Synthesis and characterization of dinuclear complexes of 3,3′,4,4′-tetraminobiphenyl with tetramminoruthenium and bis(bipyridine)ruthenium residues and their two- and four-electron oxidized products including a ZINDO study of orbital mixing as a function of ligand oxidation state †

Abstract

This paper reports the synthesis, characterisation and reactivity of new complexes of ruthenium, the symmetric dinuclear complex of ruthenium tetrammine [(Ru(NH3)4)2(catH4·catH4)](PF6)4 and the asymmetric dinuclear complex of ruthenium bis(bipyridine) and ruthenium tetrammine [Ru(NH3)4(catH4·catH4)Ru(bpy)2](PF6)4 where (catH4·catH4) represents the bridging ligand 3,3′,4,4′-tetraminobiphenyl. These complexes can be oxidized to the two-electron oxidized ligand mixed valence (qH2·catH4) species and the four-electron oxidized ligand (qH2·qH2) species. Further oxidation yields a range of Ru(III) species. These complexes were studied by proton NMR, UV–VIS spectra, cyclic voltammetry and ZINDO/1 and ZINDO/S calculations.