Interference No. 103,675
differs from that of a proton oriented in the opposite
direction.
The protons are then exposed within
the NMR instrument to a radio frequency excitation that can
change their orientation. This excitation gives rise to a
signal from each proton. After a Fourier transform treatment
carried out by the NMR instrument, a spectrum showing all
the signals is produced.
In the spectrum, the signals
corresponding to each proton experience a displacement
generally to the left of an axis referenced at * 0 ppm. This
displacement (*), commonly referred to as chemical shift
value in ppm, is largely determined by the nature of the
chemical group(s) to which the atom, in general a carbon,
bearing the proton in question, is bonded. ...
An NMR spectrum is
sometimes referred to as the fingerprint of a compound. For
any compound containing protons, the chemical shifts of the
different protons are largely determined by the neighboring
atoms and are considered as characteristic. Thus, NMR can be
used to verify or disprove a proposed structure of a
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