Thermodynamic properties of vanadyl (N,N′-salicylideneethylendiamine) Schiff base complex in ionic liquid + N,N-dimethylacetamide solutions

Effect of an ionic liquid, 1-propyl-3-methylimidazolium bromide ([PMIm]Br) on the thermodynamic and thermophysical properties of a transition metal Schiff base complex, vanadyl (N,N′-salicylideneethylendiamine), VO(salen) in N,N-dimethylacetamide mixtures have been investigated at 298.15 K. The standard partial molar volumes, Vϕ0, transfer partial molar volumes, ΔtVϕ0 have been calculated using the measured densities of the mixtures. The obtained viscosity B-coefficients and activation free energy of solvent and solute was used to interpret of structure breaking tendency of ionic liquid. The calculated limiting molar conductivities, Λ0, and ion association constants, KA, of ionic liquid obtained from low concentration chemical model of conductance equation have been used to confirm the conclusions obtained from the volumetric and viscometric properties. The results were discussed in terms of various solute–solvent interactions.

► Thermodynamic properties of VO(salen) + ionic liquid + DMA mixtures were investigated.
► The ion–nonpolar and nonpolar–nonpolar interactions were dominant in mixtures.
► The ionic liquid has structure breaking tendency on the studied mixtures.