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Organic Chemistry

Blazing goIITian

Joined:	9 Mar 2008
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30 Jun 2008 21:03:30 IST

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501

nucleophilicity!

None

how nucleophilicity depends in polar aprotic i.e. non-polar solvents??

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Saurabh Sood

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Joined: 21 Nov 2007

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2 Jul 2008 11:40:40 IST

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Polar aprotic solvents are very effective in solvating cations, but not nearly so effective in solvating anions. Because anions are only poorly solvated, they participate readily in SN reactions, and
nucleophilicity parallels basicity: F- > Cl- > Br- > I-

Polar protic solvents anions are highly solvated by hydrogen bonding with the solvent the more concentrated the negative charge of the anion, the more tightly it is held in a solvent shell the nucleophile must be at least partially removed from its solvent shell to participate in SN reactions because F- is most tightly solvated and I- the least, nucleophilicity is I- > Br- > Cl- > F-

srikrish

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Joined: 30 Jun 2008

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2 Jul 2008 14:46:19 IST

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i think thegreatcheetah is right...

nucleophilicity is tendency of a group to attack a nucleophilic site...

a polar solvent solvates the nucleophile, whereas a polar aprotic solvent does not (a property of polar aprotic solvents)...

hence nucleophilicity is enhanced in polar aprotic solvents...

hope you got it ...

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