DFT Method Estimation of Standard Redox Potential of Metal Ions and Metal Complexes

The DFT method calculation was carried out to evaluate standard redox potential (SRP) for metal-to-metal cation and metal-to-metal complex systems. With the Born-Haber cycle, standard redox potential was composed of the cohesive energy, ionization energy, and solvation energy. The ligand exchange energy was added in case of metal complex. The solvent effects were incorporated by the self-consistent reaction field theory at the level of the polarized continuum model (PCM). At the highest level of calculations, the geometry optimization and harmonic frequency analysis were evaluated under the PCM. Utilizing experimental values of the cohesive energy of metals, the standard deviations between the calculated and experimental SRP values were 0.20-0.27 V depending on the calculation levels and basis sets used. For three Ag complexes with CN(-), S2O3(2-), and NH3 ligands, the discrepancy was within 0.3 V.