Mixed valence isomers

The infrared spectroscopic observation of mixed valence isomers, the two alternate charge distributions of a mixed valence complex, is reported. Asymmetry induced by the 2-methylpyrazine bridging ligand was used to energetically differentiate the two states, and isotopic labeling of CO was used to spectroscopically observe the two states. Infrared line shape analysis was used to determine rate constants for electron transfer of 6.5 x 1011 s-1 and equilibrium constants of 2.2 for the mixed valence isomers.