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

Electron transfer reaction between [Fe(bipy)(3)](2+) and [Co(CN)(5)N-3](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/k(w), in the range 1.00k/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.