Kopplung zwischen Polypyridinruthenium(II)‐ und Methylviologen‐Einheiten in π‐konjugierten Hybridsystemen

Coupling between Polypyridineruthenium(II) and Methylviologen Moieties in n‐Conjugated Hybrid Systems Complexes between the novel 3,3′‐diazamethylviologen chelate ligands and the [Ru(bpy)2]2+ fragment were synthesized and characterized by cyclic voltammetry, electronic absorption spectroscopy, and electron spin resonance. Incorporation into a common π system results in strong electronic coupling between the 4,4′‐bipyridinium and the tris(α‐diimine) metal chelate functions with significantly altered spectroscopic properties. The isomeric complexes with 4,4′‐diquaternized 2,2′‐bipyrazine ligands exhibit smaller electronic coupling and irreversible second reduction to a non‐Kekule system which helps to understand the superior photosensitizing properties of 2,2′‐bipyrazine complexes