A SERS (surface-enhanced Raman scattering) study of the binuclear ion complex [Fe2BPE(CN)(10)](6-) (BPE = trans-1,2-bis (4-pyridyl) ethylene) adsorbed on a silver electrode in different solvents is presented. The cycle voltammogram of the complex, in the region of the Fe-II/Fe-III redox process, shows two oxidation and two reduction waves separated by 0.15 V, indicating that the two iron centers are electronically coupled via the bridging ligand. The SERS measurements have shown that both SERS intensity and frequency position of the bridging ligand modes present strong dependence on the applied potential. Remarkable changes in the structure of the ligand are observed for applied potentials more negative than -1.0 V, where the complex is reduced. The C=C ethylenic inter ring stretching mode shifts from 1637 to 1555 cm(-1), indicating a decrease in this bond order for the reduced molecule. The chemical interaction of the complex with the silver surface also involves one or more CN ligands as evidenced by an upward frequency shift of the CN stretching mode in the adsorbed complex. Upon reduction, the V(CN) frequency shifts to lower energies, indicating that the electron transferred in the faradaic process is delocalized over the complex. On the basis of the SERS excitation profiles and their dependence on the exciting radiation, two potential modulated photon assisted charge-transfer processes have been characterized: an adsorbate to metal (HOMO(CN) --> Ag) and a metal to adsorbate (Ag --> LUMO(BPE)), responsible for the enhancement of the v(CN) and BPE modes, respectively. Resonance between the energy of the exciting radiation and the metal/adsorbate charge-transfer transitions is achieved at different applied potentials for different solvents, thus indicating that the position of the energy levels of the adsorbed complex relative to the Fermi level (EF) changes according to the chemical nature of the solvent and the solvent/adsorbate interaction. Energy diagrams showing the relative positions of the donor and acceptor states of the surface complex formed by the binuclear complex and the silver electrode surface in different solvents have also been proposed.