Using curved arrows, show how the species in part (a) can...

Using curved arrows, show how the species in part (a) can act as Lewis bases in their reactions with HCl, and show how the species in part (b) can act as Lewis acids in their reaction with $\mathrm{OH}^{-}$ (a) $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{OH}, \mathrm{HN}\left(\mathrm{CH}_{3}\right)_{2}, \mathrm{P}\left(\mathrm{CH}_{3}\right)_{3}$ (b) $\mathrm{H}_{3} \mathrm{C}^{+}, \mathrm{B}\left(\mathrm{CH}_{3}\right)_{3}, \mathrm{MgBr}_{2}$

Using curved arrows, show how the species in part (a) can act as Lewis bases in their reactions with HCl, and show how the species in part (b) can act as Lewis acids in their reaction with $\mathrm{OH}^{-}$
(a) $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{OH}, \mathrm{HN}\left(\mathrm{CH}_{3}\right)_{2}, \mathrm{P}\left(\mathrm{CH}_{3}\right)_{3}$
(b) $\mathrm{H}_{3} \mathrm{C}^{+}, \mathrm{B}\left(\mathrm{CH}_{3}\right)_{3}, \mathrm{MgBr}_{2}$

Key Concepts

Curved Arrow Notation

Curved arrow notation is a graphical tool used in reaction mechanisms to illustrate the movement of electrons during the formation and breaking of chemical bonds. It involves drawing arrows from the electron-rich sites (donors) to electron-deficient sites (acceptors), thereby conveying the process of electron pair donation in acid-base reactions.

Mechanistic Representation of Lewis Acid-Base Interactions

Mechanistic representation in the context of Lewis acid-base interactions involves detailing how electron pairs are transferred between the reacting species. This includes using curved arrows to show the electron donation by the Lewis base towards the electron-accepting Lewis acid, a fundamental step in forming new chemical bonds and driving the reaction forward.

Lewis Acid

A Lewis acid is defined as a chemical species that can accept an electron pair from another species. This concept is crucial in understanding many reaction mechanisms where electron-deficient centers, such as positively charged ions or molecules with incomplete octets, attract electron pairs to form new bonds.

Lewis Base

A Lewis base is any species that can donate an electron pair to form a bond with a Lewis acid. In reactions involving bases, the availability of a lone electron pair is essential for the initiation of the bond formation, which is typically represented using curved arrow notation.

Transcript

00:01 We want to use curved arrows to show how the species in part a can act as lewis bases when they react with hcl.

00:08 And we also want to show how the species in part b can act as lewis acids when they react with hydroxide.

00:18 So now, if all these in part a are supposed to be acting as lewis bases, that means if they're going to act as a bronstead and lowry base, it's the same idea for lewis.

00:32 So that means we're going to want to accept some hydrogen from our hcl, at least in this case here.

00:45 So what we're going to do is we're going to take this lone pair, and we're going to come over here and still this hydrogen, just like we would in jinkem.

00:55 This is going to pop off.

00:57 And the reason why we use these loan pairs here on this oxygen is because there really isn't any other ones we could use.

01:04 So doing that is going to yield us the following.

01:10 So i'm just going to draw the bond line for this.

01:12 So it would be one, two carbons, and then it has a oxygen with a hydrogen.

01:20 It actually would have two hydrogens now, one lone pair, and then a plus charge.

01:24 So we get a pronated alcohol.

01:26 And then we would just be left with our chlorine that is negatively charged.

01:31 So we have that.

01:33 Now what about our next one? so if this is going to act as a base, so again, it's going to need to donate some lone pairs.

01:41 The only thing that's going to have lone pairs on here is that nitrogen.

01:44 So it's going to follow the exact same like we did before.

01:48 This is going to come over here.

01:50 Still, this hydrogen.

01:52 Remember, we use a double barbed arrow to show both of the lone pairs moving, and then those electrons are going to go back to our chlorine.

02:01 And that's going to result in us having.

02:04 So we have a nitrogen, two, methyl, on either side.

02:08 We have a hydrogen and we have another hydrogen.

02:12 And so if we were to do the formal charge on this, it would be positively charged now.

02:17 And then we would have our negatively charged chlorine right next to it.

02:23 And then lastly, let's see.

02:29 So here we're going to have a lone pair on our phosphorus.

02:36 So this is going to come out.

02:40 Take the hydrogen here so again we use the double barbed arrow to show that then the bond between the hydrogen the chlorine break so it goes towards the chlorine and then that's going to go so we have phosphorus we have the three methyl then we have a hydrogen coming off and so now this is going to be positively charged for the phosphorus and the chlorine is going to be negatively charged.

03:12 So that's going to be what we get for those first three, and then for the next ones we'll get.

03:22 So we're going to start with these acting as our acids now...

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