Observations in Proton NMR Spectra of Long-Range Coupling Between Protons and Carbon-13 in Natural Abundance

Observations of long-range coupling were made with an NMR spectrometer with sample spinning frequencies of about 35 cps. Resulting satellite peaks located from 2.5 to 5 cps on either side of the principal peak center were found to have amplitudes approaching ten times the effective noise level. The satellite amplitude has the same order of magnitude as that of the foot of the main peak at the location of the satellite. The cause of the satellites was established by a study of a variety of compounds including sodium acetate labeled with C13 in a carboxyl group.