Efficient photoinduced charge separation in layered zirconium viologen phosphonate compounds

Journal Article · Wed Dec 15 04:00:00 EST 1993 · Journal of the American Chemical Society; (United States)

DOI:https://doi.org/10.1021/ja00078a015· OSTI ID:7046962

Vermeulen, L A; Snover, J L; Sapochak, L S; Thompson, M E ^[1]

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1. Princeton Univ., NJ (United States)

Stable photoinduced charge separation has been observed in layered zirconium viologen phosphonate compounds, i.e. Zr(O[sub 3]PCH[sub 2]CH[sub 2](bipyridinium)CH[sub 2]CH[sub 2]PO[sub 3]) X[sub 2] (X = Cl, Br, I), ZrPV(X). Photolysis of these crystalline solids results in the formation of the blue viologen radical cation which is stable in air. Studies of these microcrystalline solids as well as related thin films are presented. Transparent thin films of ZrPV(Cl) were grown directly onto fused silica substrates from aqueous solution. Photoreduction of viologen in these thin-film samples is very efficient (quantum yield = 0.15), showing simple isobestic behavior in the electronic spectra. Contrary to the bulk solids, the photoreduced thin films are very air sensitive. Photophysical data is presented, which shows that the primary photoprocess involves a viologen-centered excitation, followed by oxidation of a halide anion. Subsequent reactions lead to the formation of a stable charge-separated state. Significant deuterium isotope effects (k[sub H]/k[sub D] = 3) for selectively labeled compounds suggest that the oxidized halide ions abstract hydrogen atoms from the methylene groups of ZrPV(Cl). NMR studies of these materials show that a number of different structural rearrangements are then involved in the formation of the ultimate charge-separated state. 33 refs., 8 figs.

• OSTI ID: 7046962
• Journal Information: Journal of the American Chemical Society; (United States), Journal Name: Journal of the American Chemical Society; (United States) Vol. 115:25; ISSN JACSAT; ISSN 0002-7863
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
140505* -- Solar Energy Conversion-- Photochemical
Photobiological
& Thermochemical Conversion-- (1980-)
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400102 -- Chemical & Spectral Procedures
400500 -- Photochemistry
CHALCOGENIDES
CHEMICAL REACTIONS
CONVERSION
DECOMPOSITION
DEUTERIUM COMPOUNDS
ENERGY CONVERSION
FILMS
HYDROGEN COMPOUNDS
MAGNETIC RESONANCE
MINERALS
NUCLEAR MAGNETIC RESONANCE
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
PHOTOLYSIS
RESONANCE
SILICA
SILICON COMPOUNDS
SILICON OXIDES
SOLAR ENERGY CONVERSION
SYNTHESIS
THIN FILMS
TRANSITION ELEMENT COMPOUNDS
ZIRCONIUM COMPOUNDS