organic chemistry question

[mangos3]

Advertisement - Members don't see this ad

Can anyone explain the general rules for acidity/basicity of an organic molecule and how this relates to electron-donating or electron-withdrawing groups that are attached? Do electron-donating groups stabilize or destabilize the anion? I'm a little confused on this point and I always get the rules mixed up. Thanks!

 

[rgerwin]

So, withdrawing groups, which often include oxygen(electronegative) will stabilize the ion, making it more acidic. This is especially true for the alpha carbon of a ketone. Donating groups will usually decrease the acidity, and deactivate a benzene ring.

 

[carn311]

You MUST look at this book...

it gives the most concise and thorough explanation of acid base chemistry I've seen. It will be an asset to you throughout the entirety of the two courses.

 

[ilovehedgehogs]

So, withdrawing groups, which often include oxygen(electronegative) will stabilize the ion, making it more acidic. This is especially true for the alpha carbon of a ketone. Donating groups will usually decrease the acidity, and deactivate a benzene ring.

I agree with the first part, but electron donating groups (R, NR2, OR) activate a benzene ring and cause additions to be made ortho/para, while electon withdrawing groups (COOH,COOR) deactivate the ring and cause additions to be made meta

 

[mangos3]

ok, that makes sense. thanks!