Resonance Stabilization

[deleted92121]

I have been working through the O-Chem as a Second Language to help with O-Chem and realized I am very lost when the resonance stabilization of a carbcation. What exactly is resonance stabilization? I am fairly comfortable with resonance but not really understanding this particular concept. Any help would be great.

Thanks,
DU

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[dranet]

Defns of Resonance include the sharing of electrons via pie bonds. It simply means that electrons that "belong" to an atom are able to move from their home or local atomic orbital to another adjacent atom's orbitals. They say they are "delocalised" then . With regard to Carbocations they are positively charged species with a full positive charge on the Carbon and where the hydrogen anion(s) has been lost or some other negatively charged group and then you have a central carbon atom with either 3, 2 or 1 carbon (R) groups attached. The Carbon has in effect an unhybridised p orbital in need of an electron. The connected R groups donate electrons towards the positively charged electron deficient central Carbon. It is similar to Resonance where electrons are shared or delocalised via pie bonds. The more electrons the R goups have to donate, by having more adjacent R groups surrounding the central Carbon the more stable that carbocation is 3>2>1> methyl. There is another term you might for this too and that is "hyperconjugation". Hope that helps. It is confusing when they say jargon that doesn't fit a defn . My native tongue is Italian and sometimes after years speaking english I think "what the !!!!!!!!".

 

[Ssina]

what s/he said, I like pictures, so here you go (sorry it's humongous! lol)

 

[MedPR]

I have been working through the O-Chem as a Second Language to help with O-Chem and realized I am very lost when the resonance stabilization of a carbcation. What exactly is resonance stabilization? I am fairly comfortable with resonance but not really understanding this particular concept. Any help would be great.

Thanks,
DU

Resonance occurs when pi bonds overlap and thus the electrons are delocalized across every atom in the resonance system.

In a carbocation, there is a carbon that is electron deficient. Resonance delocalizes the positive charge by "sharing" neighboring electrons with the electron deficient carbon. The electron deficiency is now reduced, thus stabilizing the carbocation.

 

[deleted92121]

Thanks for the help everyone. It makes more sense now understanding the delocalization.