Physicochemical insight of phosphonium-based ionic liquid with carbocyclic sugar-based inositol derivative

Abstract

Ionic liquids (ILs) are widely utilized as solubilizers, transporters, and agents for enhancing the efficacy of various components. In this study, the phosphonium-based ionic liquid (PIL) trihexyltetradecylphosphonium bis(2,4,4-trimethylpentyl)phosphinate ([P666(14)][TMPP]) was investigated for its synergic interaction with synthesized carbocyclic sugar-based inositol derivative 4-O-Tosyl-6-O-benzyl-myo-inositol-1,3,5-orthoformate (referred to as the tosyl derivative). These interactions were explored using a range of techniques including FTIR spectroscopy, dynamic light scattering (DLS), surface tension, conductivity, colorimetry, and viscometry at 299.0 ± 0.5 K temperature. Key parameters in physicochemical insight, such as the zeta potential, particle size distribution, critical micelle concentrations (CMC) and various thermodynamic parameters (Δ_G^°_ads, Δ_G^°_trans, ∆G^s_min, Δ_G^°_m, Δ_G^°_m,tail) and interfacial parameters (Г_max, A_min, π_CMC, pC₂₀, γ_CMC) were calculated. A significant reduction in CMC values of the PIL was observed with increasing concentrations (mM) of the tosyl derivative. The findings of the interfacial parameters indicated that when the concentration of tosyl derivative increased, the values of A_min, π_CMC, and pC₂₀ enhanced while the values of γ_CMC, Γ_max, and CPP undergo reduction. Further, conductometric and colorimetric studies give similar results for CMC value. The higher negative values of Δ_G^°_m and Δ_G^°_ads have been shown the micellization and adsorption properties became more spontaneous. The rheological characteristics of PIL, such as reducing, intrinsic, and relative viscosities, are more significantly impacted by higher concentrations of the tosyl derivative. The FTIR spectral response confirmed shifts in different stretching and bending modes indicating strong intermolecular interactions. DLS data further indicated that the polar nature of the tosyl derivative promotes the formation of significantly larger micelles in the PIL–tosyl derivative system (particularly at 2.0 mM) compared to the pure due to the tosyl derivative showing co-solvent character. These findings suggest potential applications for such synergistic systems in household products, pharmaceutical sciences, cosmetics, and drug delivery.