Photochemistry of compounds adsorbed into cellulose. 5. Solid-state reduction of methylviologen photosensitized by tris(2,2'-bipyridine)ruthenium(II)
Quenching of excited Ru(bpy)/sub 3//sup 2 +/ by methylviologen has been studied in a cellulose matrix by using both steady-state and pulsed laser photolysis techniques. The quenching was found to proceed via an adiabatic electron-transfer mechanism with a rate constant which depends exponentially on the reacting distance; k(r) = 1.0 x 10/sup 10/ exp(-0.46r) s/sup -1/. Due to Franck-Condon factors the back reaction is approximately 3 orders of magnitude slower. The cellulose medium acts as a reducing agent interfering with the back reaction which results in a long-lived steady-state yield of reduced methylviologen. This yield depends on the concentration of the reacting species and reaches a maximum value of 4.6% in the sample containing (Ru(bpy)/sub 3//sup 2 +/) = 0.01 mol dm/sup -3/ and (MV/sup 2 +/) = 0.04 mol dm/sup -3/. Other details of the reaction mechanism are also given. 21 references, 5 figures, 1 table.
- Research Organization:
- Univ. of Notre Dame, IN
- OSTI ID:
- 5262168
- Journal Information:
- J. Phys. Chem.; (United States), Journal Name: J. Phys. Chem.; (United States) Vol. 89:9; ISSN JPCHA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400500* -- Photochemistry
AZINES
BIPYRIDINES
CARBOHYDRATES
CELLULOSE
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
DATA
DE-EXCITATION
DECOMPOSITION
ELECTRON TRANSFER
ELEMENTS
ENERGY LEVELS
ENERGY TRANSFER
ENERGY-LEVEL TRANSITIONS
EXCITED STATES
EXPERIMENTAL DATA
HETEROCYCLIC COMPOUNDS
INFORMATION
KINETICS
LASERS
METALS
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
PHOTOLYSIS
PLATINUM METALS
POLYSACCHARIDES
PYRIDINES
RADIATIONLESS DECAY
REACTION KINETICS
RUTHENIUM
SACCHARIDES
SORPTIVE PROPERTIES
SURFACE PROPERTIES
TRANSITION ELEMENTS