Photochemistry and Photobiology · 1988 · 121 citations · 27 references
Natural SciencesBiophysicsChemistryBiophotonicsBiophysical ChemistryLipid BiochemistryOxidative Damage To BiomoleculesOxygen EvolutionPhosphorescence SpectroscopyPhotochemical KineticsPhotochemistryReactive Oxygen SpeciesFluorescence Quantum YieldIrradiation ConditionsLight ExposureLiposomesPhotochemical Quantum YieldPhotooxidationSinglet Oxygen GenerationSmall Unilamellar Vesicles
Abstract— Zn(II)phthalocyanine (ZnPc) generates O 2 ( 1 Δ g ) with a quantum yield of ca. 0.4 upon photocxcitation at 354 or 600 nm in ethanolic solution as determined by time‐resolved phosphorescence studies at 1270 nm and photooxidation experiments using 1,3‐diphenylisobenzofuran (DPBF) as substrate. The quantum yield of photooxidation slightly increases upon incorporation of ZnPc into unilamellar liposomes of dipalmitoylphosphatidylcholine. Under our irradiation conditions (600 nm, 18 ° C, and short light exposure times), DPBF(5–50 μM) undergoes photooxidation by a pure Type II mechanism; the rate constant for the O 2 ( 1 Δ g ) + DPBF reaction is (1.1 ±0.1) x 10 9 M ‐1 s _1 in ethanol solution and determined to be about two orders of magnitude smaller when both ZnPc and DPBF are embedded into liposomes.
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