Why is NH2 a strong activator?

Electronegativity of oxygen is more than that of nitrogen. Thus NH2 can donate its lone pair more easily than oh group whereas OH group has more electron pair pulling tendency. Hence nh2 shows a stronger +R effect than oh 🙂 OH and NH2 have different modes of donation and withdrawal.

Is NR2 withdrawing or donating?

A group with a positive mesomeric effect (+M) is an electron-donating group that ‘pushes’ electrons onto the carbon atom it is bonded to, usually via a lone pair that can make a resonance structure. This increases electron density on carbon and beyond. Amino group (-NH2) and alkyl analogues (-NR2)

Which is more activating OCH3 or NH2?

-NH2 will give more electron density than it takes, and thus -NH2 is an electron donating group.

Is NH2 a activating group?

Common activating groups (not a complete list): Alkyl, NH2, NR2, OH, OCH3, SR. Common deactivating groups (not a complete list): NO2, CF3, CN, halogens, COOH, SO3H. If you think about it, you’ll also see that where you put the group E on the ring will also influence the carbocation.

Why is NH2 stronger base than OH?

Water is neutral whereas ammonia is a weak base (even less acidic). Stronger conjugate acids have weaker conjugate base and vice versa . Therefore, NH2- is a stronger base. OH- is better leaving grp because NH2- is stronger base.

Is NH2 a strong deactivating group?

Nitrogen and oxygens with lone pairs – amines (NH2, NHR, NR2), phenol (OH) and its conjugate base O– are very strong activating groups due to pi-donation (resonance). Atoms with pi-bonds to electronegative groups – Strongly deactivating. NO2, CN, SO3H, CHO, COR, COOH, COOR, CONH2.

Are activating groups electron withdrawing?

Electron donating groups are typically divided into three levels of activating ability (The “extreme” category can be seen as “strong”.) Electron withdrawing groups are assigned to similar groupings. Activating substituents favour electrophilic substitution about the ortho and para positions.

Which is more activating OH or OCH3?

OH (hydroxy) has a better +R effect than OCH3 because The -CH3 group in -OCH3 causes steric repulsions with lone pairs, increasing bond angles. Due to which it make -O- atom of -OCH3 more electro-negative and thus affecting donor tendency.

Which is more electron donating NH2 or CH3?

Nucleophilicity is the tendency of the atom to donate electrons. Negative charge is more stable on more electronegative atom. Among NH2– and CH3– ,nucleophilicity of CH3– is more since negative charge on nitrogen atom is more stable than carbon ,so carbon will be more willing to donate electrons.

Why is NH2 a strong base?

NH2- Acid or Base NH2- is a strong base because it is unstable with its negative charge in a solution so that it wants to take the edge off with a negative charge by accepting a proton and acting as a base. LIST ACID.