Anomalous PMR spectra of cobalt(III) and rhodium(III) NN'-dialkyldithiocarbamates

A non-equivalence of α-methylene protons has been observed in the proton resonance spectra of cobalt(III) and rhodium(III) NN'-dialkyldithiocarbamates (where alkyl groups are ethyl, n-propyl and benzyl). The spectra are interpreted in terms of hindered rotation about the C---N bond. The barrier to rotation has been found to be 17.0 kcal/mole for the cobalt(III) diethyldithiocarbamate