Aug 26, 2014
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I attached an image for the nmr of 2-pentanone and I do not understand why there is a sextet. On my other attached image, Hc would be split by both Hd and Hb. I don't understand why this would be a sextet if it is being split by two unequivalent hydrogen groups within a 3 sigma bond distance. On the NMR, for Hc why do we not see a triplet of quartets, or a quartet of triplets? I'm probably missing something here. Some help would be very appreciated! Thank you
 

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SpaceBuff12

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The Hc hydrogens have 5 neighboring hydrogens on adjacent carbons. Using the n+1 rule you would expected a signal with six peaks.

Edit: For clarification, the fact that Hb and Hd hydrogen atoms are non-equivalent is irrelevant for the MCAT.
 
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Aug 26, 2014
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So when would non-equivalent hydrogens become relvant in terms of complex splitting patterns?
 

chemtopper

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The Hc hydrogens have 5 neighboring hydrogens on adjacent carbons. Using the n+1 rule you would expected a signal with six peaks.

Edit: For clarification, the fact that Hb and Hd hydrogen atoms are non-equivalent is irrelevant for the MCAT.
Yes right it is Hc which splits with n+1 rule and MCAT exam will not test you for complex splitting.