Aspects of artificial photosynthesis. Photosensitized electron transfer across bilayers, charge separation, and hydrogen production in anionic surfactant vesicles
Photosensitized electron transfer from tris(2,2'-bipyridine)ruthenium cation, Ru(bpy)/sub 3//sup 2 +/, to methylviologen, MV/sup 2 +/, has been investigated in the presence of negatively charged dihexadecyl phosphate, DHP, surfactant vesicles by steady state photolysis, fluorescence quenching, and nanosecond laser flash photolysis. Four different substrate-surfactant vesicle organizations have been used. In system I, Ru(bpy)/sub 3//sup 2 +/ was attached to the outer and MV/sup 2 +/ was placed onto the inner surfaces of DHP vesicles. In system II, MV/sup 2 +/ was attached to the outer and Ru(bpy)/sub 3//sup 2 +/ to the inner surfaces of DHP vesicles. In system III, both Ru(bpy)/sub 3//sup 2 +/ and MV/sup 2 +/ were localized on the outer surfaces of DHP vesicles. In system IV, both Ru(bpy)/sub 3//sup 2 +/ and MV/sup 2 +/ were localized on the inner surfaces of DHP vesicles. Extremely efficient electron transfers have been observed on the surfaces of surfactant vesicles in systems III and IV. Electron transfer from excited Ru(bpy)/sub 3//sup 2 +/ to MV/sup 2 +/ across the bilayers of vesicles in the presence of externally added EDTA in system I resulted in the formation of reduced methylviologen, MV/sup +/., up to 75% conversion with a quantum efficiency of 2.40 x 10/sup -2/. If additionally approx. 10/sup -5/ M PtO/sub 2/ was entrapped in the interiors of DHP vesicles in system I, MV/sup +/. promptly reformed with concomitant hydrogen evolution. Photolysis of this system leads to the net consumption of only EDTA at very low stoichiometric Ru(bpy)/sub 3//sup 2 +/, MV/sup 2 +/, and PtO/sub 2/ concentrations. Dynamics of these processes have been determined and their relevance to photochemical solar energy conversions is discussed.
- Research Organization:
- Texas A and M Univ., College Station
- OSTI ID:
- 6293229
- Journal Information:
- J. Am. Chem. Soc.; (United States), Vol. 103:10
- Country of Publication:
- United States
- Language:
- English
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ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
08 HYDROGEN
BIPYRIDINES
ELECTRON TRANSFER
PHOTOLYSIS
EDTA
PHOSPHORIC ACID ESTERS
PLATINUM OXIDES
CATALYTIC EFFECTS
RUBIDIUM COMPLEXES
BIOMIMETIC PROCESSES
ENERGY CONVERSION
EXPERIMENTAL DATA
HYDROGEN PRODUCTION
ALKALI METAL COMPLEXES
AMINO ACIDS
AZINES
CARBOXYLIC ACIDS
CHALCOGENIDES
CHELATING AGENTS
CHEMICAL REACTIONS
COMPLEXES
CONVERSION
DATA
DECOMPOSITION
ESTERS
HETEROCYCLIC COMPOUNDS
INFORMATION
NUMERICAL DATA
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
PLATINUM COMPOUNDS
PYRIDINES
TRANSITION ELEMENT COMPOUNDS
400500* - Photochemistry
080106 - Hydrogen- Production- Biosynthesis & Photochemical Processes