The effect of components of the Ru (NH3) 6Cl3/Ru (NH3) 6Cl2 redox-pair on the dynamics of octanethiol monolayer formation on gold from aqueous thiol-containing solutions in 0. 1 M NaClO4 is studied by cyclic voltammetry. In this work, the method for assessing the adsorption activity of the components of the Ru (NH3) 63+/2+ redox-pair by the octanethiol dense monolayers on gold formation time was used. The introduction of the redox pair components into a thiol-containing solution is shown to lead to an increase in the formation time of octanethiol-monolayer insulating films and to the less stable monolayers’ formation. The inhibitory effect of hexaamineruthenium (II) / (III) ions decreased with increasing of octanethiol concentration in the solution. A difference in the adsorption activity of the ions composing the Ru (NH3) 63+/2+ redox-pair on gold in the presence of octanethiol is found: Ru (NH3) 63+ ions are better adsorbed than Ru (NH3) 62+ ones. A comparative assessment of the adsorption activity of two redox-pairs—Ru (NH3) 63+/2+ and Fe (CN) ₆^{{{3 - / {{3 - {4 - }}. -0em} 4 - }}} —is performed. It was shown that a typical redox pair Ru (NH3) 63+/2+, in contrast to the redox pair Fe (CN) ₆^{{{3 - / {{3 - {4 - }}. -0em} 4 - }}}, can be considered a test one, since the ions of this system are weakly adsorbed on the gold surface and make but insignificant impact on the thiol monolayer self-assembling process. The octanethiol and the hexaamineruthenium (II) / (III) and ferro-ferricyanide ions can be ranged, according to their adsorption activity on the gold electrode, as follows: octanethiol > Fe (CN) 63– ≈ Fe (CN) 64– Ru (NH3) 63+ > Ru (NH3) 62+.
S. N. Ovchinnikova (2025) studied this question.