BRAINCAKEInterpreting 13C NMR Spectra
To work out a structure from a 13C NMR spectrum, use two pieces of information: the number of peaks and the chemical shift of each peak.
Step 1: count the peaks, ignoring TMS at 0 ppm. This gives the number of carbon environments. If there are fewer peaks than carbon atoms in the formula, the molecule must have some symmetry.
Step 2: match each shift to a type of carbon using the data booklet. Useful approximate regions:
• 5 to 40 ppm: C in an alkyl chain (C-C)
• 50 to 90 ppm: C bonded to oxygen (C-O), as in alcohols, ethers and esters
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More in NMR Spectroscopy
- Chemical Shift
- The TMS Standard
- Deuterated Solvents
- 13C NMR Spectroscopy
- 1H NMR Spectroscopy
- Integration Traces
- Spin-Spin Splitting
- The n+1 Rule
All 11 lessons in NMR Spectroscopy · All AQA A-level Chemistry topics