H NMR Help

[Psa]

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According to topscore this molecule will only have 2 singlets. Can someone explain why the 4 H's in the aromatic ring are considered a singlet? Shouldn't it be a doublet since each H in the ring has at least 1 neighboring hydrogen?

 

[SafetyDog]

There are only 2 groups: the H's on the aromatic and the hydrogens on the carbon attached the oxygen.

It's considered a singlet because they are all equivalent to each other and are part of the same group. Equivalent hydrogens don't alter the singlet/doublet thingie.

 

[Psa]

There are only 2 groups: the H's on the aromatic and the hydrogens on the carbon attached the oxygen.

It's considered a singlet because they are all equivalent to each other and are part of the same group. Equivalent hydrogens don't alter the singlet/doublet thingie.

I get that there are 2 groups due the symmetry of the molecule. But I still dont get why the the neighboring H's in the ring don't count.

 

[SafetyDog]

I'm pretty sure it's because equivalent hydrogens don't affect the multiplicity of the peak. Don't wanna give you the wrong answer though.

According to my notes on Chads: neighbors = nonequivalent hydrogens less than 3 bonds away.

 

[Psa]

I'm pretty sure it's because equivalent hydrogens don't affect the multiplicity of the peak. Don't wanna give you the wrong answer though.

I think i get it. You're saying that the whole benzene ring is considered a single group, just like the 3 H's in the methyl are considered one. I'm just confused because I thought that whenever the H's were on separate carbons, they always got the n+1 amount of peaks as the neighboring H's.

 

[hope_to_match]

for the benzene ring keep in mind that those double bonds are not fixed i.e. there is a delocalization of electrons and therefore you only see 1 H. i think thats why

 

[Psa]

for the benzene ring keep in mind that those double bonds are not fixed i.e. there is a delocalization of electrons and therefore you only see 1 H. i think thats why

I definitely remember chad mentioning that now! I need to re-watch some stuff b4 my test

 

[hope_to_match]

yup im rewatching certain sections as well for GC and OC! when is your test?

 

[Psa]

yup im rewatching certain sections as well for GC and OC! when is your test?

2 days

 

[hope_to_match]

oh good luck! how long have you been studying?