NMR satellites as a probe for chemical investigations

Satellite lines in nmr spectra have, since their discovery, served conspicuously for the study of molecular structure and chemical bonding. They can also be used for the determination of abundance ratios of isotopes; a comparison of the intensities of '3C—H satellite lines with that of the central line ('2C—H) gives the isotope ratio of '3C. This method is important in that it opens a way to determine the isotope abundance ratio in an individual functional group.1 Another application makes use of the difference in the spin—lattice relaxation times of the satellite and central lines. This difference reflects the relaxation of '3C spins and should give an insight into the 13C nuclear spin relaxation mechanisms.