IR Spect:Drawing Spectra

So now that we understand the frequencies of absorption a lot better, it's time to move on to the second part of what it means to really understand and absorption, which is the shape. Remember that We need to know. Is it gonna be broad? Is it going to be sharp? So in this course, you may be asked to actually hand draw an IR spectrum from scratch. At the very least, if you're professor doesn't ask you to do that, they're gonna want you to be able to recognize what the peaks look like on an IR spectrum and be able to understand the different shapes and identify what they are. So we're going to do in this next section is I'm just gonna walk you through drawing every single important peak that you need to know, and that's gonna help you to familiarize yourself with shapes that are important. So let's start off with the you know, the basic molecules, which is just hydrocarbons. Okay, so we're going to start off with Al Canes, which is just our number one go to simplest molecule to draw, and I'm gonna ask us to forgive my drawing here. These were not meant to be perfect representations, but they should give you a pretty good idea of what we're looking for. So we said that in a normal out cane, how many different types of bonds are there? Well, there's two. There's a C C bond and there's an S P three C h bond. How many of these do we actually draw? Just the second one. We're on Lee going to draw the SP three ch. Okay, so just so you guys know SP three ch. We know one thing about them. They results around 2900. But what is their shape? Their shape is called choppy. Okay, Now notice that this doesn't follow the normal criteria of first word. Second word. I'm not saying sharp. I'm not saying broad. I'm just saying choppy. The reason is because typically, there's so many of these signals of these absorption in a molecule, because think about it. There's hydrogen everywhere, right? They're all gonna overlap with each other and make kind of like a clustered mess around 2900. So instead of giving it a specific shape, we just call it choppy. Now you're wondering what is this gonna look like. So let's go ahead and start drawing, okay? You might wanna watch me do this one first and then just pause the video and copy it down. So what I'm gonna do is I'm really just gonna neglect a Z. You can see this graph starts. My 1500 starts here, so I'm never going to draw anything significant below there. I'm just gonna draw, like a line. I'm literally just like, making this part up. And I'm not gonna do anything until I get to right below 3000. So this is my 3000 marks. So right before there, I'm going to start to draw something, and what I'm going to draw is a choppy peak. Now, when I get to 3000, I abruptly stopped and I continue. Okay. Now notice what I just did there. It's got, like, a few little edges. It's kind of slanted. That's gonna totally change based on the exact ir spectrum. Um, but in general, that's what we're looking for. We're looking for something that's a little bit more than halfway down. Um, in terms of transmit INTs on bits, something that has a like a jagged edge. Okay, you're gonna see me draw these Ah, lot during the course. Okay, so that was easy. Let's move on to our second situation, which is Al Keynes. Now, notice that Al Keynes had mawr that we had to worry about because we still have that Sisi, which we're not going to draw. But now we had two different piece that we have to draw. We had the C double bond C, which is here and here. And we also have the SP two c h. Okay, so that's in addition to the rest of the hydrocarbon that still has s P three ch. So what I'm trying to say here is that we've got these two extra peaks that we have to worry about that are complicating this more than just a regular al cane. So how do we draw this? Well, these we're all gonna have their own peaks. They need to know. So 1600. I'm sorry. I just gave it away. I'm on automatic mode right now, So we just talked about how a c d 01 c would result in the double bond region. That's gonna be 1600. And what is that gonna look like? Well, that is gonna be week and sharp. Okay, so the peak at 1600 is expected to be weak and sharp. Then we would expect both of these to be choppy. Okay. And we know there ranges. We talked about how sp three is 2900, and we also discussed Tell SP two is 3100. So, basically, we're gonna have ah, lot of choppiness everywhere from between 29 30. 100 this time. What's going to be very distinct about this graph is that it's gonna go past 3000, and it's going to continue to be choppy after the 3000 points. So once again, probably better for you to just let me draw this and then you can copy it down. So we're going to do here is once again blah, blah, blah. No one cares about 1500. But wait. This time, when I crossed 1500 I immediately have to draw a week sharp peak that's going to represent my C seeds. Will bond. This is my CC double bond. Okay, so it's my week sharp peak. Now, once again, nothing really happens for a while. I'm bored, but I get to 2900 and I have to start paying attention. Because now what I'm gonna have is I'm gonna use the different colors. I'm gonna use red for the Al Cane blue for the Al Keen. I'm gonna have my choppy peak once again. And usually, if this was just in Al Kane, I would stop right here. And that would be it. Don't draw this now because there's and Al Keen component there's these sp two hydrogen. That means that some of this choppiness is going to continue past past the 3000 mark. Okay, so the chop, the little spikes that happened after 3000 offer the SP two component and the spikes before our for the S P three component Does that make sense? So suddenly? This graph just got a little bit more complicated than the one that we drew before. Cool. So far. Awesome. So now let's move on to terminal al kinds. Now, remember that I stated earlier that it's very important that you Onley use terminal all kinds here because you must have ah, hydrogen on it to get that s p peek. Okay, so let's look at this molecule. This would be a typical al kind that you might have to draw and looks, like identify once again. Like we've always done all the different bonds here. Well, we've got once again Sisi. Who cares? I've also got my S P three C h. By the way. Heads up. You're always gonna be drawing. That s P three C h. Okay. Get used to it. He's around to stay. Because remember that Al canes are the backbone of all organic molecules. So what are the chances that there's no Al cane component? Very little. You're almost always going to draw a ness P three ch um, absorption. Okay, so we were Xing out. This one, this one we're definitely gonna draw. But what else do we have? Well, now we have a C triple bond. See that we're adding. And we've also got an S P C H bond, which is the hydrogen. That's right here. Okay, so this just got interesting. We know that the peak at, um at the SP three is going to be 2900. We know it's gonna be choppy, but what do these other guys look like? Well, cc triple bond, if you had to guess where it's gonna be. Triple bond region. That's going to be 2200. And once again, similar to our al Keen. It's gonna be weak and sharp. Okay, It might be medium. It's somewhere between weak and medium. Okay, it really depends on the drawing, but for the purposes of memorizing, I'm totally fine with you drawing it just like you would draw on all keen. Okay? Because it really depends on the exact spectrum. So 2200 week sharp. And then we've got the S P C h. Okay, which, because of what I told you guys about hybridization and the wave numbers, this one's actually gonna result the highest at 3300 centimeters. Um, and this one's actually going to be strong and sharp. Okay, So you might be wondering, um, Johnny for hey, why is this hydrocarbon? Why is this age showing up a sharp when all the other ages that I've been drawing have been choppy? OK, and the answer actually lies in the drawing. Notice that the drawing I only have one. There's only one h. So why would it be choppy? Okay, there's only one absorption is gonna happen. It's from that exact hydrogen, so that can't be choppy. It's gonna be just one lone sharp peak of 3300. Okay, so let's go ahead and give this a world I'm going to start off. I completely ignore 1500. By the way, just so you know, I've been ignoring it. But it might as well look like this, you know, there might be stuff going on, but the whole point is that I don't care. Okay, so it could have spikes. It could not have spikes. Doesn't really matter. Point is that nothing's gonna really happen until I get to 2200. When I get to 2200, I'll give my week Sharp peak. Okay, so that is going to represent my see triple bond. See, in the triple bond region from there, I'm gonna go ahead and draw my Al cane my C each That is S p three hybridized. As you can see, I pretty much always draw these peaks the same. They're kind of choppy. They're kind of regular looking now, in this case, because there's kind of a gap between 2900 and 3300. They're not going to be back to back. So I actually would expect this to kind of descend all the way back down. But then I'm gonna have my sharp, strong and sharp peak coming from my al kind. Okay, so this is my SP three ch. That's choppy. But now this is my strong and sharp SP hydrogen peak. Okay, so notice that there's actually a separation here. Okay? Now, what might get even more confusing is if you had a molecule that not only had a triple bond in it, but let's say it also had a double bond in it. Right. So you had a ches there, then what would happen? Well, then, that just means that anything that's SP two would wind up going in here. This would be your SP two range. So in that case, there might be a little bit less separation. Okay, But we've definitely gone over pretty much all the possibilities that can happen just with these straight hydrocarbon chains. Okay, so I hope that's making sense so far, we have to solve a lot of functional groups to go. But this is your basis. This is your kind of your fundamental groups and Now we're going to start learning new functional groups that you're gonna add to this. Okay, so let's move on to the next video.

So now we're gonna move on to drawing and recognizing functional groups with hydrogen in them. And these were gonna be alcohols and amines. Okay, so the first we want to focus on is really the granddaddy of all absorption, and that's alcohol. Okay, So alcohol's a Z said are one of the broadest absorption that there is, and they absorb from 3200 all the way to 3600 in their absorption. So this thing is massive. Remember that I told you that alcohol almost looks like a parabola. Okay, that o h is gonna look huge. The official name for this type of, um, absorption is that it's strong and broad. Okay, so that should tell you strong. It's moving all the way down to the floor and broad. It's very, very wide. Okay, now, on top of that, because of the fact that I'm always including an alky in component, what other peaks should we always be drawing? We should always be drawing R S P three c h bonds as well, because all of these molecules are gonna have those. Okay, but notice that I have C C single bonds, which I'm excluding. I also have C o single bond, which I'm excluding as well, so I don't worry about anything else. I'm just gonna draw those two absorption, so let's go ahead. I've got my fingerprint. Who cares? Now I move all the way to 2900, and once again, I'm going to draw my SP three. At this point, you guys should be pretty good at drawing these sp three go crazy. You know, I expect different shapes coming up at this point. Okay, You got your choppy sp three Peaks. But what's gonna happen? Well, when we get to 3200, it gets riel. This alcohol is gonna be huge, is gonna do something like this. Boom. Okay, now, in this, um, Spectrum, I actually went past 3600, so I probably drew it a little bit too big, but it's not a big deal. The whole point is that I just want you to know that it's a huge, massive peak that takes a pretty much the entire 3000 area, and that can actually make it kind of challenging because alcohols are so large in terms of their absorption that they tend to block out things that are behind them. So remember that I told you, for example, what's an absorption that you can think of that happens between 3200 and 3600? Remember, our triple bonds are 3300, al kind. So imagine that you have an alcohol, but also a terminal al kind that has a sharp pekar on 3300. You might barely see it. In fact, what it might look like is you might have a alcohol that looks like this. It's coming down, and then it has this sharp little thing, and then it keeps going, okay, because you could almost think of an iron spectrum as a silhouette. It's almost like a shadow of all the peaks, so you can't see multiple layers or multiple dependent dimensions here. If there truly waas a SP hybridized ch along with an alcohol, you might only see a little peek like that popping out, just popping right out of the alcohol peak. So what? My whole point here is that alcohol's can make reading the 3000 region a little bit challenging because they take up so much space and there's really nothing we can do about it. okay. One of the limitations of IR spectroscopy. Now let's move on to a means. And what you'll notice is that I've got primary means and secondary means, and they're going to result differently. Let's start off with primary means and then move on to secondaries. Okay, Then I'll explain why Tertiary zehr Not on this page. Well, the general rule for means is that you're going to draw as many peaks. Same number of absorption as hydrogen is that you have in your mean So a primary mean has how Maney hydrogen two. Okay, so that means that we would expect it tohave two absorption zones. Okay. And in general, thes absorption are gonna be weaker and sharper, then alcohol. Okay, so if you guys recall, the range of a means was somewhere between 3300 and 3500. So that means that a means could completely get covered by an alcohol if it was present. Now, thankfully, your class is not going to go into that much complexity where you have to, like, figure out what's behind the alcohol, but just letting you know that there's a lot of overlap between these ranges and really the only way that you could tell The difference is by the shape because it's weaker and it's sharper. Okay, now you might be wondering, you know, why does it have these two different absorption? And I'm just gonna tell you quickly, this is beyond the scope of the course. You don't necessarily need to know this, but basically, there's two types of there's two types of vibrations that are gonna be happening with your mean Okay, when we talked about how there's, like stretching, wagging, rocking and all of those air under the umbrella of vibrations. Well, when you have those two hydrogen is present on the mean, you're gonna have a type of vibration called symmetrical stretching, and you're gonna have a type of vibration called asymmetrical stretching. Okay, I'll tell you what, I'm going with this in a second symmetrical looks like this that both of them are stretching exactly the same. Okay, asymmetrical is where one is stretching in a different direction than the other. Okay, because you have these two different vibrations that are kind of vibrating at different frequencies, one is going to be higher than the other. The symmetrical stretch is gonna be right around 30. 300. Okay. The asymmetrical stretch is gonna be a little higher. It's gonna be around 3400. So that's why when you have two, hydrogen is present on the mean, we're gonna expect double peaks. Okay, so that's enough for now. Let's go ahead and draw, and then I'll explain why this is important. So we're gonna go ahead and do nothing. Nothing, Nothing. Nothing. We get to 2900 and we draw our choppy SP three So much fun. And then we get to around 3300, and this is where we draw our mean peaks. So we're going to get, uh, you know, a week weaker, Sharper peak around 3300, and then another peek around 3400. And that's so ugly. I'm just gonna do it again. I'm sorry that Z looks like slime or something. So let's just do try this one more time, okay? That's a lot more like what I was trying to draw. Okay, so you've got this double peak where, um, the lower peak at the 3300 has to do with the symmetrical stretching, and the higher peak is with the asymmetrical stretching. Does that make sense? So far? Awesome. Okay, now note that another bond that we didn't discuss was R C single Bond n Bond. But recall that that would just go in your fingerprint so we don't have to draw it. Excellent. Okay, So now why is this symmetrical and asymmetrical thing important? Well, because look at secondary means. Secondary means Onley have one hydrogen. Okay, so that means that when this thing is stretching, its Onley gonna have one type of stretch possible, which is symmetrical. Okay, because there's no asymmetry here. There's no possibility of hydrogen is going in different directions. So since it only has one age, we expected to just have one absorption. Okay, Now, what I haven't told you is what's gonna be the range of that absorption? Because it's symmetrical. Would you expect it to be lower around 3300 or higher around 30. 400? What do you think? Take a stab at it. You can use the above notes. Yeah, guys, it's gonna be a 33 100 Okay? Because there's no reason for it. Thio be boosted to that higher frequency. Right? So hopefully that difference is making sense. one hydrogen, one type of stretch, One signal. So we're just gonna go ahead and draw this again? We've got our SP three over here, and then when we get to 3300, we just have one loan, you know, week sharp peak around 3300. Okay, as you can tell thes peaks, no matter what type of a man you have, they look far different from alcohol. And they should never be confused with alcohol. In fact, if you confused anything with alcohol, I'm gonna be personally disappointed in you. Because alcohol is probably the most easy to recognize Absorption there is. Okay, you can't really confuse anything with it. So let me know if you have any questions. Oh, wait. One more thing. Can't. Don't leave yet. So we did primary mean we did secondary. I mean, why is tertiary me not on this chart? Why did I just run out of room? Is that the next thing we're gonna talk about? Not necessarily. It's because notice that a tertiary mean if I were just to draw it down here. Tertiary Amine, how many hydrogen is? Does it have no hydrogen? Okay. Tertiary amine by definition, is that you have an end with Onley are groups around it. Okay, so are you gonna see and the mean peak with a tertiary mean? No, you're not. So this is actually in a mean that would not result in the functional group region because we don't even have a hydrogen present. So that's why you're only going to see your double peaks for primary. And you're single peaks for secondary and you're going to see zero peaks for tertiary. All right, so that's it for this topic. Let's move on.

So now we're gonna throw some Carbonell Bonds into the mix, and we're going to start off with the easiest scenario, which is just learning how to draw simple carbon eels. Okay, so now recall that my definition of a simple Carbonell was just a carbon Neil. That's Onley in a result in one absorption. Okay, it's a carbon. You'll that you only have to worry about one time. It doesn't come back to haunt you a second time, okay? And we're not gonna cover all of them here. But, you know, we've got two good examples. We're gonna cover key tones and esters, and I'm gonna explain why they're simple carbon eels. Well, we already know that we should be getting used to the peaks there being R S P three c h bonds. Right. But we know that we have a C double bond. Okay, so now remember that see, double bond owes are always going to result in the carbon you'll region, and there are specific ranges that relate to different functional groups within that region. Key tone would count as my are of corn of the acronym corn. Right. So that means that hopefully guys remember these ranges that this is going to result at 17. 10. Okay, Now, carbon eels are probably the second most distinctive. Are easy to recognize absorption in ir spec because they're extremely strong and sharp. And that's gonna apply toe all carbon eels, not just key tones, not just the are. That's gonna rightto every single letter of corn. They're always going to be strong and sharp, meaning that I wanted to almost hit the bottom of the spectrum, and I want it to be very, very sharp. Okay, so let's go ahead and draw this guy. I'm gonna do nothing up until 1500 now, right? When I get to 1700 I'm just gonna go for it. I'm gonna draw the sharpest thing I can imagine. It goes almost all the way to the bottom, and I try to make it a sharp is possible. Okay, then I go ahead and I do nothing until I get to 2900 and I complete my chops. Okay. Now, this is just it's getting uglier and uglier, but it doesn't really matter, because that's not the point. The point is that we have this new peak at 17. 10 Okay, so there's no other bonds here that I have to worry about. So that's really it. That's gonna be the full spectrum for a key tone. Now, notice that there isn't a second type of bond have to worry about there's no bonds, hydrogen extra bonds or anything like that. So we're done. Okay, So now what's going to be the different? The biggest difference between drawing a key tone and drawing. And Esther? Well, let's look at the different types of bonds. We haven't, Esther. Once again, we have our s P three ch. So we're also we're always gonna draw that now. We also have a carbon, Neil. Now, this Carbonell happens to be an Esther, which is the O in corn. So that means, would you expect it to be higher than 17 10 or lower? Hire these results of the those results at 17. 50 around 17. 50. Okay, so I'm gonna expect 17. 50 now. Has anything changed in the shape? Is it gonna be like a different looking carbon eel that I'm I'm just like, Oh, this is definitely an Esther Because of how it looks. Guys know every single carbon you'll looks pretty much identical. It's always gonna be strong in sharp. Okay, so that part really hasn't changed. Actually, this looks exactly the same as the one we just drew, except it's up by four wave numbers. Okay, Now, if you look at the units that I have on this X axis 40 is almost an imperceptible difference with how low without big I have these units, meaning that I could probably copy and paste the exact spectrum that I drew at the top. And it would apply to this one because there's gonna look identical. Okay, But we do have this extra bond. Notice that in an Esther, you have a si o bond that's created. Where does see results? See Single bond? Oh, guys, this is fingerprint meaning that in Esther is a simple carbon, Neil, it's not going to create a second bond. You have to worry about you don't even draw this. Meaning that the whole point of this exercise is that I want us to know that Esther's and key tones pretty much look exactly the same. We're gonna do this. Then instead of waiting till 17. 10 I'm gonna wait till 17. 50. But as you can see. I mean, that is hard to draw. That is hard to figure out. Okay. And then finally, I have my SP three blah, blah. I drew in both ugly. Perfect. So notice that if I look at this one back to back with this one, the key tone in the Esther are almost impossible to differentiate. The biggest difference is that if a problem that your professor gave you said 17. 50 if it actually stated the number right here, then you would know. Oh, this is an Esther. Or if it stated 17 10 then you think, Oh, this is an Alka Haider. Kids don't get what I'm saying. So the numbers are really important here when it comes to these little tiny differences in wave number A more specific numbers probably necessary for you to be able to tell the difference. Okay, so now you guys understand what a simple carbon eel is. Let's move on to more complicated systems. So we're done with this topic. Let's move on.

So now that we know how to draw simple carbon meals, we have to take the next logical step and move on to complex carbon eels. So complex carbon eels remember, Are those carbon deals that have to absorption zones? Okay, So complex carbon eels are gonna be those molecules that you wanted kicking yourself about later, after the exam, because you drew the first absorption and you forgot to draw the second, okay? Or maybe you didn't know what the second absorption was about. So that's what we're gonna go over now, because these are a little bit more complicated. Okay, So Aldo hides are great example of a complex Carbonell, because once again, we've always got r S P three ch, which you know we'll have that taken care of. We have a C o double bond, which, in this case, it's an alga hide. So where would I expect that to result? You know, you got this. That's the are in corn. Aldo hides in key tones. That's gonna be 17 about 17. 10 again. Okay? And we know the shape doesn't change strong and sharp, But notice that now we also have this other bond. They have to worry about just a second. So we have this other bond they have to worry about, which is C H. But it's specifically an alga hide ch specifically alga hide. And this one's tricky. This one is its own set of peaks that we need to know and actually turns out that alga hides the ch happens to have a double peak. Okay, so we're gonna see is double peak or double absorption? Okay, at and 2800. Okay. So, usually I mean when I told you earlier just said 27 because that's where it's gonna be centered around. But typically this shows up as a double absorption. Okay, now, sometimes that 2800 peak is going to kind of blend into the 2900 peak that you get from Al Keynes. Right? So sometimes the rial Onley thing that you're going to see is this 2700. Okay, because the 28 is kind of close to the 29. But the biggest point here is that if you see something at 2700, that's very distinctly in Alba hide absorption. There's nothing else that results in that range with that type of peak. So let's go ahead and draw this. Um, we get to 17. 10 and we draw are very aggressive absorption. That's our carbon yells That's gonna be our Cedo and then we get over to our alto hide are all die. It's gonna look like a double Pekar on 2700. So I'm gonna draw that like this. I'm gonna draw that like a peek here and a peak here. But notice that the second one is kind of going to kind of blend in to the choppiness that happens around 3000. Okay, so notice that I mean, in this case, I did a pretty good job of conveying my point, which is that sometimes all you're going to see is the 2700 that comes from the Alba hide ch. Okay. And it's important that you recognize that sometimes you're going to see a double peak there. But sometimes you might just see that one peak, because it kind of blends in. Okay, But technically, both of those peaks came due to Is the alga high OK, and then finally we have all of our s P three c h over here. Cool makes them so far, so complex. Carbon deal. There's a little bit more than we have to worry about. Okay, Now let's move on to carve oxalic acid car. Oxalic acid is also a complex carbon deal. So we've got our S p three c h. Kane. We've got our c double bond. Oh, that in this case would result where I heard you say it. 17. 50. It's the Owen corn. Good. 17. 50. Um, but then we've also got this other peak. We have to worry about the O. H. Now what did I get? What did I tell you guys about O. H bonds? Previously? I told you that these air very broad peaks that will be around 323,600. Okay, but be very careful not to call this an alcohol, because it's not. This is not an alcohol. This is a carb oxalic acid. The O. H. Is going to change its properties when it's next to carbon Neil. So this oh, age is actually gonna have a very different range. It's actually gonna have a very it's. First of all, it's gonna be strong, and it's gonna be very broad. In fact, I'm even gonna put the word here very because this is the most broad peak that there is. Okay. And it's going to start around 2500, And sometimes it ends around 3000, which can happen. Sometimes it can even go all the way up to about 3300. Okay, so this thing is a mess. It kind of imagine that it's like you took the alcohol peak and you just shifted it down and stretch it out. Unless you're gonna get now, think about it. Do you know any other peaks that results between 253,300? Almost everything. A ton of stuff results there. So you can imagine that this absorption is gonna block the view of a lot of these other peaks. Okay, so we're gonna think about that number. This is supposed to be drawn like a silhouette. So I'm gonna be drawing my car broke cilic acid, and there's other gonna There's gonna be some other stuff sticking out of it. So let's go ahead and start off. I go to 17. 50 and I draw my carbon Neil Spike. Okay, then when I get to 2500, I start drawing this really incredibly broad peak. That kind of looks like this. Okay, so it's kind of just start off. It's not quite as deep as strong as an alcohol, but it definitely is broad. So we got this thing going on, but it's not gonna end here. Remember that I have these 2900 peaks to draw, right? So I'm gonna draw that kind of sticking out. It's gonna be kind of like this, and then it's gonna come back, and then I'm gonna finish off with the end like that. Okay, So what you wind up getting is kind of like a overlap of peaks that is very common with carbo oxalic acid. And sometimes it clouds the view of your choppier al canes and al canes and stuff like that, which makes it kind of problematic. Okay, so that would be another example of a complex Carbonell since I had to worry about my seagull 10 but I also had toe worry about specifically the O. H that was involved in the carbon eel. And then once again, I always had the SP three CHS before. Okay, So now you guys got it. You got simple and you got complex carbon deals. So let's move on to the next topic.

This is just a quick little video to address a subset of functional groups that you might not usually think of as related. And these functional groups are all gonna be what we call concealed functional groups because they don't show up. And I are. So let's go ahead and talk about thes and why exactly that happens on what they look like. So these groups are as follows. We've got alcohol slides, ethers and tertiary amines thes groups. Even though they really seem like they have nothing to do with each other, they actually have something really big in common, which is that you're not going to see these in the functional group region. Okay, they have no absorption zones in the functional group region. Okay, why is that? Well, because remember that in orderto have a absorption in the functional group region, you need basically three different things. One of three things. You either need a double bond or you need I'm just gonna put numbers here, So you need one a double bond to or you need a triple bond three, or you need some kind of bond toe hydrogen. Okay. Well, it's okay. So now we look at these three on what we wonder is, Well, what kind of bonds do they have? What we're going to notice is that they all have s P three c h bonds. Okay, so all of them have that you really pretty much every single molecule in the world is gonna have that. Okay, But then, besides that, what else do they have? Well, this one has C x, this one a c o. This one has CNN. What's kind of the common theme here? None of these extra bonds are going to result because these air all fingerprint bonds, these air all bonds that would show up below 1500. So that means that when I draw the I r for these molecules, what are they gonna look like on IR? Thes molecules are all gonna look like al canes. Okay, because the Onley bond that they have to age happens to be the out Cain. Not anything else. Nothing else has a bond to H. The only thing that the only reason I'm going to see these things at all, there's gonna be any absorption has to do with the H is over here. It doesn't have to do with the functional group at all. Okay, so that means that these three functional groups are going to be in perceivable from Al Keynes. So you're gonna need to use other clues to figure out if you have them. Okay, let's just go ahead and draw this really quick. So that means that I would expect that the spectra for these guys is literally gonna look just like an Al cane. And that's it. Nothing else. It might as well it could have been. Well, let's don't wanna do that. It could have been cyclo butane or something. You know, it could have just been a NALC cane. Um, but it happens to be, you know, it happens to be an alcohol. Hey, lied. Or it happens to be in either. You're never gonna tell on IR. Okay, so it's another limitation of ir that ir doesn't do a great job of picking out these different functional groups that don't show up in the functional group region. Okay, Um, now I mean a quick note that some professors might say Oh, that you can use the fingerprint region Thio tell if you have these molecules or not, and The truth is, it's complicated. The truth is, is not a straightforward as they might say, and most courses in organic chemistry. One and two are not gonna cover that. So that's why, like I said, I'm ignoring the fingerprint region. But for right now, we're just going to assume that you can't see these functional groups on an IR spectrum. Alright, so hope that made sense. Guys, let me know if you have any questions. Let's move on to the next topic.