Mechanistic investigations of polyaza[7]helicene in photoredox and energy transfer catalysis

dc.contributor.authorRocker, Johannes
dc.contributor.authorZähringer, Till J. B.
dc.contributor.authorSchmitz, Matthias
dc.contributor.authorOpatz, Till
dc.contributor.authorKerzig, Christoph
dc.date.accessioned2024-11-05T12:03:24Z
dc.date.available2024-11-05T12:03:24Z
dc.date.issued2024
dc.description.abstractOrganic photocatalysts frequently possess dual singlet and triplet photoreactivity and a thorough photochemical characterization is essential for efficient light-driven applications. In this article, the mode of action of a polyazahelicene catalyst (Aza-H) was investigated using laser flash photolysis (LFP). The study revealed that the chromophore can function as a singlet-state photoredox catalyst in the sulfonylation/arylation of styrenes and as a triplet sensitizer in energy transfer catalysis. The singlet lifetime is sufficiently long to exploit the exceptional excited state reduction potential for the activation of 4-cyanopyridine. Photoinduced electron transfer generating the radical cation was directly observed confirming the previously proposed mechanism of a three-component reaction. Several steps of the photoredox cycle were investigated separately, providing deep insights into the complex mechanism. The triplet-excited Aza-H, which was studied with quantitative LFP, is formed with a quantum yield of 0.34. The pronounced triplet formation was exploited for the isomerization reaction of (E)-stilbene to the Z-isomer and the cyclization of cinnamyl chloride. Catalyst degradation mainly occurs through the long-lived Aza-H triplet (28 µs), but the photostability is greatly increased when the triplet efficiently reacts in a catalytic cycle such that turnover numbers exceeding 4400 are achievable with this organocatalyst.en_GB
dc.identifier.doihttp://doi.org/10.25358/openscience-10879
dc.identifier.urihttps://openscience.ub.uni-mainz.de/handle/20.500.12030/10898
dc.language.isoengde
dc.rightsCC-BY-4.0*
dc.rights.urihttps://creativecommons.org/licenses/by/4.0/*
dc.subject.ddc540 Chemiede_DE
dc.subject.ddc540 Chemistry and allied sciencesen_GB
dc.titleMechanistic investigations of polyaza[7]helicene in photoredox and energy transfer catalysisen_GB
dc.typeZeitschriftenaufsatzde
jgu.journal.titleBeilstein journal of organic chemistryde
jgu.journal.volume20de
jgu.organisation.departmentFB 09 Chemie, Pharmazie u. Geowissensch.de
jgu.organisation.nameJohannes Gutenberg-Universität Mainz
jgu.organisation.number7950
jgu.organisation.placeMainz
jgu.organisation.rorhttps://ror.org/023b0x485
jgu.pages.end1245de
jgu.pages.start1236de
jgu.publisher.doi10.3762/bjoc.20.106de
jgu.publisher.issn1860-5397de
jgu.publisher.nameBeilstein-Institut zur Förderung der Chemischen Wissenschaftende
jgu.publisher.placeFrankfurt/M.de
jgu.publisher.year2024
jgu.rights.accessrightsopenAccess
jgu.subject.ddccode540de
jgu.subject.dfgNaturwissenschaftende
jgu.type.dinitypeArticleen_GB
jgu.type.resourceTextde
jgu.type.versionPublished versionde

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