Structural, electrochemical and photophysical properties of an exocyclic di-ruthenium complex and its application as a photosensitizer. Issue 23 (24th May 2016)

• Record Type: Journal Article
• Authors: Salpage, Sahan R.; Paul, Avishek; Som, Bozumeh; Banerjee, Tanmay; Hanson, Kenneth; Smith, Mark D.; Vannucci, Aaron K.; Shimizu, Linda S.
• Is Part Of: Dalton transactions. Volume 45:Issue 23(2016)
• Page Start: 9601
• Page End: 9607
• Publication Date: 2016-05-24
• Subjects: Chemistry, Inorganic -- Periodicals; Chemistry, Physical and theoretical -- Periodicals; Chemistry, Inorganic -- Periodicals; 546.05
• DOI: 10.1039/c6dt01377e
• Languages: English
• ISSNs: 1477-9226

Abstract

Abstract : Structural, photophysical, and electrochemical characterization of a bridged exo -diruthenium compound [(bpy)2 RuLRu(bpy)2 ]Cl4 ·6H2 O and use as a recyclable SET catalyst. Abstract : The reaction of cis -bis(2, 2′-bipyridine)dichlororuthenium(ii ) hydrate with a conformationally mobile bipyridyl macrocycle afforded [(bpy)2 Ru(μ-L)Ru(bpy)2 ]Cl4 ·6H2 O, a bridged di-Ru complex. Single crystal X-ray diffraction showed the macrocyclic ligand adopting a bowl-like structure with the exo -coordinated Ru(ii ) centers separated by 7.29 Å. Photophysical characterization showed that the complex absorbs in the visible region ( λ max = 451 nm) with an emission maximum at 610 nm ( τ = 706 ns, Φ PL = 0.021). Electrochemical studies indicate the di-Ru complex undergoes three one-electron reversible reductions and a reversible one-electron oxidation process. This electrochemical reversibility is a key characteristic for its use as an electron transfer agents. The complex was evaluated as a photocatalyst for the electronically mismatched Diels–Alder reaction of isoprene and trans -anethole using visible light. It afforded the expected product in good conversion (69%) and selectivity (dr > 10 : 1) at low loadings (0.5–5.0 mol%) and the sensitizer/catalyst was readily recycled. These results suggest that the bipyridyl macrocycle could be widely applied as a bridging ligand for the generation of chromophore-catalyst assemblies.