-Withdrawing Group. These groups are functional groups that can influence the behavior of a molecule by donating or withdrawing electrons. Their effects on reactivity, resonance, and molecular properties are key to understanding their significance.

ERG (EDG): 给电子基团，EDG可以使苯环活化，对邻对位的活化作用大于间位，所以为邻对位定位基团。 EWG: 吸电子基团，EWG使苯环钝化，其对邻对位的钝化作用大于间位，所以为间位定位基团。