13. Alcohols and Carbonyl Compounds
Preparation of Organometallics
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Hey, guys. So now we're gonna talk about a topic that scares a lot of students, but it's really not that bad. Honestly, I think it's just the name that scares people. And the topic is Organa metallics. All right, so now you're thinking this is gonna be terrible. Organo metallic sound. Very confusing, but they're not. They're very easy, actually. All they are is there Alka leading agents. What is an Alka leading agent? It means that I'm gonna be able to use this re agent to put an alcohol group on something else. Okay, so it's the first thing, and what it's gonna be consist of is usually a group one A or to a metal. Okay, so I'm talking about the first in the second column of the periodic table. Those medals are gonna be directly bonded toe a carbon structure. Okay. Now, if you think about it, that's going to give this a very interesting molecular property, because typically, we usually see election negative atoms attached to carbon. Okay, um, there have been several instances this semester where you've been exposed to an election. Native Adam bonnets a carbon, for example. Dysfunctional group. Right here. See, with an X on it. Remember, X stands for alcohol. Hey, lied right? I'm sorry. Stands for halogen. So this would be an alcohol. Hey, lied. And what would be the typical die poll Oven alcohol? Hey, Light, Do you guys remember? Where would I draw the dye pulled towards towards the X. Right. So we get a die, pull towards the ex that's gonna give me a partial negative here. A partial positive here. What kind of charged by having that carbon? Well, we have a positive charge. Means that this carbon is gonna be a great Electra file. Okay? And that's typically the way that carbon acts. Ah, lot of re agents that we've seen this semester. Carbon is going to react as an electrified but organo metallics are different because notice that the X right X stands for halogen. What group is halogen in? Let's let's start off with carbon. Maybe this is a better explanation. Okay, Carbon, If I was just to draw my ghetto appear on the table that I do so often, Carbon is in group four. Are you cool with that? Halogen is all the way over here in group seven. So I'm just gonna draw seven. Okay, So which one is more Electra? Negative. Carbon or halogen? Obviously. The halogen. Right. Because as you move to the right in the periodic table, you get more Electra Negative. Okay. Are you guys getting this? So far, halogen fluoride flooring is very tops. That's obviously more election. Negative. But now let's think about thes medal thes organo medals that we're using for Agana Metallics. Well, I told you, these metals are usually in group one or group, too. So that means Are they gonna be on the right side or the left side of carbon? They're gonna be on the left side. So, actually, my medals, I'm just going to use the letter m to stand for them in general M because I don't know exactly which metal it is. It could be lithium. It could be magnesium, something like that. These were gonna be in group one or in groups to Okay, So which one is actually gonna be more Electra Negative. The carbon or the or the or the metal? And the answer is, the carbon will. So, Organa metals, like I have drawn here, I just put em in general because I don't know if it's lithium or magnesium, Whatever we'll get to the exact medals in a second, the typo goes in the opposite direction. So that means that instead, off this carbon being a great electrify, I'll organo metallics are examples of where your carbon is an amazing nuclear file and that's going to change everything. Oh, I wrote nuclear Filic. I was trying to write nuclear file. Okay, so the carbon is an amazing nuclear file because it has a negative charge now And that means that now I'm gonna be able to use this in a unique set of reactions because normally we don't have carbon with a negative charge. But now we do all right. So there's four types of organo metallics that you guys will be responsible for. There's four types that you need to know and they're commonly talked about inorganic chemistry. So the first one is sodium Alcon IEDs, thes air, the easiest type because most likely if you've been doing your homework, you've already seen one of these, at least okay, in another chapter. So the way that organo metallics work is we usually use a terminal alkaline terminal alkaline to react with a strong base. Okay, now that strong base, there's a lot of different strong basis we could use. But typically it's any NH two or any h okay. Thes basis. Have the ability to pull off. Let's just say amusing. NH two negative. They have the ability to pull off the most acidic hydrogen on that molecule. And when we learned in the acids in base chapter, how did predict acidity? We would have found that the H at the very end of that terminal al kind, is very acidic compared to the others. So I would grab that h with my base, and I would give a negative charge to my carbon. What does that mean? Well, that means that my final product is now gonna have a negatively charged carbon. Okay? And what is there a spectator? Ion? Yes. Remember that there was also an n a positive present. We just associate it that any positive can wind up making a bond to my negatively charged carbon. Now, this bond right here that I'm drawing and there's gonna be true with all the bombs were gonna draw today. This is an ionic bond. Do you remember what the definition of Ionic means. Okay, that's really easy. This is going back Thio, Chapter one. But in Ionic Bond was simply a bond that had such a great difference in election negativity that there's essentially no sharing. Do you remember that? Basically, that you can draw Bond, but really, there's very little sharing going on of electrons. Since this bond is Ionic, you can draw two different ways. You can either draw it as a bond like we've done here. Or you could also choose to draw it as ions with a negative there and with a positive there. Both of these representations are perfectly accurate because one of them shows that there is a bond. Okay, Ionic. But the other one shows how the bond is very weak, meaning that in week, in terms of that, it could be easily dissociated. Because I have almost full charges on both. Does that make sense, guys? And this is obviously a carbon here that is a carbon. I just didn't draw it, but it is carbon. Okay, so the reason to call this an organo metallic is because sodium is my metal. Okay, I remember that. I said the group one or two medals are typically your medals, so I could actually just boil this down to being are M. O K and R M is going to be the general. Um, the general structure that we're gonna use for all organo metallic so are simply means I have some kind of carbon group with a negative, and M means I have some kind of group one or two metal with a positive. Does that make sense? So this one is one that hopefully you've already seen by this point in the course. This is your first organic metal. Let's go into the next one. How if we want to make a grin yard regent Now, I know I might have just lost a few of you guys because that does not look like it says grin yard. It looks like it says Greg Nard, but it's pronounced Griner. OK, Just gotta live with that one. Just take it. Take it from me. I've been doing this for a while. So you got a granny agree, agent. And how do we make one? Okay, what we're gonna do, you don't need to know the whole mechanism. It's fine, but you do need to do is you need to recognize how to make it and what it looks like. Well, you start off with an alcohol. Hey, Light, start off with an Al Kyohei. Lied. Then what do we do? We add elemental meaning by itself. Magnesium, elemental magnesium. And what is this, E t two? Oh, what is that? That's an ether. Okay, because all that means is that I haven't Oh, in the middle with two ethyl groups coming off of it. So that would be di ethyl ether. Okay, so you put in elemental magnesium your diet for either. That's all gonna complex together. Then what you're gonna wind up getting is a Greg Nard Granier free agent. Okay, now, why is a green or gray agent considered in Oregon metallic? Well, because once again, we have the same situation. We have a carbon that has ah, carbon. That has a group one or two metal attached to it. Okay, if I were to draw that die poll, it would really give almost all of its electrons to that carbon. So I'd get a partial other negative here, and I'll get a positive there. Another way to write a green yard is to draw it ironically, so I'd have a negative charge here and then I would put MGB are or I said br because usually we use PR, but it could be any X with a positive. Okay. And these are associate together as an organo metallic. Is that cool? It's now it's another common one. Just you guys know X could stand for any halogen. Are you cool with that? I mean, usually we don't use Florin. Florin isn't used very commonly in these, but definitely iodine chlorine bromine are all fair game. Usually it's bro me, But you can also use the other ones as well. Cool. So let's keep going. So Organa lithium. Okay, so my organo lithium compound is gonna be super similar to my, um, to my green yard region. Okay, I'm just gonna use slightly different re agents. I'm going to start off with an Al Kyohei light again. No difference there. And now I'm gonna react it with two equivalents of elemental lithium instead of magnesium. And either Okay, what ones of happening is that? Now I just get my lithium directly attached to my carbon. That's it. There's no X on the other side. Okay, this could be written the other way, which would be Ionic. Right? Okay, so once again, this counts as an organo metallic, because I haven't our group with a negative charge and one of the group one or two medals with a positive charge. Okay, and then finally, we have Gilman re agents. Now, if the word gilman phrase gilman doesn't really ring a bell, maybe it's because in your textbook, they may not call it Gilman Regent. They may call it a lithium di alcohol coop rates. Okay. Really? I mean, they're the same exact thing. They just have One is named after the scientist, and one is just like the general name. Okay, but whatever. Regardless, these air the same exact thing. If you look online, let's say you're trying to find practice problems online, and you could totally look up Lithium Dioko cooperate, and they'll give you Kilman agents and vice versa. Cool. So you start off once again with an Al Kyohei lied and by a mechanism that you don't need to know. Okay? Please don't learn this right now. This is not what the point of this topic is. We're just trying to figure out what how to make them and what they look like. What we're gonna wind up getting is you combine to lithium in ether, so it's the same as really the same next step as the Organa lithium. But then you have a second step. The second step is the giveaway that it's Gilman. You have copper iodide. Okay, so you have See you, I copper iodide on. What that's going to do is it's going to take two of those organa lithium together and complex them toe one copper. So you're gonna wind up getting is now this structure right here. This is your lithium die alcohol Cooper or your Gilman re agent. And this still follows the general structure of RM organo metallic because I haven't our group that has negative charge. And then this copper would have a positive charge. Okay, Now I know that copper isn't group one or two, but there is a lithium there as well. So that's why I count it as a group one or two. Alright, guys. So what do you need to know here? What's the point of the story? The point of the story is no you're re agents to make thes reaction the's. No, no, the preparation step. Know exactly what free agents you need to make your again of metallics and then know how to recognize the names of each of those organa metallics. Okay, I haven't taught you how they react yet. We're gonna get there. But for right now, just know how to name it, how to make it. All right. Cool, guys. Let's go ahead and move onto the next topic.
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really quickly. I just want to talk about this blank space that we didn't fill out. I just wanna let you guys know that because organa metallics are strong nuclear files, that means that they're also gonna be able to react as strong bases. Okay, When you're strong nuclear file, you can usually directed a strong base. And that means you're good at pulling off. What? Protons. Remember that nuclear file is the Lewis definition. That means you're good electron pair donor. Okay, But when I say base, that's Bonds. Said Lowry. What I'm saying is that you're going to be a great proton, except er Okay, so how does that plans of things? Why is that important? Because you have to be aware of cross reactions with acidic hydrogen. So let's see that happen. Organo metallic rm. Right. Remember that. We've been using arm all day to me or get a metallic, and I introduce it to a molecule with and alcohol. Okay. And I introduced these to each other. Um, let's say that I want the organo metallic to react at some other part of the molecule. Okay, well, this would be a problem for me, Okay? The reason is because you guys might remember the hydrogen on alcohol is acidic. Okay, that's gonna be a problem, because my are is basic. It has a negative charge. So what you're gonna wind up getting is a mechanism where you're negative, winds up pulling off the H and attaching a negative charge to the O. And what you wind up getting is something that we consider a ruined organo metallic. Where you're going to get is an O negative. Okay? And then that's gonna be attached to, um, basically, it's just gonna be our h. So all we did here is we just protein ated the our group. And usually we don't want to Just protein eighth e argue. We wanted to react with something else, like an electro file. So this would be a really bad idea. Bad, sad face. Okay, Because I don't want just to get a negative charge and appropriated. Eight are what I'd prefer to get is to react with an electro file. Okay, e plus. Okay, so all I'm trying to say here is that you have to be very careful. About what? About alcohol's water, um, in particular. And then obviously car looks like acid stuff like that. All of these things you have to be very careful about because they have acidic hydrogen that can ruin that can mess up your organa metallic. And this is what we consider ruined. Okay, Even in your book, it's gonna talk about how ruining how you can ruin inorganic metallic by introducing it to one of those three things or just some kind of acidic proton, some kind of proton that has a plus charge. Okay, guys. So I just wanted to go over that really quick. Let's move on to the next topic.
Additional resources for Preparation of Organometallics
PRACTICE PROBLEMS AND ACTIVITIES (1)