MermaidWonders said:Stupid question here, but why wouldn't it be possible for $C{H}_{3}Cl$ to act as a nucleophile also since it has a nucleophilic site at the chlorine due to it being negatively-polarized when attached to methyl group?
I like Serena said:With the chlorine bound to the methyl group, it's single valence electron is near the methyl group.
Consequently, on the outside of the molecule, the chlorine is slightly positive charged, and attracts an electron.
It makes the molecule as a whole an electrophile.
If the chlorine atom would actually bind a lose electron, it would detach itself and form a $\ce Cl^-$ ion, which is a nucleophile.
MermaidWonders said:Wait... doesn't the polar bond between C and Cl result in Cl being negatively-polarized?
I like Serena said:A $\ce Cl$ atom on its own is neutrally charged.
When it bonds to $\ce C$, the electron in its outer shell moves to the $\ce C$ atom.
So it's indeed negatively polarized near the $\ce C$-atom, but at the same time it is positively polarized on the other side, which is the outside of the molecule.
Attractions to other particles happen on the outside of the molecule.
MermaidWonders said:Ah, I see now. :) So if the whole molecule is an electrophile overall, is there a case where the Cl atom serves as the electrophilic site? It's just that with the problems I've encountered so far, I'm used to seeing the C atom acting as the electrophilic site and Cl the nucleophilic site but never the Cl atom yet...
I like Serena said:A $\ce{Cl}$ atom doesn't (normally) occur on its own. If it does we call it a radical meaning it will immediately react with anything that comes nearby.
Instead we'll either have a $\ce{Cl2}$ molecule, which is electrophilic.
Or we'll have a $\ce{Cl-}$ ion, which is nucleophilic.
Electrophiles are molecules or ions that are electron-deficient and tend to accept electrons from other atoms. Nucleophiles, on the other hand, are molecules or ions that are electron-rich and tend to donate electrons to other atoms. In other words, electrophiles are electron acceptors while nucleophiles are electron donors.
Electrophiles and nucleophiles react with each other in a chemical reaction called a nucleophilic substitution. During this reaction, the nucleophile attacks the electrophile, forming a bond and replacing a leaving group in the electrophile. This results in the formation of a new molecule.
Some common electrophiles include carbocations, carbonyl compounds, and positively charged metal ions. Examples of nucleophiles include amines, alcohols, and negatively charged ions such as halides and hydroxide.
Electrophiles typically have a positive charge or a partially positive charge, and they are often electron-deficient. Nucleophiles, on the other hand, usually have a negative charge or a partially negative charge, and they are often electron-rich. Additionally, molecules with highly electronegative atoms, such as oxygen or nitrogen, are usually nucleophiles.
Yes, electrophiles and nucleophiles are commonly used in organic synthesis to create new molecules by forming and breaking bonds. For example, nucleophilic substitution reactions are often used to introduce new functional groups in organic molecules.