# Donation by inductive effect and withdrawal by conjugation

Is there a group that would attached to a benzene ring, donate electrons by inductive effect and withdraw them by conjugation?

• Well, I guess a $\ce{-BH2}$ group attached to benzene ring would have this effect. It has an empty $\ce{p}$ orbital that would withdraw electrons via conjugation, but $\ce{B}$ is less electronegative than $\ce{C}$ and so it would have a positive inductive effect. – Philipp Sep 2 '14 at 19:58
• Thank you for the answer. Now, an additional question: Where would substitution happen on the aromatic ring? – RBW Sep 2 '14 at 20:52
• Usually conjugation beats inductive effects. So substitution should happen in the meta position. – Philipp Sep 2 '14 at 20:57
• How probable is ipso substitution? – RBW Sep 3 '14 at 14:59
• @Marko It's okay to ask a new question for follow-ups. If you want to reference that it's a continuation of this question, you can link to this one. – jonsca Sep 5 '14 at 20:14

I guess a $\ce{-BH2}$ group attached to a benzene ring would have this effect. It has an empty $\ce{p}$ orbital that would withdraw electrons via conjugation, but $\ce{B}$ is less electronegative than $\ce{C}$ and so it would have a positive inductive effect.