Abstract
Coordination of substitutionally inert Ru(bpy)22+ fragments (bpy = 2,2'-bipyridine) to the a-iminoketone chelate ligands pyrazine-2-dimethylcarboxamide (L) and 4,7-phenanthroline-5,6-dione (HL') yields Ru(bpy)2(L-N,O)2+, Ru(bpy)2(L'-O,O')+, and ((L'-N,O;N',O')Ru(bpy)224+ which exhibit a rich electrochem. The distinctly different electronic structures of the complexes are evident from the ESR behavior of paramagnetic intermediates: N,O-coordinated complexes have the unpaired electron residing in the ligand p system upon redn., albeit with g \textless2 for the complex of L but with g \textgreater2 for the binuclear complex of HL'. The paramagnetic O,O'-coordinated mononuclear complex with (L') has its redox potentials shifted pos. relative to that of the binuclear system. These results are particularly noteworthy because L and HL' can be regarded as model compds. for the flavin and methoxatin dehydrogenase cofactors. on SciFinder(R)
Users
Please
log in to take part in the discussion (add own reviews or comments).