A donor–chromophore complex containing the polyazine bridging ligand 2,3-bis(2-pyridyl)pyrazine

The complex [(PTZpbpy)2Ru(dpp)](PF6)2 coupling a phenothiazine derived electron donor to a ruthenium complex with a polyazine bridging ligand dpp (PTZpbpy = 4-methyl-4′-(4-(N-phenothiazinato)pentyl)-2,2′-bipyridine, dpp = 2,3-bis(2-pyridyl)pyrazine) has been synthesized and the redox, spectroscopic, and excited state properties elucidated. In the coupled electron donor system, the emission intensity from the Ru(dπ) → dpp(π∗) 3MLCT state is quenched by 94% of that of the analogous system [(bpy)2Ru(dpp)](PF6)2 (bpy = 2,2′-bipyridine) which lacks a coupled electron donor. Coupling a donor–chromophore unit to a bridging ligand will allow the expansion of the molecular architecture to form complex molecular assemblies which contain covalently attached electron donors.

The electrochemical and photochemical properties of the complex [(PTZpbpy)2Ru(dpp)](PF6)2 (PTZpbpy = 4-methyl-4′-(4-(N-phenothiazinato)pentyl)-2,2′-bipyridine, dpp = 2,3-bis(2-pyridyl)pyrazine) which couples a donor–chromophore unit to a bridging ligand is reported. This complex displays weak emission from the Ru(dπ) → dpp(π∗) 3MLCT state compared to the analogous system [(bpy)2Ru(dpp)](PF6)2 (bpy = 2,2′-bipyridine) indicative of intramolecular electron transfer from the coupled electron donor. The title complex will allow the construction and study of complex photochemical molecular devices with coupled electron donors.Figure optionsDownload as PowerPoint slide