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2D COSY and HETCOR explained

2D Correlated Spectroscopy (COSY) - homonuclear

Compares a spectrum with itself to look at how the peaks are correlated. This is an incredibly powerful tool that allows you to see which peaks are splitting which other peaks.

The way that we do this is as follows:

  • We ignore all of the peaks directly on the diagonal, as they represent self correlation
  • For every other point on the 2D map, we draw a line between it and whichever peak it intersects. This line indicates a correlation between the two (e.g. peak 6 and 1,3 are correlated, as is 13 and 1,3 )

2D Heteronuclear Correlated Spectroscopy (HETCOR)

Works in the same way as 2D COSY however it specifically looks at comparing the spectra of multiple different atom types to show how they are connected, i.e. If I plot a \(\hnmr\) and \(\cnmr\) spectra, which carbon are the protons attached to?