Cyclohexene radical isomers stability

In summary, the conversation discusses the three isomers of cyclohexene radical - cis-1,2-dimethylcyclohexene, trans-1,2-dimethylcyclohexene, and 1,3-dimethylcyclohexene - and how they differ in stability due to their spatial arrangement and position of methyl groups. It is mentioned that 1,3-dimethylcyclohexene is the most stable due to its equatorial methyl groups, and this stability affects the reactivity of the isomers. Factors such as substituent arrangement, electron-donating/withdrawing groups, steric hindrance, and delocalization also contribute to the stability. The stability
  • #1
sludger13
83
0
The enthalpies of creating a cyclohexene radical isomers are:

ORTHO: 444 kJ/mol
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META: 361 kJ/mol
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PARA: 401 kJ/mol
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The meta-isomer is most stable (that is the reason for the formation of meta product in radical addition). Para/meta isomers energies seem obvious - both carbons are equivalent, only the meta-carbon participates in multiple bond, para-carbon doesn't.
I can't see why the ORTHO-isomer is the least stable one. The (.CR3) radical should rather be more stable than (.CHR2). What do you think?
 

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  • #2
Figured out, the PARA isomer has greater degree of hyperconjugation than ORTHO isomer.
 

FAQ: Cyclohexene radical isomers stability

What are the different isomers of cyclohexene radical and how do they differ in stability?

The three isomers of cyclohexene radical are cis-1,2-dimethylcyclohexene, trans-1,2-dimethylcyclohexene, and 1,3-dimethylcyclohexene. These isomers differ in their spatial arrangement and the position of their methyl groups, leading to variations in their stability.

Which of the cyclohexene radical isomers is the most stable?

The most stable isomer of cyclohexene radical is 1,3-dimethylcyclohexene. This is due to the fact that it has two equivalent methyl groups in the equatorial position, leading to a more stable conformation and reduced steric hindrance.

How does the stability of cyclohexene radical isomers affect their reactivity?

The stability of cyclohexene radical isomers directly affects their reactivity. The more stable the isomer, the less reactive it is towards addition reactions. This is because stable isomers have lower energy levels and are less likely to undergo reactions to achieve a more stable state.

What factors contribute to the stability of cyclohexene radical isomers?

The stability of cyclohexene radical isomers is influenced by various factors such as the spatial arrangement of substituents, the presence of electron-donating or withdrawing groups, and the overall steric hindrance. Additionally, the stability is also affected by the delocalization of the unpaired electron in the molecule.

How can the stability of cyclohexene radical isomers be determined experimentally?

The stability of cyclohexene radical isomers can be determined using various experimental techniques such as NMR spectroscopy, electron paramagnetic resonance (EPR) spectroscopy, and computational methods. These techniques allow for the observation and measurement of the energy levels and reactivity of different isomers, providing insight into their stability.

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