Basicity of amine vs. imime (TBR-related)

[Bru]

Just completed passage V chapter 1 and was doing fine until question #33.

I was taught to do acid base by looked at charged species (protonated in this case) and note stabilizing effects. In the case of the imine, I can do resonance which to me would indicate a more stable product so it would be more basic as compared to the amine which lacks resonance stabilization in its protonated form.

What am I missing here? The passage has info regarding hybridization as a means of increasing basicity which is new to me.

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[asf503]

I'm sorry my last post was totally wrong.

You're saying that the N on the imine becomes protonated and the electrons in the double bond attaching it to the carbon moves up onto the nitrogen as the oxygen donates its electrons to form a carbonyl, right? If this is the case, it would result in essentially an amide once water extract's oxygen's proton. This is simply a tautomerization, as the oxygen holding that extra hydrogen is pretty acidic and will gladly donate that H to a nearby water molecule. This means that the imine itself would not be a good base as (in this hypothetical situation) you simply tautomerize the molecule and produce the H back into the solution.

An amine wouldn't have this problem, so an amine would be a better base than an imine.

That's a better answer than my last post, but I still don't think it's the best one. Maybe someone smarter than me will step in.