SYNTHESIS OF ADSORBABLE REDOX-ACTIVE OSMIUM THIOL MONOLAYERS AND THE EFFECTS OF THE WORKING ELECTRODE POTENTIAL DURING DEPOSITION

A new series of redox-active transition metal complexes of the type [Os(bpy)(2)Cl(Py-(CH2)(n)-SH)](PF6), with n = 4, 6, or 9, capable of forming adsorbed monolayers on gold, platinum and silver electrodes has been synthesized and the effect of the working electrode potential during deposition on the amount of material deposited onto the electrode surface has been studied using cyclic voltammetry. The amount of material deposited onto the working electrode at potentials negative of the potential of zero charge E(pzc) for a given metal electrode depended on the potential applied during deposition, but at potentials positive of E(pzc), the amount deposited was much smaller and virtually independent of the applied potential. The interaction most dominant in the adsorption process of these redox-active species appears to be electrostatic attraction and repulsion. In addition, this method provides for a facile way to determine E(pzc) for solid electrodes.