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I think I have figured out the IR spectrum for benzophenone. Would it be that the sharp peak in the middle (1700 cm^-1) is for the ketone and the little peaks pass 2900 cm^-1 rang are the sp2/sp3 carbons from the benzene rings?

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Also, I have an H-NMR spectrum for the same compound and I know there are only three peaks because the compound is symmetrical. But I am confused on how to determine the J values for each hydrogen.

enter image description here

Can someone kindly assist?

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  • $\begingroup$ If you print expanded portion with the resonance in Hz, you can easily calculate J values. $\endgroup$ – Mathew Mahindaratne May 7 '20 at 20:08
  • $\begingroup$ Can you explain what you mean? $\endgroup$ – Boo May 7 '20 at 20:11
  • $\begingroup$ Your peaks in the main spectrum is in $\pu{ppm}$. You have to print it again in $\pu{Hz}$ (there is a option to do so in printing software). Then expand it to be more clear. It is hard to read and isolate in compact mode. $\endgroup$ – Mathew Mahindaratne May 7 '20 at 20:15
  • $\begingroup$ Oh...I had to screenshot this photo because I was unable to save it correctly especially since it was given to me as a cropped photo. Because of this, I was wondering if I can figure the J values another way $\endgroup$ – Boo May 7 '20 at 20:26
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    $\begingroup$ Why do you want the J couplings? The assignment of all peaks is totally clear without, and the two triplets are higher order peaks anyway, so analysing the coupling is not trivial. $\endgroup$ – Karl May 7 '20 at 22:56

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