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 kψ/kw, in the range 1.00 ≤ kψ/kw ≤ 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.