Nucleophiles and Basicity

Now I want to go into nuclear files because remember that I said you have to define nuclear falls more than just saying negative is strong and Neutrals Week. So I want to remind you guys of what's the difference between a nuclear file and a base? Because that actually is gonna matter for this section. Okay, this section has a lot to do with conceptual questions that once again, you could get in this chapter. And what a what a nuclear follows, If you remember that had to do with Louis definition of acids and bases. Okay, so I'm just gonna put your nuclear fall. Is the Lewis definition. Wow. Okay. Johnny can't spell Lewis, okay? And what that means is that it's a good electron donator. Okay, so remember that basically, if you can donate electrons easily, that's a good nuclear file. Okay, what's a good base? Well, a base is the bronze, said Lowry definition. Okay. Remember what the bronze said Larry definition is that you're a good proton, except er okay, now. Ah, lot of times a good electron donator is also gonna be a good proton. Except er so a lot of times, these things are the same nuclear Felicity and basis city have a lot of cross over. But there are gonna be some instances where one of the things gets better and the other one doesn't or even the other one gets worse. It might get better at donating electrons, but worse it pulling off a proton on. I'm going to show you guys. How so? This is the way we determine the rules. The first rule is actually that generalization that I told you guys earlier, which is just that if you have a negative charge, that's always going to be stronger nuclear file than neutral. So that's when I said basically strong versus week. Okay, so you guys already knew the first rule just from me telling you guys that. But there's actually two more rules that you guys need to be aware of. Okay, So the second rule is that the bulky or the substrate? Okay, if you have a very bulky nuclear file, that's gonna make it more basic and less nuclear Filic. Okay, so what am I saying there? Okay, What I'm saying is that if you have a really bulky, negatively charged compound, let's say okay, that means that it's gonna be worse at donating electrons. Why? Because it's kind of a more difficult time approaching Electra files, because now it's gonna be so bulky. Okay, so it's actually gonna be worse it donating electrons. But it's actually gonna be better at pulling off protons. Why? Because protons typically are at the edges of molecules, so it's easy for it to access a proton. But it's hard for it to donate electrons. Does that kind of makes sense? This is going to come into play later when we talk about elimination reactions and bases that favor elimination. Because, remember, elimination is about the base, not the nuclear file. It's about pulling off a proton, all right, and then, finally, this is our last rule that you need to know. And then we'll be done with nuclear files, which is that basis city and nuclear Felicity almost always go in the same direction. So as you can see as I go towards less Electra negative my basis and a nuclear files get stronger. Okay. And then also, as I go up my periodic table, my bases and my nuclear falls get stronger. That has to do with the size effect. Remember that. So basically as you go up, you're gonna be better. It donate electrons because you're smaller, so you don't like them as much. Okay, that's kind of the point. And here I have a little drawing to show that, but it turns out that there is going to be an exception to the rule. And the exception comes with products, Solvents. So, as you can see it in a product solvent, this is what the nuclear files look like. They just look naked. Okay, I'm just gonna put here there naked. Okay. Pretty scandalous. There's nothing around them shielding them or whatever. Okay, but then if you have a product solvent, what did I say about products? Solvents? Well, product solvents, if you guys need to be reminded, are solvents that can hydrogen bond if you can. Hydrogen bond thes air solvents that are typically attracted to charges. So they're attracted to positive charges and negative charges. So what they're going to do is they're gonna do something called solve ating. Okay? They're going to surround that negative charge. So here I've drawn a picture of water which can hydrogen on its pro dick salivating. Florian and salivating iodide. Floridian iodide. Okay. And what we find let me just move out of the way here for a second is that when you have a smaller and I am like Florian like fluoride, the the product molecules are able to surround it better and able to more tightly solve ated. So what that means is that it's gonna be a worse electron donor because it's so covered up. Okay, it's it's really solve ated. That's the word for it. Okay, solve it. It just means it's covered in all these water molecules. Okay. Whereas an I A diet is so much bigger that it's gonna be more loosely solve ated. It's gonna be more difficult for all the water to cover all the spots as a lot more surface area. So it's actually gonna be a better electron donor, even though it's a worst nuclear file. Okay, so it turns out that in a product, solve it I had died is actually gonna be your best nuclear file. Okay, so this trend is reversed, is you guys can see in a product solvent. This trend is reversed, but in in a product solvent, the trend is the way. It was a beginning which is just that f is the best nuclear file and I is the worst. Okay, so there's gonna be the one thing that you guys have to remember in terms of concept because you could get I see the kind of question, all time and all kinds of exams, all kinds of tests. Banks, where professors will ask, What's the best nuclear fault in a product solvent? What's the worst nuclear fall in a product solved? So you need to have these trends memories like the back of your hand to answer those kinds of conceptual questions. Now, does it matter so much for mechanisms? Not usually usually. Like I said, mechanisms aren't determined by solvents necessarily. But you should still know it because it's going to give you a better understanding of the content of this chapter. Alright, so I hope that made sense. Let me know if I can explain it any better, Make sure to ask questions. This is something that typically a lot of students feels a little bit confusing. I hope that my little drawing here that is actually like a new drawing I just made for you guys I hope that it will help. You guys kind of relate to what? I'm talking about a little bit better. Okay, so let's go ahead and move on to the next topic.