Specific cation effect on quenching reactions of excited tris(α,α′-diimine) ruthenium(II) and chromium(III) complexes by cyanide complexes in aqueous solutions

Autor: Munetaka Iwamura, Takuhiro Otsuka, Youkoh Kaizu
Rok vydání: 2002
Předmět:
Zdroj: Inorganica Chimica Acta. 333:57-62
ISSN: 0020-1693
DOI: 10.1016/s0020-1693(02)00756-9
Popis: Specific salt effects were studied on the quenching reaction of excited [Ru(NN) 3 ] 2+ (NN=2,2′-bipyridine(bpy), 1,10-phenanthrorine(phen)) and [Cr(bpy) 3 ] 3+ by [Cr(CN) 6 ] 3− , [Fe(CN) 6 ] 3− and [Ni(CN) 4 ] 2− in aqueous solutions as a function of alkali metal ions which were added for adjustment of ionic strength. The quenching rate constants in [Ru(NN) 3 ] 2+ –[Cr(CN) 6 ] 3− and [Cr(bpy) 3 ] 3+ –[Cr(CN) 6 ] 3− systems are changed by the cations as Li + >Na + >K + ≈Rb + ≈Cs + . On the other hand, the rate constants in [Ru(NN) 3 ] 2+ –[Fe(CN) 6 ] 3− and [Ru(NN) 3 ] 2+ –[Ni(CN) 4 ] 2− systems, which are diffusion-controlled reactions, are not varied by the alkali metal cations. The obtained order (Li + >Na + >K + ≈Rb + ≈Cs + ) of the quenching rate constant is quite different from salt effects, Li + + + + + , which have been obtained in the electron transfer reactions between complex anions.
Databáze: OpenAIRE
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