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Topic: NMR Coupling Pattern (doublet of quartets?)  (Read 5560 times)

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Offline radical

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NMR Coupling Pattern (doublet of quartets?)
« on: October 08, 2015, 02:28:01 PM »
Hey guys, I'm just wondering what the coupling in this H1 NMR is. I'd say a doublet of quartets - 1st quartet is peaks 1, 2, 3 and 5. 2nd quartet is peaks 4, 6, 7 and 8. However this doesn't make sense with the rest of the spectrum so I think I must have got this wrong. Any ideas what else it could be?


Offline Babcock_Hall

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Re: NMR Coupling Pattern (doublet of quartets?)
« Reply #1 on: October 08, 2015, 05:05:37 PM »
Is it possible that you have two quartets that overlap somewhat?

Offline Dan

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Re: NMR Coupling Pattern (doublet of quartets?)
« Reply #2 on: October 09, 2015, 02:08:52 AM »
I'd say a doublet of quartets - 1st quartet is peaks 1, 2, 3 and 5. 2nd quartet is peaks 4, 6, 7 and 8.

That's what it looks like to me too.

Quote
However this doesn't make sense with the rest of the spectrum

How so?

Can you give more structural details?
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Offline ATMyller

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Re: NMR Coupling Pattern (doublet of quartets?)
« Reply #3 on: October 09, 2015, 03:33:38 AM »
Looks like a doublet of quartets to me, but in theory could also be two separate doublet of doublets. Do you have integration values for the peaks?
Chemists do it periodically on table.

Offline Irlanur

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Re: NMR Coupling Pattern (doublet of quartets?)
« Reply #4 on: October 09, 2015, 02:46:33 PM »
I'd go for a doublet of quartets or very bad luck.

Offline Babcock_Hall

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Re: NMR Coupling Pattern (doublet of quartets?)
« Reply #5 on: October 09, 2015, 05:20:18 PM »
If one had two ethyl groups that had similar chemical shifts, it seems to me that one would see two quartets close together.

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