Effects of SDS, Triton X-100, and the Binary Mixture of Triton X-100/SDS Surfactants on the Electron Transfer Reaction Between Tris-2,2′-bipyridyl Iron(II) and Azidopentacyanocobaltate(III) Complexes

Abstract

Electron transfer reaction between [Fe(bipy)₃]²⁺ and [Co(CN)₅N₃]³⁻ has been studied in aqueous solutions of SDS, Triton X-100 and SDS/Triton X-100 mixtures. SDS inhibited the electron transfer reaction with inhibition factor k_ψ/k_w, in the range 1.00 ≤ k_ψ/k_w ≤ 2.53 while Triton X-100 showed no significant effect on the reaction. Binding parameters were obtained using Piszkiewicz model with cooperativity index n = 2.184 in the presence of SDS. Binary mixture of surfactants Triton X-100/SDS exhibit inhibition of the reaction at low concentrations of Triton X-100 with relative rate enhancement as the mixture becomes richer in Triton X-100. The results were explained in terms of strong electrostatic and/or hydrophobic interactions between the surfactants and the substrates.

Keywords:

• Azidopentacyanocobaltate(III)
• electron transfer
• inhibition
• surfactant mixture
• tris-2,2′-bipyridyliron(II)

Acknowledgments

The authors acknowledge the Organisation for the Prohibition of Chemical Weapons (OPCW) for sponsoring this research work carried out at the University of Botswana, Gaborone, Botswana.