Looking along the x axis, we can see that several peaks were clustered together near 7 ppm and near 1.3 ppm. Similarly, there are a couple of carbons that show up at the same place in the 13C NMR spectrum.Īn HMQC experiment will help spread things out into two dimensions. Indeed, the 1H spectrum has some unique peaks but also a couple of large multiplets. There are lots of similar positions in this structure, so it may be hard to tell peaks apart in either the proton or carbon NMR spectrum. COSY spectra show 3-bond coupling (from H-C-C-H), whereas HMQC shows a 1-bond coupling (just C-H). Cross-peaks show which proton is attached to which carbon. In an HMQC spectrum, a 13C spectrum is displayed on one axis and a 1H spectrum is displayed on the other axis. Just as COSY spectra show which protons are coupled to each other, HMBC (and the related HMQC) give information about the relative relationships between protons and carbons in a structure.
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