Comparison of Metal−Metal Electronic Interactions in an Isomeric Pair of Dinuclear Ruthenium Complexes with Different Bridging Pathways: Effective Hole Transfer through a Bis-phenolate Bridge

Complexes A and B are isomeric but have different bridging pathways linking the two Ru(II) centers. Electrochemical and UV/vis/NIR spectroelectrochemical measurements both show that the metal−metal electronic coupling is considerably stronger in B than in A despite the greater metal−metal separation, because the oxidized Ru(II)/Ru(III) mixed-valence state can be delocalized by hole transfer across the (oxidizable) bis-phenolate bridge.