Apparently the NMR of the methyls of N,N-dimethylnitrosamine isomers show a different chemical shift in NMR, which can lead to coalescence depending on temperature.

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Since the molecule is symmetric on one side I don't understand how cis-trans isomery would lead to different chemical environments?

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    $\begingroup$ "Since the molecule is symmetric on one side" Do you mean that it has planar symmetry? One methyl group is cis to the oxygen, the other trans. They are in very different environments. $\endgroup$
    – Buck Thorn
    Commented Apr 20 at 13:45
  • $\begingroup$ I think Buck Thorn's comment answered your question. Also, would you please put the temperatures at each of a, b, c, d, and e to be clear for the readers? $\endgroup$ Commented Apr 20 at 19:39


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