Quenching of the luminescenceof the tris(2,2'-bipyridine) complexes of ruthenium(II) and osmium(II). Kinetic considerations and photogalvanic effects
The quenching of the charge-transfer excited states of Ru(bpy)/sub 3//sup 2 +/ and Os(bpy)/sub 3//sup 2 +/ by O/sub 2/, Fe/sup 3 +/, Co(phen)/sub 3//sup 3 +/, Ry(NH/sub 3/)/sub 6//sup 3 +/, Os(bpy)/sub 3//sup 3 +/, and Fe(CN)/sub 6//sup 3 +/ has been studied by a spectrofluorometric method. The lifetime of the emitting state of the osmium (II) complex and the rate of its reaction with Ru(NH/sub 3/)/sub 6//sup 3 +/ were measured by a single-photon counting technique. A value of -0.96 V was estimated for the reduction potential of the Os(bpy)/sub 3//sup 3 +/ parallel *Os(bpy)/sub 3//sup 2 +/ couple. Emission intensity measurements were used to determine the steady-state concentrations of the Fe/sup 2 +/ and Ru(bpy)/sub 3//sup 3 +/ formed in the reaction of Fe/sup 3 +/ with the emitting state of Ru(bpy)/sub 3//sup 2 +/. The steady-state concentrations of the electron-transfer products increase in the order HCl < H/sub 2/SO/sub 4/ < HClO/sub 4/ approx. CF/sub 3/SO/sub 3/H and in 0.5 M HClO/sub 4/ amount to about 25 percent of the initial Ru(bpy)/sub 3//sup 2 +/ concentration under the conditions used. The Ru(bpy)/sub 3//sup 2 +/-Fe/sup 3 +/ system exhibits a large photogalvanic effect. The mechanisms of the reactions are discussed and general equations describing the steady-state characteristics of these systems are derived. (auth)
- Research Organization:
- Brookhaven National Lab., Upton, NY
- OSTI ID:
- 7197163
- Journal Information:
- J. Phys. Chem.; (United States), Journal Name: J. Phys. Chem.; (United States) Vol. 80:2; ISSN JPCHA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400500* -- Photochemistry
CATIONS
CHARGED PARTICLES
COBALT COMPLEXES
COMPLEXES
CRYOGENIC FLUIDS
ELECTRON TRANSFER
ELEMENTS
EMISSION SPECTROSCOPY
FLUIDS
FLUORESCENCE SPECTROSCOPY
HEAT TREATMENTS
IONS
IRON COMPLEXES
IRON COMPOUNDS
LUMINESCENCE
NONMETALS
OSMIUM COMPLEXES
OXYGEN
QUENCHING
RUTHENIUM COMPLEXES
SPECTROSCOPY
TRANSITION ELEMENT COMPLEXES
TRANSITION ELEMENT COMPOUNDS