Hello organic chemistry students. In this video we're going to go over what organic functional groups are. Now this term organic functional group really defines what a molecule is, much like a name does. Like for myself, Professor Rafferty, that's who I am.
If it was Professor Smith, that's a totally different person, totally different life experiences, just like different functional groups are. Now the very first functional group I'd like to go into is something called the hydrocarbon. Now this is the very basic functional group. That's like calling me a human.
Wow, that's very descriptive. You're a human. Wonderful. What does that mean?
Male, female, old, young, no hair, some hair, and stuff like that. So a hydrocarbon is very basic. When we say a hydrocarbon, it basically just means a compound with hydrogen and carbon in it.
Nothing else. It's pretty bare basic. Now there's several types of subtypes of hydrocarbons. The first one is an alkane, which we're going to be learning about, an alkene, an alkyne, and then an arine. Now we're going to explore each of these in this class.
So let's go ahead and talk about what the differences are between them. An alkane, all the carbon-carbon bonds in the alkane are single bonds. meaning that there is no carbon-carbon bonds that are doubly bound together. They're all just held together by one sigma bond, and that's it. In an alkene, there's at least one carbon-carbon double bond.
In an alkyne, there is at least one carbon-carbon triple bond. Now notice here, I'm not saying a carbon-oxygen double bond or triple bonds or anything like that. It's carbon-carbons.
That's the important thing. Hydrocarbons are just... hydrogen and carbon. And an airine is going to be a cyclic six-membered ring with a concept called aromaticity that we're going to be learning a lot more about. Aromaticity, there it is.
So what does that structure look like? I'll go ahead and show it to you right here. We will get into more detail about this later on.
There's an airine ring system. Wonderful. Now, We can also have functionalized hydrocarbons. A functionalized hydrocarbon is going to be a molecule made of carbon and hydrogen, but with other groups on it. So here we can have ones that contain halides, which are the halogens.
We can have ones that contain alcohols, ones that contain esters, and the list goes on and on and on. And this is where we're going to spend a lot of this class, in functionalized hydrocarbons. So just calling something a hydrocarbon is not descriptive enough.
Unless it is purely just made of carbon and hydrogen, nothing else, then that's fine. If there's any other more advanced functional groups, we have to use that functional group name. That's going to be the key characteristic here.
So, actually, next slide. Let's go ahead and go over some of those other functional groups and key ones. The first one I already mentioned is a halide. So a halide is going to be a halogen attached to a carbon. This X right here can be fluorine, chlorine, bromine, or even iodine.
And that's just a halide. Another one is called an alcohol. Now an alcohol is going to have an OH on a carbon. Now very important, this carbon right here must be sp3 hybridized. That is very important.
This right here is ethanol. This is what gets you a little drunk if you're drinking an alcoholic drink. Now, this right here is called a phenol group.
Notice I'm going to put this arine ring system in. Oh, and there's the OH. Now, that seems kind of stupid.
There's an OH here on a carbon, OH on a carbon. The functional group depicts... The chemical reactivity of those atoms.
This OH group reacts totally different than this phenol group right here. This phenol will not get you drunk whatsoever. Horrible other things will happen. This OH group does. So the difference between them and their chemical reactivity differences give them two different functional group names.
So we have a phenol and an alcohol. Excuse me. Now, starting to get a little bit more advanced.
We're going to look at ethers. An ether is a carbon connected to an oxygen connected to a carbon. Now we're going to see later on what are some... the restrictions on the neighboring carbons of an ether. But for right now, we're just going to put little arrows next to this and just say, to be continued.
I'll put a little star right here when we get down to the esters down below. Alright, the next one that we're going to talk about. is a thiol, where you have a hydra or a sulfur attached to a carbon.
It doesn't have to be sp3 hybridized. And that is a thiol right there. We don't have a, well we do have the corresponding arine thiols, but we're not going to touch that in this class right here. After that we have something called a sulfide, and we're going to notice how it looks very similar to the ether over on the other side.
Wow, very interesting. Go ahead and put some stars next to those carbons. And then this last one right here on this row is a disulfide, where it's a carbon attached to a sulfur attached to a sulfur attached to a carbon.
Now, these carbons right here, we're also going to give some indications on. So what is all those little stars representing right here? What that is telling us, and I'm just going to go ahead and just verbally say this is, is that those carbons cannot contain any other oxygens or sulfurs.
They are just carbons with... hydrogens on them or other carbons. So the carbon with the asterisk has other carbons attached or hydrogens. Nothing else. That's going to be very, very important.
Let's go ahead and shrink this down a little bit and move it up right over here. Now, why is that so important? Here's a carbon connected to an oxygen connected to a carbon.
That's great. That looks just like the ether up above. But now I'm going to put a carbon oxygen double bond. And this functional group is called an ester. The chemical reactivity of an ester versus an ether are totally different.
Oh, and please forgive me, I misspelled ester right there. I put an H in it. I am the world's worst speller.
The difference between the ether and the ester is that carbon-oxygen double bond, what we commonly call a carbonyl group. Now, it's not a functional group. A carbonyl is kind of like slang terminology.
It just means that there's a carbon-oxygen double bond. So an ester contains a carbonyl as a part of its structure. We're not going to see those carbon-oxygen double bonds in the sulfides and disulfides in this class as of this point.
We might later on. Excuse me. Now, continue. Excuse me, had to clear my throat. So now, the next functional group we're going to talk about.
It's going to be a carbon. connected to an NH2 group, and this is called an amine. An amine is basically just a nitrogen attached to carbon and hydrogen.
Let me say that again. An amine is a nitrogen attached to carbon and hydrogen. How many is going to dictate if it's a primary amine, secondary amine, or tertiary amine, and we'll cover that later on in another video, but that's an amine.
Now, remember the difference between an ether and an ester is just a carbonyl. What if we put a carbonyl on an amine? So here is this NH2 connected to a carbon. This right here is called an amide functional group.
Now notice I just put this little line right here. I'm just putting off saying don't forget that carbon has other bonds on it. But just to keep up what we're doing up above, I'm going to go ahead and erase it. We have to have the octet rule satisfied for carbon. So an amide group has a carbon-yield group with a nitrogen on it.
Now the nitrogen can have two hydrogens on it, or it can have a carbon and a hydrogen, or two carbons, or three carbons, or three hydrogens, any combination. And that gives us different types of amines that we'll learn later on. Now the chemical reactivity of an amide versus an amine is completely different, and that's why they have two different functional group names. The next one that I'd like to talk about is a carboxylic acid.
And this is going to be an important functional group in this class and in our bodies. A carboxylic acid is going to have a carbon that has an OH on it. Oh wow, that means it's kind of looking like an alcohol.
But the carbon of that is going to be bound to a carbonyl. So if we notice the difference here, OH on a carbon looks like this alcohol, but this carbon is sp2 hybridized connected to this carbonyl. And that's what makes up the carboxylic acid functional group. Wonderful.
Now, directly underneath that, I'm going to bring this down a little bit more, I'm going to put another carbonyl in, attach it to another oxygen, and attach it to another carbon. Wow, that looks like I'm making an ester functional group. And that would be an ester as shown, but now I'm going to put another carbonyl in.
Notice, I have a carbonyl, oxygen, carbonyl flanking each other. This right here is the carbon. Here is called an anhydride.
And that is another functional group that we are going to be seeing in this class. Now, there are other functional groups in organic chemistry, but these are some of the big ones that we're going to see. And the very last one I want to show you is just one class just by itself, and that is called the nitro group. A nitro group is going to be connected to a carbon with an NO2 group attached.
And what I encourage you to do right now is try to draw the Lewis dot structure of a nitro group and figure out any formal charges in it. This is going to help us later on when we're covering some arene chemistry and how it might direct the ring in terms of chemical reactivity. So it's a good exercise to practice right now that will help us later on.
So right here, what we're seeing is the wonderful world of organic chemistry functional groups. This is not all of them. There are a lot more.
And as I'm saying that, there's two more I forgot to mention, two of the big ones that we really care about. The first one is a carbon yield with a hydrogen on it connected to another carbon. Now, I don't want to just say carbon here, so I'm going to erase that.
I'm going to write R. This R represents hydrogen or carbon. Now, if I draw R connected to a carbon yield, oops, and let's go ahead and...
show the carbon like I'm doing before connected to another R, I'm going to implicitly state here that these R's are carbon. How similar are these two groups? Extremely similar.
Here R group, R group, the only thing difference is this is a carbon, this is a hydrogen. This one on the far left is called an albohide functional group, so it has to have a hydrogen on the carbon of the carbonyl, and the one next to it is called a ketone. And those are two very important carbonyl types of molecules.
There's some other ones like acid chlorides that we'll talk about later on, but this kind of encompasses and shows us all the key functional groups in organic chemistry that we're going to be covering this semester and that's applicable for your majors. I hope each of you are doing well. I look forward to talking to you in office hours or discussion sections, and I hope you're all having a wonderful day.