Metalloporphyrin mixed-valence pi-cation radicals: solution stability and properties

The solution properties of the metalloporphyrin mixed-valence pi-cation radicals were studied using infrared spectroscopy and computer-aided computation of equilibrium constants. The results revealed that the stability of the metalloporphyrins arises from delocalization of a one-electron hole over two porphyrin rings. It was further demonstrated that the mixed-valence pi-cation radical complexes exhibit novel electronic absorption bands in the near-infrared spectrum which are not observed in either the neutral M(OEP) or the (M(OEP.))+ pi-cation radical derivatives.