Preparation, Photophysical, Electrochemical, and Ion-Binding Properties of Ru(II) Polypyridyl Complexes Containing a Crown Ether Unit
| Autor: | Feixiang Cheng, Longhai Chen, Ning Tang, Jishu Chen, Fan Wang |
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| Rok vydání: | 2011 |
| Předmět: | |
| Zdroj: | Zeitschrift für Naturforschung B. 66:923-929 |
| ISSN: | 1865-7117 0932-0776 |
| Popis: | Two polypyridyl ligands, 4`-(4,5-diazafluoren-9-ylimino)benzo-15-crown-5 (L1) and 4` -(4,5-diazafluoren- 9-ylimino)benzo-12-crown-4 (L2), and their Ru(II) complexes [(bpy)2RuL1](PF6)2 and [(bpy)2RuL2](PF6)2, respectively, have been synthesized and characterized. The two complexes display metal-to-ligand charge transfer absorptions at around 444 nm in CH3CN solution at r. t. and emission at around 573 nm in an EtOH-MeOH (4 : 1, v/v) glassy matrix at 77 K. Electrochemical studies of the complexes show one Ru(II)-centered oxidation at around 1.33 V and three ligandcentered reductions. The binding ability of the complexes with Na+ and Li+ has been investigated by UV/Vis absorption and emission spectroscopy and electrochemical titrations. Addition of Na+ and Li+ to solutions of the complexes results in a progressive quenching of the emission, a hyperchromic effect of the UV/Vis absorption, and a progressive cathodal shift of the Ru(II)-centered E1/2 potential. The stability constants for the stoichiometric 1 : 1 ratio of the complexes and the cations have been obtained by UV/Vis absorption titration. |
| Databáze: | OpenAIRE |
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