Photoionization of Ru(bpy)32+ ions in aqueous solutions containing sodium dodecyl sulfate.: Influence of ion binding

Sodium dodecyl sulfate (SDS) augments the yield of biphotonic ionization of tris-2,2'-bipyridyl ruthenium(II) ions (3.75 X 10(-5) mol dm(-3)) in aqueous solution at room temperature to different extents at two different concentration ranges: by a factor 4 at [SDS] just below the critical concentration for precipitation (4.5 X 10(-4) mol dm(-3)) and by a factor 1.4 at [SDS] above the critical micellar concentration (8 X 10(-3) mol dm(-3)). The augmentation of the photoionization yield is explained in terms of ion binding, i.e, electrostatic interaction between Ru(bpy)(3)(2+) ions and dodecyl sulfate ions which results in a partial charge neutralization with the consequence of a decrease in the ionization potential. (C) 1999 Elsevier Science B.V. All rights reserved.