Three new pyrazine-bridged dimers of oxoacetatotriruthenium with an NO ligand are synthesized. These complexes show two types of stable mixed-valence states. The nu(NO) stretches for five oxidation states were obtained, and the intramolecular electron-transfer rate within the mixed-valence state is evaluated from the IR spectral line-shape simulation based on Bloch-type analysis, which is the first application of this method to a spectator ligand of NO.