NMR

[Dark Horse]

Hey guys, in the molecule phenol (C₆H₅OH)-A benzene ring with one of the H atoms substituted for an OH, how many carbon and hydrogen environments are there? Thanks

[dekoyl]

According to my teacher: 4 hydrogen and 4 carbon environments.

However, I can't see it

[chem-nerd]

C2/C6 equivalent (H's on these Cs are equivalent too)
C3/C5 equivalent (H's on these Cs are equivalent too)
C1
C4
and the H on the OH and the H on C4
therefore, 4 carbon environments and 4 H environments

[TrueTears]

According to my teacher: 4 hydrogen and 4 carbon environments.

However, I can't see it

As chem-nerd said:



On the 1st carbon atom, clearly the C is in a different environment because it is with an OH

Now on 2nd carbon atom, it has a single bond left of it and a double right of it. C6 also has this formation. 2nd C environment.

On the 3rd carbon atom, it has a double bond to the left and a single bond to the right. C5 same formation. 3rd C environment.

C4 is different from C1 because it is bonded to a H not a OH.

Hence 4 C environments.

[chem-nerd]

try not to think of those double and single bonds as being 'set' in place. they can move around the benzene ring (hence why it's usually drawn with a circle in the middle).

the different environments are produced by the different neighbours.
for C2/C6 they have a C-O on one side and a C-C on the other
for C3/C5 they have a C-C-O on one side and a C-C-C on the other
for C4 it has a C-C-C on both sides
and C1 is clearly different due to the O

it's the same for the H environments

[Mao]

here's a picture:

[Dark Horse]

Thanks guys, i get it now! =P