Ein- und zweikernige Bis(2,2′-bipyridyl)ruthenium-Komplexe mit N,O-Modelliganden für Dehydrogenase-Cofaktoren / Mono- and Binuclear Bis(2,2′-bipyridine)ruthenium Complexes with N,O-Ligands Modelling Dehydrogenase Cofactors

Coordination of substitutionally inert [Ru(bpy) fragments (bpy: 2,2′-bipyridine) to the a-iminoketone chelate ligands pyrazine-2-dimethylcarboxamide (4) and 4,7-phenanthroline-5,6-dione (5) yields the complexes [(N,O-4)Ru(bpy) , [(O,O′-5 )Ru(bpy) and {(N,O; N′,O′-5)[Ru(bpy) which exhibit a rich electrochemistry. The distinctly different electronic structures of the complexes are evident from the ESR behaviour of paramagnetic intermediates: N.O-coordinated complexes have the unpaired electron residing in the ligand n system upon reduction, albeit with g