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Download fileTwo-Dimensional, Acene-Containing Conjugated Polymers That Show Ratiometric Fluorescent Response to Singlet Oxygen
journal contribution
posted on 13.10.2015, 00:00 authored by Esra Altınok, Zachary
C. Smith, Samuel W. ThomasThis paper describes two-dimensional
conjugated poly(phenylene–ethynylene)s
(PPEs) linked to singlet oxygen-reactive diethynyltetracene units
through phenylene–ethynylene (PE) bridges that are conjugated
to the polymer backbones. Successive Sonogashira coupling reactions
enabled the preparation of the tetracene-containing PE pendants, the
linking of the pendants to the monomer unit, and the polymerization
reactions. Small molecule models of the polymers showed ratiometric
responses of fluorescence upon exposure to photogenerated singlet
oxygen due to cycloaddition reactions increasing the excited state
of individual chromophores. The fluorescent responses of the tetracene-linked
PPEs, however, showed markedly different behavior: (i) an initial
increase in fluorescence intensity and fluorescence lifetime of the
side-chain tetracenes upon exposure to 1O2 indicated
an analyte-induced slowing of self-quenching due to high local acene
concentration, and (ii) ratiometric blue-shifted response did not
occur until approximately 75% of pendant acenes were oxidized, highlighting
the potential utility of analyte-induced removal of traps in light-harvesting
fluorescent materials.
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Keywords
ratiometric responsescycloaddition reactionsfluorescence intensitySinglet OxygenThis paperSmall molecule modelsPEpolymer backbonesSuccessive Sonogashirafluorescence lifetimepolymerization reactions1 O 2pendant acenesmonomer unitacene concentrationPPEexposurephotogenerated singlet oxygenShow Ratiometric