Tuning interaction in dinuclear ruthenium complexes: HOMO versus LUMO mediated superexchange through azole and azine bridges

In this review the interaction between metal centers in dinuclear complexes based on azole and azine containing bridging ligands is reviewed. The focus of the review is on the manner in which the interaction pathway can be manipulated by variations in the nature of both the direct bridging unit and the peripheral substituents. Ruthenium polypyridyl type complexes will form the basis of this overview with particular attention paid to the electrochemical and spectroelectrochemical investigation of mixed valence compounds.