L1 /
7
CH1012
1H
& 13C NMR II
Nature of NMR absorptions
• Fortunately 1H nuclei
in different chemical environments
absorb energy at slightly different frequencies. 13C nuclei
do the same
downfield
or lowfield
or lowfield
upfield
or highfield shift
or highfield shift
• Hence we expect
to see different
NMR signals for
each different type
of 1H (or 13C)
nucleus in a
molecule.
to see different
NMR signals for
each different type
of 1H (or 13C)
nucleus in a
molecule.
• Frequency scale
in ppm ® chemical shift
