Robust redox transformation of dithionate ion with a coordinated molybdenum complex via surfactant activation: micellar, thermodynamic, and kinetic study

The detail of sulphur oxyanions oxidation with coordination complexes in a surfactant environment has been sparingly tapped. Hence, the redox transformation of the dithionate ion (S₂O₆²⁻) with coordinated molybdenum (CM) complex and surfactant involvement is studied with the spectrophotometric method, following a pseudo-concentration approach. The result highlights the inclusion of proton initiation, ion catalysis, and the positive primary salt effect, which facilitate the redox transformation by enhancing the rate. The sulphate–proton-coupled radical generation acts the essential factors in S₂O₆²⁻ oxidation, with the exclusion of stable intermediate species formation as pointed by Michaelis–Menten-type plot and spectroscopic evidence. The contribution of thermodynamic parameters (∆H^ǂ, ∆G^ǂ, and ∆S^ǂ) is instrumental in the redox process as the system is energy-driven and ordered, leading to the sulphur dioxide product. The inclusion of a surfactant, sodium dodecyl sulphate (SDS), gives a hydrophobic support to the redox progress at the Gouy–Chapman layer of the micelles, as strengthened by the cooperativity and binding constant of the Raghavan and Srinivasan’s model.

Graphical abstract