Carbon 13 NMR (phenolphthalein)

Hi

Phenolphthalein has 12 peaks but I only got 11. I am just confused b/w Carbons
.I think that they both are in the same environment but actually, they dont....can someone please explain that to me ?

Reply 1

Qer

OP

16

I am confused with 5 and 6. As mentioned above I think that they are same both 5 and 6 is attached to C-H.............

Reply 2

MexicanKeith

12

Original post by Qer

I am confused with 5 and 6. As mentioned above I think that they are same both 5 and 6 is attached to C-H.............

It's all about symmetry. You're right that they are in similar environments, so they will have similar chemical shifts, but they aren't in the exact same environment you can see that 6 is closer to the carbonyl group than 5, this means it isn't equivalent.

For both carbon-13 and proton NMR the carbon/proton on positions 5 and 6 will appear separately because, although they have similar environments, they arent the same

Reply 3

Qer

OP

16

Original post by MexicanKeith

It's all about symmetry. You're right that they are in similar environments, so they will have similar chemical shifts, but they aren't in the exact same environment you can see that 6 is closer to the carbonyl group than 5, this means it isn't equivalent.

For both carbon-13 and proton NMR the carbon/proton on positions 5 and 6 will appear separately because, although they have similar environments, they arent the same

thanks for the explanation

it makes sense

Reply 4

Qer

OP

16

Original post by MexicanKeith

It's all about symmetry. You're right that they are in similar environments, so they will have similar chemical shifts, but they aren't in the exact same environment you can see that 6 is closer to the carbonyl group than 5, this means it isn't equivalent.

For both carbon-13 and proton NMR the carbon/proton on positions 5 and 6 will appear separately because, although they have similar environments, they arent the same

Hi
i need help in this question

the number of peaks is 9 and i got 8 have a look please

Reply 5

MexicanKeith

12

Original post by Qer

Hi
i need help in this question

the number of peaks is 9 and i got 8 have a look please

CH3 groups on the benzene ring

Reply 6

Qer

OP

16

Original post by MexicanKeith

CH3 groups on the benzene ring

thanks!

Reply 7

Qer

OP

16

Original post by MexicanKeith

CH3 groups on the benzene ring

This is second part of this question

can you explain this question and what is protonated mean here?

Reply 8

MexicanKeith

12

Original post by Qer

This is second part of this question

can you explain this question and what is protonated mean here?

you can google, and probably guess what protonated mean, literally, gaining a proton

A + H⁺----> AH⁺

Then you would say chemical A has become protonated.

So things become protonated when they react with an acid, to become protonated the atom need to be able to donate a pair of electrons to the proton (H⁺).

The two nitrogen atoms each have a lone pair they could donate, the question is which one will become protonated (ie, which one can donate its lone pair most easily)

You should hopefully know something about amides and delocalisation that cold help you get the answer?

Carbon 13 NMR (phenolphthalein)

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