Mechanistic investigations of polyaza[7]helicene in photoredox and energy transfer catalysis
dc.contributor.author | Rocker, Johannes | |
dc.contributor.author | Zähringer, Till J. B. | |
dc.contributor.author | Schmitz, Matthias | |
dc.contributor.author | Opatz, Till | |
dc.contributor.author | Kerzig, Christoph | |
dc.date.accessioned | 2024-11-05T12:03:24Z | |
dc.date.available | 2024-11-05T12:03:24Z | |
dc.date.issued | 2024 | |
dc.description.abstract | Organic 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.doi | http://doi.org/10.25358/openscience-10879 | |
dc.identifier.uri | https://openscience.ub.uni-mainz.de/handle/20.500.12030/10898 | |
dc.language.iso | eng | de |
dc.rights | CC-BY-4.0 | * |
dc.rights.uri | https://creativecommons.org/licenses/by/4.0/ | * |
dc.subject.ddc | 540 Chemie | de_DE |
dc.subject.ddc | 540 Chemistry and allied sciences | en_GB |
dc.title | Mechanistic investigations of polyaza[7]helicene in photoredox and energy transfer catalysis | en_GB |
dc.type | Zeitschriftenaufsatz | de |
jgu.journal.title | Beilstein journal of organic chemistry | de |
jgu.journal.volume | 20 | de |
jgu.organisation.department | FB 09 Chemie, Pharmazie u. Geowissensch. | de |
jgu.organisation.name | Johannes Gutenberg-Universität Mainz | |
jgu.organisation.number | 7950 | |
jgu.organisation.place | Mainz | |
jgu.organisation.ror | https://ror.org/023b0x485 | |
jgu.pages.end | 1245 | de |
jgu.pages.start | 1236 | de |
jgu.publisher.doi | 10.3762/bjoc.20.106 | de |
jgu.publisher.issn | 1860-5397 | de |
jgu.publisher.name | Beilstein-Institut zur Förderung der Chemischen Wissenschaften | de |
jgu.publisher.place | Frankfurt/M. | de |
jgu.publisher.year | 2024 | |
jgu.rights.accessrights | openAccess | |
jgu.subject.ddccode | 540 | de |
jgu.subject.dfg | Naturwissenschaften | de |
jgu.type.dinitype | Article | en_GB |
jgu.type.resource | Text | de |
jgu.type.version | Published version | de |