Help with this NMR spectrum

[zuriel]

Hi everyone,

 

I'm learning NMR at the moment and I understand it relatively well - but I have a problem with this spectrum here and it's been bugging me for so long. Can anyone possibly offer some explanantion to me ?

 

The compound is 2-methylpropan-1-ol :

 

 

As you can see, there are 4 "types" of proton - the 'OH' the 'CH2' the 'CH' and the two chemically equivalent 'CH3's

We'd expect 4 proton resonance signals and this is the case, (see spectrum here) :

 

http://www.sigmaaldr.../FNMR000946.PDF

 

I understand the doublet for the CH3, the triplet for the 'CH2' and 'OH' (if OH coupling occurs) but I don't understand the clear SEPTET for the 'CH' - because I'd expect a nonet!

Does anyone have any idea why this might be the case in this spectrum? Could it be something to do with J values? Could there be a spectrum error?

Any help would be greatly appreciated with this - it's driving me crazy! lol

Edited March 7, 2012 by zuriel

[hypervalent_iodine]

If you look closely along the baseline, you'll see that it is a nonet. The peaks are a bit tiny because of how huge the methyl peaks are, but they are definitely there.

[zuriel]

You're most certainly correct - thanks for the help!