Nucleophile Base Strong Weak SN/E Reactions

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CANgnome

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Is there any sources where a complete description or list can be obtained for what is a strong base, weak base, strong nucleophile, weak nucleophile and the differentiation between them?

Especially the difference between base strength/nucleophilicity.

If there is any sources with a good list of commonly seen nucleophiles/bases for SN/E reactions, that would be wonderful too.


Thanks ahead of time.

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Is there any sources where a complete description or list can be obtained for what is a strong base, weak base, strong nucleophile, weak nucleophile and the differentiation between them?

Especially the difference between base strength/nucleophilicity.

If there is any sources with a good list of commonly seen nucleophiles/bases for SN/E reactions, that would be wonderful too.


Thanks ahead of time.

Main difference between base strength/ nucleophilicity is that base strength you are measuring the position of an equilibrium, while nucleophilicity is measuring a RATE (so we're talking about a difference between thermodynamics vs. kinetics). This makes nucleophilicity much more variable, since it can be affected greatly by both solvent and also the type of reaction involved. The classic example of a solvent effect is the reversal of order of nucleophilicity of the halides when you go from a polar protic solvent to a polar aprotic solvent. Type of reaction is also important: for instance, Grignard is great nucleophile for addition to aldehydes/ketones but crappy for SN2 (it tends to act as base). Tougher to quantify nucleophilicity because it's multivariable.

One good thing to remember is that the conjugate base is ALWAYS a better nucleophile: http://is.gd/cP8D5

I should write a post about this.
Hope this helps - James
 
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