title: Metal-Metal Bridging Using the DPPP Dye System: Electronic Configurations within Multiple Redox Series.
abstract: Redox series [LnRu(μ-DPPP)RuLn]k, H2DPPP = 2,5-dihydro-3,6-di-2-pyridylpyrrolo(3,4-c)pyrrole-1,4-dione and L = 2,4-pentanedionato (acac-), 2,2'-bipyridine (bpy), and 2-phenylazopyridine (pap), have been studied by voltammetry (CV, DPV), EPR, and UV-vis-NIR spectroelectrochemistry, supported by TD-DFT calculations. Crystal structure analysis and1H NMR revealed oxidation states [(acac)2RuIII(μ-DPPP2-)RuIII(acac)2] and [(bpy)2RuII(μ-DPPP2-)RuII(bpy)2]2+for the corresponding precursors, isolated as rac diastereomers. Oxidation was observed to occur mainly at the bridging ligand (DPPP2-→ DPPP•-), whereas the site of reduction (DPPP, Ru, or L) depends on effects from the ancillary ligands L. The metal coordination of a derivative of the pigment forming 2,5-dihydro-pyrrolo(3,4-c)pyrrole-1,4-dione (DPP) dyes and the analysis of corresponding multistep redox series add to the previously recognized coordinative and electron transfer potential of dye molecules of the azo, indigo, anthraquinone, and formazanate type.
authors.affiliation: Department of Chemistry, Indian Institute of Technology Bombay , Powai, Mumbai 400076, India.
authors.forename: Arijit
authors.initials: A
authors.lastname: Singha Hazari
authors.affiliation: Department of Chemistry, Indian Institute of Technology Bombay , Powai, Mumbai 400076, India.
authors.forename: Abhishek
authors.initials: A
authors.lastname: Mandal
authors.affiliation: Institut für Anorganische Chemie, Universität Stuttgart , Pfaffenwaldring 55, D-70550 Stuttgart, Germany.
authors.forename: Katharina
authors.initials: K
authors.lastname: Beyer
authors.affiliation: Institut für Anorganische Chemie, Universität Stuttgart , Pfaffenwaldring 55, D-70550 Stuttgart, Germany.
authors.forename: Alexa
authors.initials: A
authors.lastname: Paretzki
authors.affiliation: Institut für Anorganische Chemie, Universität Stuttgart , Pfaffenwaldring 55, D-70550 Stuttgart, Germany.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Kaim
authors.affiliation: Department of Chemistry, Indian Institute of Technology Bombay , Powai, Mumbai 400076, India.
authors.forename: Goutam Kumar
authors.identifier: http://orcid.org/0000-0002-0199-6132
authors.initials: GK
authors.lastname: Lahiri