Micellization of Metallosurfactant N-Dodecyl/Hexadecyl/Octadecyl Salicylaldimine Cobalt(III) Complexes in Nonaqueous Media

Abstract

Abstract The critical micelle concentrations (CMC) of three metallosurfactant Schiff base cobalt(III) complexes of the type [Co(trien)(C19H30NO)]Cl2,[Co(trien) (C23H38NO)]Cl2 and [Co(trien)(C25H42NO)]Cl2, where trien = triethylenetetramine, have been studied in n-alcohol and in formamide at different temperatures by the electrical conductivity method. CMCs have also been measured as a function of percentage concentration of alcohol in the mixed solvents with formamide. Specific conductivity data (at 303–323 K) served for the evaluation of the temperature-dependent CMC and thermodynamic parameters such as the standard Gibbs energy changes (\(\Delta G^{\circ}_{\mathrm{mic}})\), enthalpy changes (\(\Delta H^{\circ}_{\mathrm{mic}})\), and entropy changes (\(\Delta S^{\circ}_{\mathrm{mic}})\) of micelle formation. It is suggested that addition of an alcohol leads to increased penetration of formamide into the micellar interface, the extent depending on the alcohol’s chain length. The results have been discussed in terms of the solvophobic interaction, dielectric constant of the medium, the chain length of the alcohol, and the surfactant in the solvent mixture.