Fused-Ring Derivatives of Quinoxalines: Spectroscopic Characterization and Photoinduced Processes Investigated by EPR Spin Trapping TechniqueReport as inadecuate




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1

Institute of Physical Chemistry and Chemical Physics, Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava, Radlinského 9, Bratislava SK-812 37, Slovak Republic

2

Institute of Chemistry, Slovak Academy of Sciences, Dúbravská cesta 9, Bratislava SK-845 38, Slovak Republic

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Institute of Organic Chemistry, Catalysis and Petrochemistry, Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava, Radlinského 9, SK-812 37 Bratislava, Slovak Republic

4

Institute of Inorganic Chemistry, Slovak Academy of Sciences, Dúbravská cesta 9, Bratislava SK-845 36, Slovak Republic





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Author to whom correspondence should be addressed.



Abstract 10-Ethyl-7-oxo-7,10-dihydropyrido2,3-fquinoxaline derivatives, synthesized as promising biologically-photobiologically active compounds were characterized by UV-vis, FT-IR and fluorescent spectroscopy. Photoinduced processes of these derivatives were studied by EPR spectroscopy, monitoring in situ the generation of reactive intermediates upon UVA λmax = 365 nm irradiation. The formation of reactive oxygen species and further oxygen- and carbon-centered radical intermediates was detected and possible reaction routes were suggested. To quantify the investigated processes, the quantum yields of the superoxide radical anion spin-adduct and 4-oxo-2,2,6,6-tetramethylpiperidine N-oxyl generation were determined, reflecting the activation of molecular oxygen by the excited state of the quinoxaline derivative. View Full-Text

Keywords: quinoxalines; photochemistry; EPR spectroscopy; spin trapping; UV-vis; fluorescence spectroscopy quinoxalines; photochemistry; EPR spectroscopy; spin trapping; UV-vis; fluorescence spectroscopy





Author: Zuzana Barbieriková 1,* , Dana Dvoranová 1, Maroš Bella 2,3, Viktor Milata 3, Adriana Czímerová 4 and Vlasta Brezová 1

Source: http://mdpi.com/



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