Function of SiO/sub 2/ colloids in photoinduces redox reactions. Interfacial effects on the quenching, charge separation, and quantum yields. [Propyl viologen sulfonate]
The function of negatively charged colloidal SiO/sub 2/ particles in controlling photosensitized electron-transfer reactions by means of electrostatic interactions between the different components in the system has been studied under steady-state conditions of illumination and by flash photolysis. In particular, the photosensitized reduction of the zwitterionic electron acceptor, propyl viologen sufonate, PVS/sup 0/ (1), using tris(2,2'-bipyridinium)ruthenium(II), Ru(bpy)/sub 3//sup 2 +/, as sensitizer has been investigated in the SiO/sub 2/ colloid and compared to the homogeneous system. Fluorescence quenching studies indicate that the quenching reaction of Ru(bpy)/sub 3//sup 2 +/ with the neutral PVS/sup 0/ is not affected by electrostatic interactions exerted by the negatively charged SiO/sub 2/ interface (k/sub q/ = 1.5 x 10/sup 9/ M/sup -1/s/sup -1/). In contrast, the quenching of Ru(bpy)/sub 3//sup 2 +/ by the positively charged methylviologen, MV/sup 2 +/, is strongly enhanced by the SiO/sub 2/colloid (k/sub q/ = 5 x 10/sup 10/ M/sup -1/s/sup -1/.
- Research Organization:
- Lawrence Berkeley Lab., CA
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 6071393
- Journal Information:
- J. Phys. Chem.; (United States), Journal Name: J. Phys. Chem.; (United States) Vol. 85:22; ISSN JPCHA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400500* -- Photochemistry
AMINES
AZINES
BIPYRIDINES
CHALCOGENIDES
CHEMICAL REACTIONS
COLLOIDS
COMPLEXES
DECOMPOSITION
DISPERSIONS
DYE LASERS
ELECTRON TRANSFER
ESTERS
FLUORESCENCE
HETEROCYCLIC COMPOUNDS
LASERS
LIQUID LASERS
LUMINESCENCE
MINERALS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC SULFUR COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PH VALUE
PHOTOCHEMICAL REACTIONS
PHOTOLYSIS
POTENTIALS
PYRIDINES
RECOMBINATION
REDUCTION
RUTHENIUM COMPLEXES
SCINTILLATION QUENCHING
SILICA
SILICON COMPOUNDS
SILICON OXIDES
SULFONIC ACID ESTERS
SURFACE POTENTIAL
TEMPERATURE DEPENDENCE
TRANSITION ELEMENT COMPLEXES