Dielectric and viscosity studies on the dipeptides of alanine and glycine

The dielectric properties of aqueous solutions of diglycine, dialanine, analyglycine and glycylalanine have been studied in their relaxation region. The deduced dipole moments are close to those expected from structural considerations, and the activation enthalpies suggest that a solute-water hydrogen bond is broken in the relaxation process. For most cases the results can be represented by a Debye-type dispersion with a single relaxation time, but for analylglycine at 0°c a distribution of relaxation times appears more probable. The viscosity measurements indicate that dielectric relaxation and the viscosity process are strongly related at a molecular level.