Kinetics and mechanism of the quenching of the emission of substituted polypyridineruthenium(II) complexes. Reactions of RuL/sub 3//sup +/, *RuL/sub 3//sup 2 +/, and RuL/sub 3//sup 3 +/ with the copper(I)-copper(II) couple. [L: bipyridine or phenanthroline derivative; laser radiation, pulsed irradiation studies also include Os(II)/sub 3//sup 2 +/ complexes]
The series of complexes RuL/sub 3//sup 2 +/, where L is a bipyridine or phenanthroline derivative, has been used to study the mechanism of the quenching of the luminescent excited state of RuL/sub 3//sup 2 +/ by copper(II) ions in aqueous solution. The quenching rate constants were obtained from emission intensity measurements. A pulsed dye laser was used to generate the electron-transfer products RuL/sub 3//sup 3 +/ and copper(I) and the rate constants for the reactions of these products to re-form RuL/sub 3//sup 2 +/ and copper(II) were measured. Rate constants for the quenching of some OsL/sub 3//sup 2 +/ complexes were also determined. The rate constants for the reaction of copper(II) with RuL/sub 3//sup +/, generated by pulse radiolysis, were measured and compared with the rate constants for the reaction of copper(II) with *RuL/sub 3//sup 2 +/. On the basis of these results and spectroscopic considerations it is concluded that the quenching of *RuL/sub 3//sup 2 +/ by copper(II) proceeds by an electron-transfer mechanism. The free-energy dependence of the quenching reactions is smaller than expected for an electron-transfer mechanism and possible reasons for this behavior are discussed. The quantum yields for the formation of separated electron-transfer products are analyzed in terms of the electron-transfer rates within the primary cages and the rates of the thermal back reactions. 4 figures, 3 tables, 20 references.
- Research Organization:
- Brookhaven National Lab., Upton, NY
- OSTI ID:
- 6900988
- Journal Information:
- J. Am. Chem. Soc.; (United States), Vol. 100:8
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
COPPER COMPOUNDS
CHEMICAL REACTION KINETICS
OSMIUM COMPLEXES
RUTHENIUM COMPLEXES
AQUEOUS SOLUTIONS
CHEMICAL RADIATION EFFECTS
DYE LASERS
ELECTRON TRANSFER
ENERGY DEPENDENCE
FLUORESCENCE SPECTROSCOPY
FREE ENERGY
IONS
LASER RADIATION
PHOTOCHEMICAL REACTIONS
PULSED IRRADIATION
QUENCHING
RADIOLYSIS
CHARGED PARTICLES
CHEMICAL REACTIONS
CHEMISTRY
COMPLEXES
DECOMPOSITION
DISPERSIONS
ELECTROMAGNETIC RADIATION
EMISSION SPECTROSCOPY
ENERGY
HEAT TREATMENTS
IRRADIATION
KINETICS
LASERS
MIXTURES
PHYSICAL PROPERTIES
RADIATION CHEMISTRY
RADIATION EFFECTS
RADIATIONS
REACTION KINETICS
SOLUTIONS
SPECTROSCOPY
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPLEXES
TRANSITION ELEMENT COMPOUNDS
400201* - Chemical & Physicochemical Properties
400500 - Photochemistry
400600 - Radiation Chemistry