Strong and weak coupling in mixed-valence complexes bridged by 4,4′-azo-di(phenylcyanamido)

Intervalence band properties and IR spectroelectrochemistry of the mixed-valence complexes [{Ru(tpy∗)(bpy)}2(μ-adpc)]3+ and trans,trans-[{Ru(tpy∗)(pc)}2(μ-adpc)]+ are consistent with delocalized and valence trapped mixed-valence properties respectively. Data support hole-transfer superexchange as the dominant mechanism for metal-metal coupling.