Influence of the mixed micelles on the electron transfer reaction [Co(NH3)5Cl]2+ + [Fe(CN)6]4−

Electron transfer reaction between chloropentaamminecobalt (III) and hexacyanoferrate (II) has been studied in the mixed surfactant aqueous solutions of sodium dodecyl sulfate (SDS) and octylphenol (ethylene oxide)9.5 ether (TX-100). The observed rate constants kobs have been determined for various micellar media with different compositions. A pseudophase model together with an outer-sphere electron transfer reaction mechanism has been used to analyze the experimental results to obtain the precursor complex formation equilibrium constant KIP, the electron transfer rate constant ket, and the pseudophase equilibrium constant K. The dependence of those parameters on the micellar concentration has been discussed.

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► Kinetics of [Fe(CN)6]4− + [CoCl(NH3)5]2+ in SDS/TX-100 mixed micelle media was studied.
► A pseudophase equilibrium model was used to interpret the experimental results.
► Pseudophase equilibrium constants and kinetic parameters were determined.
► Dependence of the kinetics on the micellar composition was investigated.