1. CH 9-7: Topic C NMR
13C NMR gives direct information about the number of non-equivalent carbons. ONE signal per equivalent carbon.
13C NMR chemical shift scale ranges from ppm, so signals from similar carbons are less likely to overlap.
Only the spinning nuclei of the 13C isotope gives an NMR signal (not 12C). Only 1% of all carbon in nature is the 13C isotope times less sensitive than 1H NMR.
Since only 1% of all C is 13C, no splitting is seen by adjacent carbons - very small probability that there will be two 13C carbons next to each other! Easier to interpret.
It is possible to observe H-C splitting which is very useful: (a) “Proton Decoupled” 13C NMR (no C-H splitting) (b) “Proton Coupled” 13C NMR (shows C-H splitting)

3. 2-butanol “Proton Decoupled” 13C NMR

4. 2-Butanol “Proton Coupled” 13C NMR
(solvent)