Three Bis-BODIPY Analogous Diruthenium Redox Series: Characterization and Electronic Structure Analysis.

: The dianion derived from (2 Z ,6 Z )-3,7-diphenyl-N2,N6-di(pyridin-2-yl)pyrrolo[2,3- f ]indole-2,6(1H,5H)-diimine (H 2 BL), a modified BODIPY ligand precursor, is shown to be capable of bridging two metal complex fragments RuL 2 , 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 ](ClO 4 ) 2 ([ 3 ](ClO 4 ) 2 ) and [Ru(pap) 2 Ru(µ-BL)Ru(pap) 2 ](ClO 4 ) 2 ([ 4 ](ClO 4 ) 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 3 2+ and 4 2+ contain ruthenium(II) and get reduced or oxidized mainly at the dianionic bridge ( 3 2+ ) or are reduced at the ancillary ligands pap ( 4 2+ ).