- Aerobic photocatalysed oxidation of alkanes in the presence of decatungstates: Products and effects of solvent and counter-ion of the catalyst
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The aerobic photocatalysed oxidation of alkanes in the presence of decatungstates Q4W10O32 (Q = Na, Me 4N, Pr4N, Bu4N, Hex4N) leads to hydropcroxldes as primary products. Nitrite solvents and organic counter-ions of the catalyst compete in this photooxidation with alkane substrate. The influence of this competition on quantum yield, rate and selectivity for the oxidation of adamantane is quantitatively evaluated. A catalytic cycle, describing the formation of primary and secondary oxidation products, is proposed.
- Ermolenko, Ludmila P.,Giannotti, Charles
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p. 1205 - 1210
(2007/10/03)
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- Photoinduced SET for the Functionalization of Alkanes
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Thermochemical cycles show that deprotonation of alkane radical cations is an exothermic process, and indeed photoinduced SET between several alkanes and 1,2,4,5-tetracyanobenzene (TCB) is followed by efficient deprotonation of the radical cation with tertiary > secondary > primary selectivity; the alkyl radical is trapped by TCB.- or, when present, by oxygen; when tetrachloro-p-benzoquinone is used in the place of TCB, the radical is further oxidized to the cation.
- Mella, Mariella,Freccero, Mauro,Albini, Angelo
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- Functionalization of Saturated Hydrocarbons. 14. Further Studies on the Mechanism of Gif-Type Systems
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The photolysis (W light) of acyl derivatives of N-hydroxy-2-thiopyridone in pyridine-acetic acid permits a study of the partioning of secondary radicals between oxygen, pyridine, and the thione function.Comparison with the GifIV oxidation system for saturated hydrocarbons confirms that radicals are not involved in oxidation at secondary positions.On the contrary, radical behavior at the tertiary position in adamantane is again established.The two recently introduced Gif-type systems, GoAggI and GoAggII, have been shown to give the same overall selectivity in attack on adamantane with the usual coupling of the tertiary radical with pyridine.
- Barton, Derek H. R.,Halley, Frank,Ozbalik, Nubar,Schmitt, Martine,Young, Esme,Balavoine, Gilbert
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p. 7144 - 7149
(2007/10/02)
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