SELF-DIFFUSION AND C-13 RELAXATION OF SELF-ASSOCIATED 1,10-PHENANTHROLINE

Self-diffusion coefficients as well as C-13 relaxation times and, for comparison, H-1 chemical shifts of 1,10-phenanthroline hydrochloride in D2O were measured to describe the formation of molecular stacks. The description of the concentration dependencies of the average self-diffusion coefficients and relaxation rates is based on a nonlinear least-squares fit of the equilibrium constants derived from the sequential-equal-K (SEK) and attenuated-K (AK) models. The self-diffusion coefficients and the relaxation rates of the individual stacks necessary for the calculation of the averages were evaluated by using hydrodynamic models adopted for this special approach. While the SEK and AK models are equally well suited for interpretation of the self-diffusion measurements, the AK model is at least slightly favorable for the description of the relaxation measurements.