The nature of iodine-amine solutions

When I2 is dissolved in pure amine, it is quantitatively reduced to iodide, the oxidation product being a symmetrical substituted hydrazine. Tertiary-butylamine reacts much more slowly than the other butylisomers, however, and the amine-iodine adduct can be isolated in that case. The observed proton magnetic resonance spectra show a single NH peak as a result of exchange averaging between at least twelve species. This peak shifts far downfield as more iodine is added, chiefly because of the contribution from protonated amine. We have determined equilibrium constants for a number of the proton exchange reactions and NH proton chemical shifts for some of the species present. Several other equilibrium constants and chemical shifts could not be reliably determined.