Interactions between the Tris(1,10-phenanthroline)iron(II) Cation and Anionic Surfactants: Diffusion and Conductance Studies

Tracer diffusion coefficients for the [Fe(phen)3]2+ cation (phen=1,10-phenanthroline) have been measured in aqueous solutions of sodium 1-hexane-, 1-octane-, 1-decane-, and 1-dodecanesulfonate (NaDSO) in concentration ranges below the critical micelle concentrations of the surfactants and at 298.2 K. The diffusion coefficient decreases with an increase in the concentration of the surfactants. At a fixed concentration, the diffusion coefficient decreases with an increase in the carbon number of the surfactants. The results are compared with our previous results in sodium dodecyl sulfate (NaDS) solutions. The conductivities of the NaDSO and NaDS solutions were also measured at 298.2 K in the presence and absence of [Fe(phen)3]SO4. In the presence of [Fe(phen)3]SO4, the molar conductivities of the surfactants first decrease, then increase, and finally decrease again with an increase in the concentration of the surfactants.