# Meso Compound-Focus on Missile Compounds

Hi, Course crackers. In this lesson, we’re going to focus on the Meso compound. And then develop an effective way to be able to identify them on testers in exams.

## What is Meso compound

So if you’re ready, let’s get cracking. The easiest way to remember recognize and identify what is Meso Compound is, is by looking at Meso Compound structure. Notice right over here, this carbon Center is a Cairo center. It’s a Cairo or stereocenter because Meso Compound has four distinct groups around there, one, two, and then going towards the top right is different from going towards the bottom.

Notice over here, we’re going to touch bromine faster than going towards the bottom, Meso Compound only going to touch carbon. So we know that’s a stereocenter. One of the criteria of the Meso Compound is to have stereocenters. So I’m just going to erase this for more clarity. On the other side in this carbon, of course, there’s also a stereocenter for the exact same reason.

###### That’s criteria number one

And then the second criteria for Meso Compound is being able to identify a plane of symmetry. So a Meso Compound structure overall is considered an A Cairo structure. It’s Cairo because Meso Compound has a plane of symmetry. So let’s go ahead and summarize the definition of what a miso compound is. Here are the two criteria that have to be met in order for a compound to be considered me.

So number one is Meso Compound has to have stereocenters. Notice in this diagram right over here, here are two stereocenters. And then number two, Meso Compound has to have a plane of symmetry. So you have to be able to identify this plane of symmetry. If these two criteria are satisfied, and you know that you have a measle at hand. Remember that the Meso overall, even though it has stereocenters, remember, has stereocenter.

### What a musical compound Structure

Overall, this structure is still considered Cairo because of this internal plane of symmetry. So now that we know the definition and the criteria, for what a musical compound is, let’s go ahead and practice some of these structures. So notice right over here, criterion number one, does this have stereocenters. Notice that there’s this theory center here, and another Cairo center right over here. So that’s criterion number one. criterion number two, does it have an internal plane of symmetry. So if I try to draw this plane of symmetry right over here, notice that the left-hand side is not equal to the right-hand side, because, on the right, Meso Compound is hydrogen that’s pointing out at you.

Whereas on the left, it’s the bromine that’s pointing out at you, the hydrogen is actually pointing towards the back like this. So we know that it cannot satisfy criteria number two, so no, this is not me. Let’s take a look at this middle structure right over here. So number one does it have stereocenters, in this case, Meso Compound only has one stereocenter.

Notice this is a stereocenter because there are four distinct groups, the methyl group, and h2, the Oh, the hydrogen. Now with only one Cairo center, no matter how I tried to split this, notice right over here, the top side is different from the bottom side. If I take that back, okay, and I try to cut Meso Compound in the middle like this, notice that my left-hand side is not equal to my right-hand side. So no matter how you slice this plane in any direction, you cannot have a plane of symmetry.

#### What about criteria number two

So again, we violate Rule number two. Okay, criteria number two, so this is not a missile. Notice this third one right over here, this third structure, number one, are their stereocenter.

So notice there’s a stereocenter here, because there are four distinct groups, chlorine, hydrogen, and then the methyl group and the ethyl group are different, okay.

Now, on this site, right over here, this is also a stereocenter, as well, because there are four distinct groups, there’s hydrogen that they just haven’t drawn in. So hydrogen always and then methyl group, and then this large group right over here. So there are two stereocenters there for satisfying criteria number one, but what about criteria number two? Is there a plane of symmetry? Well, if I take this structure right over here, and I rotate Meso Compound, okay, even if I rotate it, notice that when I rotate it, I can make the oil Ah, so here’s our CL, notice how the O H is pointing in, I can make it rotate and point out at you like this.

###### How if you try to cut this plane down the middle

But notice how if you try to cut this plane down the middle, notice how the left-hand side would never be equal to the right-hand side because the chlorine and do are different. No matter how you slice this plane, there will never be a plane of symmetry in the structure. So no, Meso Compound does not have a plane of symmetry. And no, this is not a musical structure. So hopefully, after going through those three examples, it’s now a little bit more clear the criteria as to being a musical compound. Now, let’s practice on this right over here. Notice this example when we take a look at this structure are their stereocenter so the answer is yes. Right.

##### Importance of stereocenter

So this is a stereocenter because We have four distinct groups, we have bromine, we have hydrogen, and then going towards the side, this is a methyl group. Whereas going towards the side, notice it’s a different group. Meso Compound a larger structure.

So we know we have a stereocenter, I’m just going to erase these things so that it’s a little bit more clearer. So there’s a stereocenter. Here, for the same reason, there’s a stereocenter. Right there. So that’s criterion number one, there are stereocenter satisfying criteria one.

Number two is, is there a plane of symmetry, so we’re looking for a plane of symmetry in this structure? Well, this one’s pretty straightforward and easy to identify, because if we look straight down the middle, notice right over here, there’s a perfect plane of symmetry. As soon as we satisfy those two criteria, we know this structure is a Meso compound. Here’s another example. Let’s go through our criteria. Again, number one is their stereocenter. So you take a careful look right over here, this Karpen, notice that has four distinct groups.

I’m just going to draw on the hydrogen right here, for us, it’s easier to identify the four groups are as follows, here’s the hydrogen, the chlorine is two, and then going towards your left-hand side, notice your touching carbon was going towards your right-hand side, you’re going to be able to touch this chlorine faster.

###### So we know that these two are different.

So there’s a stereocenter, right over here, let me just go ahead and erase this, so that it’s a little bit more clear. With the same reasoning, you can see that there’s also a stereocenter, right over here. Now, if you just take a look at this, and you cut Meso Compound straight down the middle, you’ll see that the left-hand side and the right-hand side are not the same. Meso Compound-Source-Google|By-Study.com
###### Draw a plane of symmetry

However, if you go and you draw a plane of symmetry right over here, for some of you, you would have already seen this plane of symmetry right over here. But if you don’t see Meso Compound, no big deal, what I’m going to do is I’m going to rotate this structure. When I rotate this structure, let’s call this carbon one, two, and three. When we rotate that structure, notice that carbon number one is now on the side. So one, two, and three.

So here’s the chlorine on carbon number one, it’s still here. Here’s the chlorine on carbon number three. Okay. So in this view, you could clearly see that down the middle, there’s a clear plane of symmetry. So this structure right over here satisfies both criteria. Meso Compound has stereocenters. These two right over here, and a plane of symmetry.

So overall, we would say that this is a musical compound. Here’s another example. Let’s go through the criteria together. So criteria number one are their stereocenters. Notice this carbon right here has four distinct groups, one, two, and then the methyl group is three, and then this large portion is four.

We know this has a stereocenter. So I’m just going to mark this in blue with this asterisk right over here, this is a stereocenter. On the other carbon, we know Meso Compound also a stereocenter. Because there’s one, hydrogen to ch three, three, and then this portion is the fourth one. So these are two stereocenters. Right there. Currently, right now what we have, if we draw a plane of symmetry, we try to draw a plane of symmetry, we’ll notice that the left side is not equal to the right side.

###### However, remember that this is a single bond, right?

This is a sigma bond, it’s a single bond, what I’m going to do is, I’m going to hold everything in the back the same, so hold this side, this side right over here, all of these four atoms don’t move Meso Compound. But in the front, what we’re going to do is we’re going to rotate this Okay, so we’re gonna rotate this down. So let’s see what we get.

First, draw everything on the left-hand side and keep them exactly the same. So on the left-hand side, notice this is the wage rate over here, we have hydrogen in the dashed line, Meso Compound pointing away, and then the CH three right here. And then on the other side, this carbon, we said, we’re gonna rotate.

So when we rotate, notice this group, CH three used to be on top, but as you’re rotating, Meso Compound going to come down to the bottom. I’m just going to draw that ch three using a different color. So we can see. So here’s thatch three, this methyl group that comes down.

###### Conclusion

Now when we rotate Meso Compound two groups right over here, the hydrogen and the wage, as this bond is rotating, they’re both going to come towards the top right here. But not only that, when they come towards the top, this hydrogen used to be pointing out at us, but Meso Compound going to be pointing into the plane of this page. So remember that, let’s go ahead and draw those two. So right over here, here’s a dashed line. And here’s a watch line right over here.

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