Study of Binuclear Complexes with two [Ru II (bpy) 2 ] 2+ Moieties Coordinated by a Bridging Binucleating Ligand (L) Bearing two Bidentate Chelating Sites

Abstract

Three series, each of four sets, of binuclear ruthenium(II) complexes of the type [(bpy)₂Ru^II(L) Ru^II(bpy)₂](ClO₄)₂2H₂O; (L = binucleating ligand, bearing two 2-hydroxy-4-(n-alkoxy)benzaldimino moieties bound to (CH₂)₂, (CH₂)₃ or 1, 4-disubstitutedbenzene bridge and, bpy = 2,2′-bipyridine), have been synthesised and characterised. The complexes are diamagnetic and comparative ¹H NMR spectral studies of the complexes and the ligands establish the binuclear composition of the complexes. All the complexes display four metal-to-ligand charge transfer transitions in the visible region of the electronic spectra. In acetonitrile the complexes show one reversible oxidation process in the potential range 0.57–0.60 V, due to the oxidation of the ruthenium(II) centres to ruthenium(III). The complexes are non-luminescent at room temperature and are catalytically inactive to oxygenation reactions.