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Topic: HNMR spectrum interpretation  (Read 4219 times)

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Offline tiff8968

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HNMR spectrum interpretation
« on: April 14, 2009, 08:57:27 PM »
I have a HNMR spectrum of an compound I want to identify and it has numerous peaks someone told me the peaks reperesent the different number of hydrogens in the unknown compound is that true. If so my compound has 43 hydrogens is that possible???

Offline miss_molecule

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Re: HNMR spectrum interpretation
« Reply #1 on: April 15, 2009, 12:02:19 AM »
Hi!
You have to messure the integrals of each peak. Then these integrals will give you the number of hydrogens. start with a peak you know is e.g. 2 hydrogens. divide the integral by 2, and you will have the number for one hydrogen. If you divide each integral by this number, you will get the number of hydrogens in each peak:)

Offline James Newby

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Re: HNMR spectrum interpretation
« Reply #2 on: April 15, 2009, 08:17:41 AM »
Is your NMR data real or is it a question from a professor/teacher?  Can you post the spectra?

Each peak from the baseline corresponds to a proton environment.  If the peaks splits into a pattern this gives information on what is near the proton environment.

eg methane will give one signal as all the protons are in identical environments

ethanol CH3CH2CHOH example:

CH3CH2CHOH peak will be split into  3 by the protons next to it.
CH3CH2CHOH peak will be split by the CH3 group and the proton CHOH.  This will give 8 peaks
CH3CH2CHOH peak will be split by CH2 into 3 peaks.
CH3CH2CHOH peak will give 1 peak as the proton environments are further away.  This peak may or may not show,alcohols are a bit strange.

So a simple molecule like ethanol with 7 protons will give 14-15 peaks in 4 places.

How much NMR have you studied?  I don't want to add further confusion without knowing what you have studied.  Apologies if you already know this stuff
4th year undergraduate at the University of Sheffield

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