Reactions of a Triruthenium Complex Self-assembled on Au

After holding the potential at +0.8 V for 20 min, the redox peaks disappear and a new set of redox peaks appear at -0.1 V as shown by the dashed trace in Fig. 8.13a. The corresponding SEIRAS spectrum (Fig. 8.13a, dashed trace) clearly shows the dissociation of the CO hgand. The electron backdonation from the Ru to CO weakens the CO-Ru bonding and results in the CO dissociation. The solvent molecule is believed to coordinate to the Ru center (solvent-SAM), and the redox peaks at -0.1 V are ascribed to the one-electron transfer between [(Ru -solvent) Ru Ru V° and [(Ru -solvent) Ru Ru V - 

As shown in Figs. 13b and b, no changes occur in either the CV or IR spectrum of the solvent-SAM after contact with the CO-saturated solution for 1 h at the rest potential (ca. +0.3 V). However, when the potential is changed to -0.3 V where the solvent-SAM is reduced to [(Ru -solvent)Ru Ru ]°, both the CV (Fig. 8.13c) and the IR spectrum (Fig. 8.13c ) recover to the original states (soHd lines in Fig. 8.13a and a ), indicating that CO replaces the solvent hgand and rebinds to the central Ru ion under potential control. 

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