Selective Fluorescence Quenching in Cationic Fluorene-Thiophene Diblock Copolymers for Ratiometric Sensing of Anions

Authors

  • Sofia M. Fonseca,

    Corresponding author
    1. Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal
    • Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal
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  • Rita P. Galvão,

    1. Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal
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  • Hugh D. Burrows,

    Corresponding author
    1. Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal
    • Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal
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  • Andrea Gutacker,

    Corresponding author
    1. Bergische Universität Wuppertal, Makromolekulare Chemie, Gaussstrasse 20, 42119 Wuppertal, Germany
    2. Center for Polymers and Organic Solids, Department of Physics and Chemistry & Biochemistry, University of California, Santa Barbara, California 93106, USA
    • Bergische Universität Wuppertal, Makromolekulare Chemie, Gaussstrasse 20, 42119 Wuppertal, Germany.
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  • Ullrich Scherf,

    1. Bergische Universität Wuppertal, Makromolekulare Chemie, Gaussstrasse 20, 42119 Wuppertal, Germany
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  • Guillermo C. Bazan

    1. Center for Polymers and Organic Solids, Department of Physics and Chemistry & Biochemistry, University of California, Santa Barbara, California 93106, USA
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Abstract

The cationic, all-conjugated AB diblock copolymer poly[9,9-bis(2-ethylhexyl)fluorene]-b-poly[3-(6-trimethylammoniumhexyl) thiophene] bromide (PF2/6-b-P3TMAHT) shows dual fluorescence from the poly(fluorene) (PF) and poly(thiophene) (PT) blocks. A comparison of fluorescence quenching of the cationic PT block fluorescence with unquenched PF block provides a sensitive ratiometric method for anion sensing. The application to analysis of halide ions, single- and double-stranded DNA is demonstrated. High selectivity is observed with halide ions, with the strongest quenching being seen with iodide. The quenching with DNA can be used for nucleic acid quantification at sub-μM concentrations.

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