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From DPZ to DTQ: Development of novel photocatalyst for the homo/heterogeneous photoredox applications.
Rok: 2025
Druh publikace: ostatní - přednáška nebo poster
Strana od-do: nestránkováno
Tituly:
Jazyk Název Abstrakt Klíčová slova
eng From DPZ to DTQ: Development of novel photocatalyst for the homo/heterogeneous photoredox applications. The modern photoredox catalysis enables redox reactions to proceed under mild conditions through a photochemical activation of diverse substrates. A suitable photocatalyst capturing the light energy and facilitating the electron transfer processes is essential for this approach. Typical examples of pure organic photocatalysts comprise xanthene and acridinium dyes, perylenediimides, and cyanoarenes. In 2014, dicyanopyrazines have entered the field of organic photocatalysts by introducing the highly active pyrazine DPZ, so far used in manifold photoredox reactions. Its mechanism of action and the catalytic activity has been elucidated through a recent photophysical and theoretical study. Further findings pointed to a facile Mallory-type photocyclization of DPZ to dithienoquinoxaline DTQ under the blue light irradiation. The DTQ proved to be tuneable photocatalyst in chemodivergent reductions of nitroaromatics towards the particular reduction stages, e.g. nitroso, azoxy, azo, and amino derivatives. The double excited *DTQ.–, an exceptionally strong organic reductant with the reduction power of –3 V, proved to be the active reducing species. Hence, the DTQ may act either as one-electron oxidant (3DTQ*) or reductant (*DTQ.–) using a single light source. The DTQ was further immobilized via a copolymerization strategy with styrene, yielding a polymer-bound photocatalyst iDTQ. The powdered and flexible monolithic column were prepared based on iDTQ that retain the key photophysical and catalytic parameters as compared to the homogeneous DTQ. The iDTQ was successfully applied in both batch and continuous-flow heterogeneous photocatalytic processes. dicyanopyrazine; copolymerization; photocatalysis