BRAINCAKENMR Spectroscopy
Revision notes for NMR Spectroscopy in AQA Chemistry (7405). Every lesson in BrainCake comes with R.E.C.I.P.E. recall steps, a quick check and spaced reviews.
- Nuclear Magnetic ResonanceNuclear magnetic resonance (NMR) spectroscopy is an analytical technique that gives information about the position of 13C or 1H atoms in a molecule.
- Chemical ShiftIn an NMR spectrum, the position of a peak is given by its chemical shift, symbol δ, measured in parts per million (ppm).
- The TMS StandardChemical shifts are measured relative to a reference compound, tetramethylsilane (TMS), Si(CH3)4.
- Deuterated SolventsNMR spectra are usually recorded with the sample dissolved in a solvent.
- 13C NMR Spectroscopy13C NMR spectroscopy gives information about the carbon atoms in a molecule.
- Interpreting 13C NMR SpectraTo 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.
- 1H NMR Spectroscopy1H NMR spectroscopy (proton NMR) detects the hydrogen nuclei in a molecule.
- Integration TracesIn a 1H NMR spectrum, the area under each peak is proportional to the number of H atoms in that environment.
- Spin-Spin SplittingIn a high-resolution 1H NMR spectrum, many peaks are not single lines.
- The n+1 RuleThe n+1 rule links the splitting of a 1H NMR peak to its neighbours: H atoms with n H atoms on the adjacent carbon(s) give a peak split into n + 1…
- Interpreting 1H NMR SpectraTo deduce a structure from a 1H NMR spectrum, combine all four pieces of information with the molecular formula: • Number of peaks: the number of H…
On the specification
- 3.3.15 Nuclear magnetic resonance spectroscopy