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RESEARCH PRODUCT
Photo-Chromium: Sensitizer for Visible-Light-Induced Oxidative C−H Bond Functionalization-Electron or Energy Transfer?
Aleksej FriedrichStefan LochbrunnerUte Resch-gengerTill OpatzAlexander M. NauthEugenyi ErmilovKatja HeinzeNorman ScholzSven Ottosubject
010405 organic chemistrySinglet oxygenOrganic ChemistryIntermolecular forcechemistry.chemical_element010402 general chemistryPhotochemistry01 natural sciences0104 chemical sciencesAnalytical Chemistrychemistry.chemical_compoundChromiumElectron transferIntersystem crossingchemistryExcited stateSinglet fissionReactivity (chemistry)Physical and Theoretical Chemistrydescription
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.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2017-07-26 | ChemPhotoChem |