Synthesis, photophysical, and electrochemical properties of three novel Ru(II) polypyridyl complexes containing dibenzo-18-crown-6

Three polypyridyl bridging ligands cis-di(4,5-diazafluoren-9-ylimino)dibenzo-18-crown-6 (BL1), trans-di(4,5-diazafluoren-9-ylimino)dibenzo-18-crown-6 (BL2), and 1,4,7,10,13,16-hexaoxacycloctadecyl[2,3:11,12]bis-dipyrido[3,2-a:2′3′-c]phenazine (BL3), and corresponding dinuclear Ru(II) complexes [(bpy)2RuBL1−3Ru(bpy)2](PF6)4 (1, 2, and 3) have been synthesized. Cyclic voltammetry of the complexes are consistent with one Ru(II)-centered oxidation and three ligand-centered reductions. Photophysical behaviors are investigated by UV–Vis absorption and fluorescence spectrometry. The three complexes show metal-to-ligand charge transfer absorption at 445–453 nm and emission at 571–593 nm.