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    刘迪

    • 教授     博士生导师   硕士生导师
    • 性别:男
    • 毕业院校:中科院理化所
    • 学位:博士
    • 所在单位:化学学院
    • 学科:有机化学
    • 办公地点:化工综合楼C501
    • 联系方式:liudi@dlut.edu.cn
    • 电子邮箱:liudi@dlut.edu.cn

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    Substituent and solvent effects on excited state intramolecular proton transfer in novel 2-(2 '-hydroxyphenyl)benzothiazole derivatives

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    论文类型:期刊论文

    发表时间:2009-06-10

    发表刊物:JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY

    收录刊物:SCIE

    卷号:205

    期号:1

    页面范围:61-69

    ISSN号:1010-6030

    关键字:Excited state intramolecolar proton transfer (ESIPT); Hydrogen bond; Dual fluorescence; 2-(2 '-Hydroxyphenyl)benzothiazole; Substituent effect

    摘要:A group of novel 2-(2'-hydroxyphenyl)benzothiazole derivatives 1-5 were synthesized with electron-donating or -withdrawing substituent introduced in para position of N atom in benzothiazolyl ring. The excited state intramolecular proton transfer (ESIPT) in 1-5 along with non-substituted 2-(2'-hydroxyphenyl)benzothiazole 6 was studied by means of UV-vis absorption and steady-state fluorescence in solutions. Compounds 1-6 exhibit dual fluorescences including purple normal emission and green tautomer emission. Systematical comparison of the fluorescence of any analogue in a series of solvents ranging from protic ethanol to non-polar hexane demonstrated that polar solvents favor the normal emission while non-polar solvents facilitate ESIPT process and tautomer formation and emission. In either protic or non-polar solvent the tautomer emission intensity of 1-6 decreases consecutively in the order of decreasing electron-donating ability or increasing electron-withdrawing ability of the substituents, oil the premise of identical normal emission intensity. This indicates that electron-donating substituents in these derivatives favor ESIPT process and tautomer emission. Competition of intra- and intermolecular hydrogen bonding was studied in dioxane-water binary solvent. It is demonstrated that intermolecular hydrogen bonding with protic solvent impedes ESIPT and tautomer emission. The fluorescent behaviors of 1-6 were interpreted in terms of the population of ground-state rotamers responsible for normal and tautomer emission respectively. (C) 2009 Elsevier B.V. All rights reserved.