Conjugation effect is stronger than induction effect. When it is a halogen, conjugation effect is opposite to induction effect. As a result, the orientation effect is dominated by induction effect, and the induction effect is reflected in the passivation of the attached group. Conjugate effect, the one that takes out the lone pair is c, and the one that takes out the empty orbital is minus c. The induced effects, mainly look at electronegativity, and then look at hybrid forms. The higher the electronegativity, the higher the -i, the electron absorption effect of carbon atom sp hybrid > sp2 hybrid > sp3 hybrid.
Induced effect and conjugation effect are two separate and independent effects. In a system, two effects may coexist, not only one of them.
The induced effect is related to the electronegativity of the atom. Atoms or groups that are more electronegative than carbon can make electrons in the benzene ring move through the σ bond like substituents, that is, have the induced effect of electron absorption. Atoms or groups that are less electronegative than carbon cause electrons on the substituent to move towards the benzene ring through the σ bond, that is, they have the induced effect of electron absorption.
The conjugation effect is caused by the overlapping of the electron cloud on the p (or π) orbital of the substituent and the electron cloud on the p orbital of the carbon atom of the benzene ring, which causes the delocalization of the p (or π) electrons in a large range. The result of delocalization is that the transfer of the p electrons of the substituent to the benzene ring occurs the conjugation effect of electron giving. If the π electron on the benzene ring is transferred to the substituent, the electron-absorbing conjugation effect occurs.
Most substituents can induce and conjugate the benzene ring, and the final performance is the result of the synthesis of the two.
The direction of induced effect of most substituents is consistent with that of conjugation effect, but the direction of induced effect of some atoms or groups is not consistent with that of conjugation effect.
Methoxy group is p-π conjugated group is electron donor group, conjugation effect is stronger than induction effect.