The Best Way to Read a gCOSY Spectrum

We can summarize what we have just discovered the 2-D gCOSY spectrum allows us to determine more precisely the chemical shifts of resonances that overlap in the 1-D NMR spectrum. 

If we now start at 2.43 ppm on the diagonal, we can move upward to find the two cross peaks that correspond to HS q and HSgx- Given our expectation that H5gq will resonate downfield from H5ax we 

We have now assigned all of the resonances of ethyl nipecotate, and we leave as an exercise the identification of the cross peaks between the resonances from the H4 s and H5 s. 

Just as we did for the resonances, the order of the chemical shifts (left to right, highest ppm to lowest) can be written 

As we did for the resonances, we can make a table (Table 9.2) listing the shifts and intensities we predict for the resonances. We could, of course, consult published tables. 

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