Structure, Bonding, and Stability of Carbocations

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Structure, Bonding, andStability of Carbocations
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Figure 4.8 Structure of methyl cation.

• Carbon is sp2 hybridized.All four atoms lie in
  same plane.

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Figure 4.8 Structure of methyl cation.

• Empty 2p orbital.
• Axis of 2p orbital is perpendicular to plane of
  atoms.

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Carbocations

• Most carbocations are too unstable to
  beisolated.
• When R is an alkyl group, the carbocation
  isstabilized compared to R H.

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Carbocations
Methyl cationleast stable
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Carbocations
H3C
H

C
H
Ethyl cation(a primary carbocation) is more
stable than CH3
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Carbocations
H3C
CH3

C
H
Isopropyl cation(a secondary carbocation) is
more stable than CH3CH2
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Carbocations
H3C
CH3

C
CH3
tert-Butyl cation(a tertiary carbocation) is
more stable than (CH3)2CH
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Figure 4.9 Stabilization of carbocationsvia the
inductive effect
positively chargedcarbon pullselectrons in ?
bondscloser to itself

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Figure 4.9 Stabilization of carbocationsvia the
inductive effect
positive charge is"dispersed ", i.e., sharedby
carbon and thethree atoms attachedto it
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