Both recrystallization and sublimation have been tried, and i took the Mass Spectra after the aforementioned purification methods, the molecular weight is right and from the Mass Spectra i can only observed my compound's peak and its isotopes. Then i moved to the NMR, it is blurred, even the number of H is not right.
Both recrystallization and sublimation have been tried, and i took the Mass Spectra after the aforementioned purification methods, the molecular weight is right and from the Mass Spectra i can only observed my compound's peak and its isotopes. Then i moved to the NMR, it is blurred, even the number of H is not right. Is there anyone encountering similar problems?? Can you give me some advice of purification??
Picture of NMR might help along with structure. Not sure what you mean by ”blurred”.
Are you sure you are integrating correctly? How many H’s do you expect and how many do you get after integration?
Greg Petruncio Thank you for your help, the integration of the H is not correct...
I expect to get 33 H in aromatic ring, but there are only 29-30 H, the number of H in aliphatic moiety is right. BTW, the overall structure of molecule is asymmetric. I also try to increase the temperature during testing the NMR (to help the splitting).
I think what you mentioned is lower number of Hs than the expected compounds. In my opinion thins has nothing to do with purification go and try the reaction (if it is) or the extraction again or report the compound as it is. However, if you think there is impurity there shall be extra Hs instead of lower number of Hs. Yet, if you like to proceed with purification try column/Plate chromatography. I hope this might help.
Mohammed Bule I have recalculated the number of Hs, approximately right.
yes, column chromatography has been conducted before the sublimation.
through these series procedures, I normally get up to 95% purity, at least the NMR is clear to identify all the peaks.
the NMR is also attached, but everything just mess up together.
Jie yan I don't see a problem with the NMR, it looks okay. Can you please check the integration? I mean if the reference proton is the right proton since that might affect the number of protons. If possible you can provide the structure and I can say something based on the structure.
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