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Shristy posted an Question

July 26, 2020 • 17:01 pm

30 points

IIT JAM
Chemistry (CY)

What is persistant radicals and captodative effect ??

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Suman Kumar

When EDGs and EWGs are near the radical center, the stability of the radical center increases.[1] The substituents can kinetically stabilize radical centers by preventing molecules and other radical centers from reacting with the center.[3] The substituents thermodynamically stabilize the center by delocalizing the radical ion via resonance.[1][3] These stabilization mechanisms lead to an enhanced rate for free-radical reactions.[
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In the figure at right, the radical is delocalized between the captor nitrile (-CN), and the dative secondary amine (-N(CH3)2), thus stabilizing the radical center
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Dinesh khalmaniya 1 Best Answer

Both ERG and EWG increase the stability of free radical because in both the case overall energy decrease so stability increase. it is known as captodative effect
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sir but generally ERG increase the stability of free radical ?
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no both increase
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check it
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got it??
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S
Suman Kumar

persistent radical effect (PRE) in chemistry describes and explains the selective product formation found in certain free-radical cross-reactions
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Persistent radical are very stable radical. They are used as an intermediate for organic synthesis
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For captodative effect
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Dinesh khalmaniya 1

persistent radicals are those which are highly stablised. for example triphenyl methyl radical which is stabilized resonance.
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check it
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got it??
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Then give some examples of erg and ewg of radicals....
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