So guys, everything on this page was fairly easy and now I just threw in a really hard question at the end. I'm just envisioning a few of you arguing with your friends on the computer saying, no it's this. No it's that. It's really this. And you're like about to punch your friend and then you're like, let's just play the video and see what it is. Well, I'm sorry to tell you that you might both be wrong because this is such a hard problem. I'm going to take myself out of the screens so we can talk about it. Guys, sadly this molecule is actually drumroll aromatic. How in the world is this molecule aromatic? I know that was the last thing you were thinking. How could that be? Okay. Well, let's go through the first step. The first one is that obviously it's cyclic.
2, is it fully conjugated? Well, there's an area here that is missing conjugation. If you'll notice, this carbon here has 2 H's, correct? This carbon is not fully conjugated. That means that in order for my pi conjugation system to exist, it can't exist on this ring because this part of the ring is not fully conjugated. Remember that I told you guys, I'll just bring myself back into the camera really quick. Remember that I told you guys that in order to be fully conjugated, you just need it to be conjugated around the perimeter of the molecule or around one perimeter. You just need to have one loop of pi electrons that make sense. Now typically for the monocyclic or for the polycyclic molecules we've been looking at, we go around both rings. But notice that on this molecule, we've got a problem. This carbon right here is not fully conjugated. There's no way that I can go all the way around. If I go all the way around, I'm going to get stuck here. So that means that this ring can't work which means that my pi conjugated system is actually limited to only this ring. This is the perimeter that I care about. This is the ring that is fully conjugated. What that means is my loop or my loop of conjugation is only around this ring and not around this ring. It is fully conjugated but only with one of the rings. Meaning that 3, is it planar? Sure. 4, how many pi electrons are in that ring? Well since let's say this is ring A and this is ring B, right? The pi electrons in ring B don't count because they're not part of the pi conjugated system. That means I only count the electrons that are in the ring that's actually fully conjugated which would make 2, 4, 6 electrons. This has 6 pi electrons which makes it aromatic. Actually this is similar to a benzene ring just with carbons coming off of it. But it has pretty much the same stability that you would find in a benzene ring. So, I'm sorry to burst your bubble. I know that you were doing great with this page. In fact, you were probably like in snooze mode and all of a sudden, you're painfully woken up and you realize that you could be thrown a question like this on your exam and get it wrong. So I just want to let you guys know that it's not always easy. You have to think. You have to use what's here. Can't turn it off just yet. But if you apply the four rules, you should be fine. Let's move on to the next topic.