Abstract
Polynuclear metal complexes of which redox sites are connected with π-conjugated ligands take a number of mixed valence states. They exhibit several redox potentials owing to interaction between redox centers through the π-conjugated bridges. Questions arise about the definition of the interaction, a relation between the number of nuclei and the number of redox potentials, and a relationship between redox potentials and geometry of the complexes. This paper answers these questions thermodynamically as well as quantum mechanically. The interaction energy in this paper is defined as a pair energy between a reduced and an oxidized sites. Even this simplest definition generates complicated redox behaviors because of formation of various isomers when the number of metal centers increases.
