The Indigo Isomer Epindolidione as a Redox-Active Bridging Ligand for Diruthenium Complexes |
| |
| Authors: | Maya Kumari Sudip Kumar Bera Svenja Blickle Prof Dr Wolfgang Kaim Prof Dr Goutam Kumar Lahiri |
| |
| Institution: | 1. Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400076 India;2. Institut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring 55, 70550 Stuttgart, Germany |
| |
| Abstract: | Epindolidione (H2L), a heteroatom-modified analogue of tetracene and a structural isomer of indigo, forms dinuclear complexes with RuX2]2+, X=bpy (2,2′-bipyridine, 1 ]2+) or pap (2-phenylazopyridine, 2 ]2+), in its doubly deprotonated bridging form μ-L2−. The dications in compounds meso- 1 ](ClO4)2 and meso- 2 ](ClO4)2, X2Ru(μ-L)RuX2](ClO4)2, contain five-membered chelate rings N-C−C-O-RuII with π bridged metals at an intramolecular distance of 7.19 Å. Stepwise reversible oxidation and reduction is mainly ligand centered (oxidation: L2−; reduction: X), as deduced from EPR of one-electron oxidized and reduced intermediates and from UV/Vis/NIR spectroelectrochemistry, supported by TD-DFT calculation results. The results for 1 ](ClO4)2 and 2 ](ClO4)2 are qualitatively similar to the ones observed with the deprotonated indigo-bridged isomers with their six-membered chelate ring structures, confirming the suitability of both π systems for molecular electronics applications, low-energy absorptions, and multiple electron transfers. |
| |
| Keywords: | epindolidione redox non-innocence ruthenium spectroelectrochemistry structure |
|
|
