June 25, 2024, 02:35:00 PM
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Topic: Homework help-NMR spectroscopy  (Read 2128 times)

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Offline jjFrank

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Homework help-NMR spectroscopy
« on: April 28, 2024, 04:24:03 PM »
The proton-decoupled 13C NMR spectrum of
2,4-pentanedione consists of six lines (Ġ 24.3, 30.2, 58.2, 100.3,
191.4, and 201.9 ppm), not the “expected” three lines. Explain.

I'm confused because to me it should be 3 lines since it is symmetrical. What concept am I missing??

Thank you,
Jingxuan

Offline rjb

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Re: Homework help-NMR spectroscopy
« Reply #1 on: April 28, 2024, 05:30:05 PM »
Hi J,

I'm guessing here, but if my guess is right, then it might be worth looking up the term 'tautomer' (wikipedia will do fine) and considering how this might apply to ketones and therefore to the NMR results for pentanedione...

Kind Regards

R

Offline Aldebaran

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Re: Homework help-NMR spectroscopy
« Reply #2 on: April 28, 2024, 05:39:06 PM »
@op
Look it up on sdbs and you should be able to figure it out ok.

Offline Aldebaran

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Re: Homework help-NMR spectroscopy
« Reply #3 on: April 28, 2024, 05:43:03 PM »
Ah I see rjb got their before me 🤢

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