Photo-Chromium: Sensitizer for Visible-Light-Induced Oxidative C−H Bond Functionalization-Electron or Energy Transfer?
| Autor: | Aleksej Friedrich, Stefan Lochbrunner, Ute Resch-Genger, Till Opatz, Alexander M. Nauth, Eugenyi Ermilov, Katja Heinze, Norman Scholz, Sven Otto |
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| Rok vydání: | 2017 |
| Předmět: |
010405 organic chemistry
Singlet oxygen Organic Chemistry Intermolecular force chemistry.chemical_element 010402 general chemistry Photochemistry 01 natural sciences 0104 chemical sciences Analytical Chemistry chemistry.chemical_compound Chromium Electron transfer Intersystem crossing chemistry Excited state Singlet fission Reactivity (chemistry) Physical and Theoretical Chemistry |
| Zdroj: | ChemPhotoChem. 1:344-349 |
| ISSN: | 2367-0932 |
| Popis: | The chromium(III) sensitizer [Cr(ddpd)2]3+ - based on an earth-abundant metal center - possesses a unique excited state potential energy landscape (ddpd = N,N'-dimethyl-N,N'-dipyridine-2-ylpyridine-2,6-diamine). The very large energy gap between the redox active and substitutionally labile 4T2 state and the long-lived low-energy 2E spin-flip state enables a selective, efficient sensitization of triplet dioxygen to give singlet dioxygen. Ultrafast intersystem crossing after the Franck Condon point from the 4T2 to the 2E excited state within 3.5 ps precludes intermolecular electron transfer pathways from the ultrashort-lived excited 4T2 state. This specific excited state reactivity enables a selective visible light-induced C-H bond activation of tertiary amines with 1O2 and subsequent trapping with cyanide to yield alpha-aminonitriles in good to excellent yields. |
| Databáze: | OpenAIRE |
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