Synthesis, photophysical, and electrochemical properties of two novel trinuclear Ru(II) polypyridyl complexes

Two polypyridyl ligands 2,2′,2″-tris((4,5-diazafluoren-9-yliminoxy)ethyl)amine (L1) and 1,3,5-tris((4,5-diazafluoren-9-yliminoxy)methyl))-2,4,6-trimethylbenzene (L2), and corresponding trinuclear Ru(II) complexes [(bpy)6L1−2(RuII)3](PF6)6 (Ru-L1, Ru-L2) have been synthesized. Cyclic voltammetry of the complexes are consistent with one Ru(II)-centered oxidation at 1.32 V and four ligand-centered reductions. Photophysical behaviors are investigated by UV–Vis absorption and fluorescence spectrometry. The two complexes show metal-to-ligand charge transfer absorption at 440 nm and emission at around 580 nm.