The following compound can become protonated on any of the three ...

Question

The following compound can become protonated on any of the three nitrogen atoms. One of these nitrogens is much more basic than the others, however.

a. Draw the important resonance forms of the products of protonation on each of the three nitrogen atoms.

Accepted Answer

Hey everyone, Let's solve this problem. It says the given structure contains three nitrogen atoms having different basic strengths, draw the significant resonance structures of the products formed by the pro nation of each of these nitrogen atoms? So we have a tertiary nitrogen nitrogen number one, nitrogen number two, which is a secondary nitrogen Amin rather and our third nitrogen, which is an amine group. Okay, so we have a tertiary amine secondary, I mean, Amin and an amine nitrogen. Okay, so let's draw out these structures and show what they would look like when they gain a proton. Right, That's what a base is. It can gain a proton where as an acid wants to give away that proton or that hydrogen. Okay, so let's look at the first nitrogen if it gains a proton right there and the rest of the structure is the same. So when that nitrogen gains a proton, it now only has four electrons touching it rather than five. So it's going to have that positive charge. There. Can the structure have any resonance forms? Well, I see a double bond next to a positive charge. But if those electrons were to swing down towards that positive charge, that would violate the octet of that nitrogen. So, this structure actually is not stabilized with other resonance forms oops, resonance forms. So, is this going to be very stable as a cat ion or Very basic? No, so not very stable or basic. Right? Because if it's not stable, it's not going to want to exist in this form. Which means it's unlikely that this reaction will happen. Okay, let's look at Or secondary, I mean, # two. So what does that look like when that nitrogen gains a proton? So we have NH two, here's no long pair now. And similarly destruction. Number one, there are four sigma bonds. So that will have a positive formal charge. And again we see now that positive charge on the other side of the double bond, but it's the same sort of structure as number one and that there are four sigma bonds. So if that double bond came down here to share its electrons and created a double bond between that nitrogen and center carbon that will violate nitrogen octet. So this structure is also not stabilized with resonance. There are no other resonance forms possible. So it will also be not very stable or basic. This is not likely to occur if it's not stable. Let's look at the last structure, number three, C H three bomb into nitrogen Bonded to carbon double bond to now in H2 bond into nitrogen Bond to CH three. So now this nitrogen has 1234 bonds for electrons touching it. So that has the positive charge. Can this compound have resonance forms. Can the structure rather have resonance forms? Yes, so these electrons from the double bond can go towards that positive charge, right, negative charge moving towards that positive charge. So what would that look like then there would be no more double bond between that carbon and nitrogen. And now we would have NH2 and a lone pair. Well, our compound doesn't just become neutral now because we moved electrons. So that positive charge is going to be on the carbon now because we took those electrons that was sharing with nitrogen and moved them to the nitrogen. Okay, are there any other resonance forms? Yeah, there's actually two because we see the lone pair on this nitrogen next to that positive charge and the lone pair on this nitrogen next to that positive sorry, positive charge. So we can show two structures in which the electrons are coming from each side. So first let's show if they go down from that nitrogen on the left we would have ch three nitrogen double bonded to the carbon in H two. Okay, so now the nitrogen would have a positive charge because it gave up some of its electrons to share with that carbon. Right, and similarly on the other side, if we have those that lone pair on that other nitrogen going down towards that carbon, we would get the structure. So now carbon double bonded to N. H. And now that nitrogen will have a positive charge because it shared its lone pair with that carbon. So what do we think about this structure if this nitrogen is protein ated? The third nitrogen, we see that there are three resonance forms. So since this product is stabilized With three resonance forms, do we think it's gonna be basic? Yes, that is definitely preferable for this nitrogen to get protein ated. So this is going to be the most basic form of this structure. I hope this video is helpful, and thanks for watching.

The following compound can become protonated on any of the three nitrogen atoms. One of these nitrogens is much more basic than the others, however. a. Draw the important resonance forms of the products of protonation on each of the three nitrogen atoms.

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The following compound can become protonated on any of the three nitrogen atoms. One of these nitrogens is much more basic than the others, however.
a. Draw the important resonance forms of the products of protonation on each of the three nitrogen atoms.