title: Light-harvesting properties of zinc complex of chlorophyll-a from spirulina in surfactant micellar media.
abstract: Zn chlorophyll-a was prepared from Mg chlorophyll-a from spirulina and the optical properties of the ground state and the photoexited state of Zn chlorophyll-a in aqueous surfactant micellar media were studied using UV-vis absorption, fluorescence emission spectra, electrochemical and fluorescence lifetime measurements. In comparison of the UV-vis absorption and fluorescence emission spectra of Zn chlorophyll-a and Mg chlorophyll-a, the blue-shift in the absorption bands and emission peak of Zn chlorophyll-a was observed. The energies of the first excited singlet state of Zn chlorophyll-a was 1.87 eV. The first oxidation and reduction potentials of the photoexcited singlet state of Zn chlorophyll-a were -0.67 and 0.60 V, respectively. Fluorescence lifetime of Zn chlorophyll-a was 9.0 ns in CTAB micellar solution. The fluorescence lifetime of Zn chlorophyll-a is shorter than that of Mg chlorophyll-a (9.8 ns). The photositability of Zn chlorophyll-a was superior to that of Mg chlorophyll-a in various pH conditions.
authors.affiliation: Department of Applied Chemistry, Oita University, Dannoharu 700, Oita 870-1192, Japan.
authors.forename: Yumi
authors.initials: Y
authors.lastname: Takeuchi
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Amao
mesh_terms: D000077286:Cetrimonium; D002593:Cetrimonium Compounds / Q000737:chemistry / Q000494:pharmacology; D002734:Chlorophyll / Q000737:chemistry*; D000077194:Chlorophyll A; D000458:Cyanobacteria / Q000378:metabolism*; D004563:Electrochemistry; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D008027:Light; D008274:Magnesium / Q000737:chemistry; D008823:Micelles; D008956:Models, Chemical; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry; D013050:Spectrometry, Fluorescence; D013053:Spectrophotometry; D013501:Surface-Active Agents / Q000737:chemistry*; D013997:Time Factors; D014466:Ultraviolet Rays; D015032:Zinc / Q000737:chemistry*
chemical_list: D002593:Cetrimonium Compounds; D008823:Micelles; D013501:Surface-Active Agents; D002734:Chlorophyll; D008274:Magnesium; D015032:Zinc; D010100:Oxygen; D000077194:Chlorophyll A; D000077286:Cetrimonium