Nuclear Magnetic Resonance (NMR)
• Some atomic nuclei, but not all, have a property
called “spin” which results in multiple energy states
when placed in a magnetic field.
• Atoms which are in equivalent environments in a
molecule behave equivalently.
• Anything near an electronegative element will
appear at a larger chemical shift.
• Peak areas approximate the number of atoms in a
• Hydrogen’s on adjacent carbons can affect each
other’s environment; splitting according to n+1
Information From 1H-NMR Spectrum
• Number of regions of peaks equals number of
unique hydrogen environments
• Coupling can be used to determine which sets
of hydrogens are adjacent to other sets.
• Integrations can tell about the relative number
of hydrogens in each environment.
• Location of peaks can indicate adjacency to
Information From 13C-NMR Spectra
• Only single peaks observed (no coupling).
• No integrations possible.
• Carbon spectra interpreted strictly on the
number of peaks and their respective locations.