Re: TOJC benzene rings
lietkeam@plu.edu
Thu, 05 Dec 1996 17:31:22 -0800 (PST)
Kristina:
Dr. Fryhle explained this at today's problem session. The hydrogens
attached to an O or a N do not affect neighboring protons. The reason:
they are what are referred to as "exchangable protons", meaning the
molecule is most likely in equilibrium with a molecule where that proton
is dissociated from the O or N. That would result in a case where the
proton is not even bonded to the molecule, thereby providing no window of
opportunity to affect the protons the benzene ring. In simpler form, that
proton is so weakly bonded to the molecule, it has no chance to split the
nearby hydrogens.
-ahna
On Thu, 5 Dec 1996 hilleskl@plu.edu wrote:
>
> I am having trouble understanding why in monosubstituted benzene rings all
> of the H on the benzene ring are equivalent in H NmR? The problems in the
> book had the substituted group was a ch2 with an OH or ch3. Wouldn't the
> H's closer to the substituted group be different than those farther away?
>
> Kristina
>
>