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Photophysics of Ion Clusters Formed between [Ru(bpy) 3 ] 2+ and the Polyoxotungstate Anion [S 2 W 18 O 62 ] 4-

2004; American Chemical Society; Volume: 108; Issue: 36 Linguagem: Inglês

10.1021/jp0482464

1520-5215

Michael K. Seery, Liz Guerin, Robert J. Forster, Etienne Gicquel, Victoria M. Hultgren, Alan M. Bond, Anthony G. Wedd, Tia E. Keyes,

Advanced Nanomaterials in Catalysis

The interactions between [Ru(bpy)3]2+ and the polyoxotungstate anion [S2W18O62]4- in acetonitrile solution were investigated using a combination of photophysics and optical and Raman spectroscopies. The presence of ion clusters of {[Ru(bpy)3][S2W18O62]}2- (K2 = 7.7 × 105) and [Ru(bpy)3]2[S2W18O62] (K1 = 1.0 × 106 mol-2 dm-6) are inferred. The 2:1 complex is weakly luminescent, with a lifetime at room temperature of 20 ns under aerobic conditions. Difference electronic absorption, excitation, and resonance Raman spectroscopies indicate that the tungstate anion participates in this transition. Under conditions where [Ru(bpy)3]2+ alone is photolabile, the ion clusters are photostable, with no photodecomposition or photoinduced ligand exchange reactions evident in acetonitrile. This characteristic is examined employing temperature-dependent luminescent studies which demonstrate that the observed activation energy and preexponential factor are considerably different from those of free [Ru(bpy)3]2+and are characteristic of a photostable polypyridylruthenium complex.