The dianion derived from (2Z,6Z)-3,7-diphenyl-N2,N6-di(pyridin-2-yl)pyrrolo[2,3-f]indole-2,6(1H,5H)-diimine (H2 BL), a modified BODIPY ligand precursor, is shown to be capable of bridging two metal complex fragments RuL2 , L=2,4-pentanedionato (acac- ), 2,2'-bipyridine (bpy) or 2-phenylazopyridine (pap) in [Ru(acac)2 Ru(μ-BL)Ru(acac)2 ] (1/2), [Ru(bpy)2 Ru(μ-BL)Ru(bpy)2 ](ClO4 )2 ([3](ClO4 )2 ) and [Ru(pap)2 Ru(μ-BL)Ru(pap)2 ](ClO4 )2 ([4](ClO4 )2 ). The compounds, including a diastereoisomeric pair 1 (meso) and 2 (rac) were spectroscopically and structurally characterized. Reversible electron transfers as revealed by cyclic and differential pulse voltammetry allowed for an EPR and UV-vis-NIR spectroelectrochemical investigation of several neighboring charge states. Together with susceptibility measurements and TD-DFT calculations the assignment of oxidation states reveals that 1, 2 are diruthenium(III) species which can be oxidized or reduced by one electron whereas 32+ and 42+ contain ruthenium(II) and get reduced or oxidized mainly at the dianionic bridge (32+ ) or are reduced at the ancillary ligands pap (42+ ).
Keywords: Ruthenium; aza-BODIPY; redox non-innocence; spectroelectrochemistry; structure.
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