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The effect of protonation on the excited state dynamics of pyrimidine chromophores
Authors: Kournoutas Fotis | Kalis Ioannis Konstantinos | Fecková Michaela | Achelle Sylvain | Fakis Mihalis
Year: 2020
Type of publication: článek v odborném periodiku
Name of source: Journal of Photochemistry and Photobiology A-Chemistry
Publisher name: Elsevier Science SA
Place: Lausanne
Page from-to: "112398-1"-"112398-7"
Titles:
Language Name Abstract Keywords
cze Efekt protonace na dynamiku excitovaného stavu pyrimidinových chromoforů Byl studován efekt protonace na fotofyziku dvou pyrimidinových chromoforů prostřednictvím fluorescenční spektroskopie. Byly využity tři kyseliny, kafrsulfonová, octová a trifluoroctová. pyrimidinové chromofory; protonace; dynamika; fluorescenční spektroskopie
eng The effect of protonation on the excited state dynamics of pyrimidine chromophores The effect of protonation on the photophysics and especially on the excited state dynamics of two pyrimidine chromophores, bearing the A-(pi-D)(2) and A-(pi-D)(3) structure, is studied by means of fs-ps and ns time resolved fluorescence spectroscopy. Three different acids, namely camphorsulphonic (CSA), acetic (AcOH) and trifluoroacetic acid (TFA) were used. The chromophores bear the pyrimidine electron deficient heterocycle as electron-withdrawing group, used as protonation site, as well as diphenylamino electron donors. Protonation is revealed through the emergence of red-shifted absorption and fluorescence bands accompanied by a quenching of the fluorescence of the neutral molecules. Time-resolved dynamics reveal that protonation with CSA and TFA do not influence the excited state lifetime of the chromophores, pointing to a static quenching process. On the other hand, the lifetime is decreased upon protonation with AcOH. Further investigation based on the Stern-Vollmer plots showed that addition of AcOH leads to both dynamic and static quenching. Pyrimidine chromophores; Protonation; Dynamics; Fluorescence spectroscopy