An insight into the redox activity of Ru and Os complexes of the N,N′-bis(2-pyridyl)benzene-1,2-diamine ligand: Structural, electrochemical and electronic structure analysis by density functional theory calculations

The synthesis of Ru and Os complexes of the ligand, N,N′-bis(2-pyridyl)benzene-1,2-diamine namely, [Ru^III(acac)₂(Py-bqdi)], (9), [Ru^II(Ph-trpy)(Py-bqdi)Cl], (10) and [Os^II(bpy)₂(Py-bqdi)](ClO₄), ([11]ClO₄) [where Py-bqdi = N,N′-dipyridyl-o-benzoquinonediimine, acac = 2,4-pentanedionate, Ph-trpy = 4′-phenyl-2,2′:6′,2″-terpyridine, bpy = 2,2′-bipyridine] is reported. The molecular structures of complexes 9-[11]ClO₄ are authenticated by single crystal X-ray diffraction studies. The electronic structural properties of the complexes, in particular, the accessible oxidized/reduced forms of the complexes, are examined by using an array of analytical techniques (magnetic resonance, UV–Vis-NIR spectroscopy and electrochemistry). Comprehensive Density Functional Theory (DFT) calculations have also been carried out to provide additional support to the experimental work.