Photoinduced hydrogen evolution by a Zwitterionic diquat electron acceptor. The functions of SiO/sub 2/ colloid in controlling the electron-transfer process

Journal Article · Wed Oct 05 04:00:00 EDT 1983 · J. Am. Chem. Soc.; (United States)

DOI:https://doi.org/10.1021/ja00358a006· OSTI ID:5514080

Degani, Y; Willner, I

Photosensitized hydrogen evolution from a basic aqueous silicon dioxide (SiO/sub 2/) colloid (pH 9 to 10) is accomplished with N,N'-bis-(3-sulfonatopropyl)-2,2'-bipyridinium (DQS/sup 0/) and colloidal platinum as mediating catalysts. In this system Ru(bpy)/sub 3//sup 2 +/ (ruthenium (bipyridium)/sub 3//sup 2 +/) acts as a photosensitizer and triethanolamine (TEOA) as ultimate electron donor. No hydrogen formation is observed in a homogeneous aqueous solution under similar conditions. The SiO/sub 2/ colloid affects the formation and stabilization of the intermediate photoproducts, Ru(bpy)/sub 3//sup 3 +/ and DQS/sup -/., by means of electrostatic interactions. The electric potential of the particles assists the separation of the products from the initial encounter cage complex and results in the repulsion of the reduced product, DQS/sup -/., from the colloidal interface. Consequently, the recombination rate of DQS/sup -/. with the oxidized product Ru(bpy)/sub 3//sup 3 +/ is retarded. The electrostatic functions of the colloid are confirmed by alteration of the ionic strength and pH of the colloid solution. The structure of DQS/sup 0/ was determined by X-ray crystallography. The compound crystallizes in space group P2/sub 1//n with unit cell dimensions of a = 10.392 (1) A, b = 22.390 (3) A, c = 8.235 (1) A, ..beta.. = 95.07 (2)/sup 0/, V = 1909 (1) A/sup 3/, and Z = 4. 4 figures, 4 tables.

• Research Organization: Hebrew Univ. of Jerusalem, Israel
• OSTI ID: 5514080
• Journal Information: J. Am. Chem. Soc.; (United States), Journal Name: J. Am. Chem. Soc.; (United States) Vol. 105:20; ISSN JACSA
• Country of Publication: United States
• Language: English

Related Subjects

08 HYDROGEN
080106* -- Hydrogen-- Production-- Biosynthesis & Photochemical Processes
14 SOLAR ENERGY
140505 -- Solar Energy Conversion-- Photochemical
Photobiological
& Thermochemical Conversion-- (1980-)
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400500 -- Photochemistry
ABSORPTION SPECTRA
ALCOHOLS
AMINES
AZINES
BIPYRIDINES
BOND ANGLE
BOND LENGTHS
CATALYTIC EFFECTS
CHALCOGENIDES
CHEMICAL REACTIONS
CHROMATOGRAPHY
COHERENT SCATTERING
COLLOIDS
COMPLEXES
CRYSTAL STRUCTURE
DATA
DIFFRACTION
DIMENSIONS
DISPERSIONS
DYE LASERS
ELECTROSTATICS
ELEMENTS
ENERGY-LEVEL TRANSITIONS
ESTERS
EXCITATION
EXPERIMENTAL DATA
GAS CHROMATOGRAPHY
HETEROCYCLIC COMPOUNDS
HYDROGEN PRODUCTION
HYDROXY COMPOUNDS
INFORMATION
LASERS
LENGTH
LIQUID LASERS
METALS
MOLECULAR STRUCTURE
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC SULFUR COMPOUNDS
OXIDATION
OXIDES
OXYGEN COMPOUNDS
PH VALUE
PHOTOCHEMICAL REACTIONS
PLATINUM
PLATINUM METALS
PYRIDINES
RADICALS
REAGENTS
REDUCTION
RUTHENIUM COMPLEXES
SCATTERING
SENSITIZERS
SEPARATION PROCESSES
SILICON COMPOUNDS
SILICON OXIDES
SPACE GROUPS
SPECTRA
SULFONIC ACID ESTERS
TRANSITION ELEMENT COMPLEXES
TRANSITION ELEMENTS
X-RAY DIFFRACTION