中国科学院机构知识库网格
Chinese Academy of Sciences Institutional Repositories Grid
Mechanism of radical cation formation from the excited states of zeaxanthin and astaxanthin in chloroform

文献类型:期刊论文

作者Han, RM; Tian, YX; Wu, YS; Wang, P; Ai, XC; Zhang, JP; Skibsted, LH
刊名PHOTOCHEMISTRY AND PHOTOBIOLOGY
出版日期2006-03-01
卷号82期号:2页码:538-546
ISSN号0031-8655
DOI10.1562/2005-09-30-RA-705
英文摘要The C-40 xanthophylls zeaxanthin and astaxanthin were confirmed to form radical cations, Car(.+), in the electron-accepting solvent chloroform by direct excitation using subpicosecond time-resolved absorption spectroscopy in combination with spectroelectrochemical determination of the near-infrared absorption of Car(.+). For the singlets, the S-2(1B(u)(+)) state and most likely the S-x(3A(g)(-)) state directly eject electrons to chloroform leading to the rapid formation of Car(.+) on a timescale of similar to 100 fs; the lowest-lying S-1(2A(g)(-)) state, however, remains inactive. Standard reduction potential for Car(.+) was determined by cyclic voltametry to have the value 0.63 V for zeaxanthin and 0.75 V for astaxanthin from which excited state potentials were calculated, which confirmed the reactivity toward radical cation formation. On the other hand, Car(.+) formation from the lowest triplet excited state T-1 populated through anthracene sensitization is mediated by a precursor suggested to be a solute-solvent complex detected with broad near-infrared absorption to the shorter wavelength side of the characteristic Car(.+) absorption. However, ground state carotenoids are able to react with a secondary solvent radical to yield Car(.+), a process occurring within 16 mu s for zeaxanthin and within 21 mu s for astaxanthin. Among the two xanthophylls together with lycopene and beta-carotene, all having 11 conjugated double bonds, zeaxanthin ranks with the highest reactivity in forming Car(.+) from either the S-2(1B(u)(+)) or the ground state. The effects of substituent groups on the reactivity are discussed.
语种英语
WOS记录号WOS:000237048300029
出版者AMER SOC PHOTOBIOLOGY
源URL[http://ir.iccas.ac.cn/handle/121111/59013]  
专题中国科学院化学研究所
通讯作者Zhang, JP
作者单位1.Chinese Acad Sci, Inst Chem, State Key Lab Struct Chem Unstable & Stable Speci, Beijing, Peoples R China
2.Royal Vet & Agr Univ, Dept Food Sci, Frederiksberg C, Denmark
推荐引用方式
GB/T 7714
Han, RM,Tian, YX,Wu, YS,et al. Mechanism of radical cation formation from the excited states of zeaxanthin and astaxanthin in chloroform[J]. PHOTOCHEMISTRY AND PHOTOBIOLOGY,2006,82(2):538-546.
APA Han, RM.,Tian, YX.,Wu, YS.,Wang, P.,Ai, XC.,...&Skibsted, LH.(2006).Mechanism of radical cation formation from the excited states of zeaxanthin and astaxanthin in chloroform.PHOTOCHEMISTRY AND PHOTOBIOLOGY,82(2),538-546.
MLA Han, RM,et al."Mechanism of radical cation formation from the excited states of zeaxanthin and astaxanthin in chloroform".PHOTOCHEMISTRY AND PHOTOBIOLOGY 82.2(2006):538-546.

入库方式: OAI收割

来源:化学研究所

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