1. Three trinuclear Ru(II) complexes containing 4,5-diazafluorene and 2,2′-bipyridine: synthesis, absorption spectrum, luminescence, and redox behavior.
- Author
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Cheng, Feixiang, He, Chixian, Yao, Lifeng, Wang, Fan, and Tang, Ning
- Subjects
RUTHENIUM compounds ,OXIDATION-reduction reaction ,FLUORENE compounds ,COMPLEX compounds synthesis ,BIPYRIDINE ,ABSORPTION spectra ,LUMINESCENCE - Abstract
Three heterotopic ligands L1, L2, and L3have been prepared by the reaction of 4,4′-bis(bromomethyl)-2,2′-bipyridine with 4,5-diazafluoren-9-oxime, 9-(2-hydroxy)phenylimino-4,5-diazafluorene, and 9-(4-hydroxy)phenylimino-4,5-diazafluorene, respectively, in DMF. The three ligands consist of two 4,5-diazafluorene units and one 2,2′-bipyridine unit. Ru(II) complexes [{Ru(bpy)2}3(μ3-L1−3)](PF6)6(bpy = 2,2′-bipyridine) were prepared by refluxing Ru(bpy)2Cl2·2H2O and the ligands in 2-methoxyethanol. The three Ru(II) complexes display metal-to-ligand charge-transfer absorption at 445–450 nm and one Ru(II)-centered oxidation at 1.32 V in CH3CN solution at room temperature. Upon excitation into the metal-to-ligand charge-transfer band, the emission intensities of [{Ru(bpy)2}3(μ3-L2)]6+and [{Ru(bpy)2}3(μ3-L3)]6+are almost equal to that of [{Ru(bpy)2}3(μ3-L1)]6+in CH3CN solution at room temperature, but weaker than that of [{Ru(bpy)2}3(μ3-L1)]6+in EtOH–MeOH (4 : 1, v/v) glassy matrix at 77 K. [ABSTRACT FROM PUBLISHER]
- Published
- 2015
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