July 21, 2011
When examining NMR data, it is important to understand that coupling constants and patterns can be misinterpreted. The following example is one that can be avoided.
For an unknown compound, the 1H NMR spectra below shows the same coupling pattern with different interpretations for the coupling constants. Spectra A relies on chemical shifts listed at 2 decimal places whereas spectra B displays them at 3 decimal places. Since the accuracy of the data is at a minimum of 3 decimal places, the better interpretation is seen for spectra B.