A kinetic study of the one electron oxidation of substituted ferrocenes (FcX: X = H, COPh, COMe, CO2Et, CONH2, CH2OH, Et, and Me2) by a series of N-oxyl radicals (succinimide-N-oxyl radical (SINO), maleimide-N-oxyl radical (MINO), 3-quinazolin-4-one-N-oxyl radical (QONO) and 3-benzotriazin-4-one-N-oxyl radical (BONO)), has been carried out in CH3CN. N-oxyl radicals were produced by hydrogen abstraction from the corresponding N-hydroxy derivatives by the cumyloxyl radical. With all systems, the rate constants exhibited a satisfactory fit to the Marcus equation allowing us to determine self-exchange reorganization energy values (λNO˙/NO−) which have been compared with those previously determined for the PINO/PINO− and BTNO/BTNO− couples. Even small modification of the structure of the N-oxyl radicals lead to significant variation of the λNO˙/NO− values. The λNO˙/NO− values increase in the order BONO < BTNO < QONO < PINO < SINO < MINO which do not parallel the order of the oxidation potentials. The higher λNO˙/NO− values found for the MINO and SINO radicals might be in accordance with a lower degree of spin delocalization in the radicals MINO and SINO and charge delocalization in the anions MINO− and SINO− due to the absence of an aromatic ring in their structure.

Baciocchi, E., Bietti, M., D’Alfonso, C., Lanzalunga, O., Lapi, A., Salamone, M. (2011). One-Electron Oxidation of Ferrocenes by Short-Lived N-oxyl Radicals. The Role of Structural Effects on the Intrinsic Electron Transfer Reactivities. ORGANIC & BIOMOLECULAR CHEMISTRY, 9, 4085-4090 [10.1039/c0ob01257b].

One-Electron Oxidation of Ferrocenes by Short-Lived N-oxyl Radicals. The Role of Structural Effects on the Intrinsic Electron Transfer Reactivities

BIETTI, MASSIMO;SALAMONE, MICHELA
2011-04-07

Abstract

A kinetic study of the one electron oxidation of substituted ferrocenes (FcX: X = H, COPh, COMe, CO2Et, CONH2, CH2OH, Et, and Me2) by a series of N-oxyl radicals (succinimide-N-oxyl radical (SINO), maleimide-N-oxyl radical (MINO), 3-quinazolin-4-one-N-oxyl radical (QONO) and 3-benzotriazin-4-one-N-oxyl radical (BONO)), has been carried out in CH3CN. N-oxyl radicals were produced by hydrogen abstraction from the corresponding N-hydroxy derivatives by the cumyloxyl radical. With all systems, the rate constants exhibited a satisfactory fit to the Marcus equation allowing us to determine self-exchange reorganization energy values (λNO˙/NO−) which have been compared with those previously determined for the PINO/PINO− and BTNO/BTNO− couples. Even small modification of the structure of the N-oxyl radicals lead to significant variation of the λNO˙/NO− values. The λNO˙/NO− values increase in the order BONO < BTNO < QONO < PINO < SINO < MINO which do not parallel the order of the oxidation potentials. The higher λNO˙/NO− values found for the MINO and SINO radicals might be in accordance with a lower degree of spin delocalization in the radicals MINO and SINO and charge delocalization in the anions MINO− and SINO− due to the absence of an aromatic ring in their structure.
7-apr-2011
Pubblicato
Rilevanza internazionale
Articolo
Sì, ma tipo non specificato
Settore CHIM/06 - CHIMICA ORGANICA
English
Con Impact Factor ISI
Baciocchi, E., Bietti, M., D’Alfonso, C., Lanzalunga, O., Lapi, A., Salamone, M. (2011). One-Electron Oxidation of Ferrocenes by Short-Lived N-oxyl Radicals. The Role of Structural Effects on the Intrinsic Electron Transfer Reactivities. ORGANIC & BIOMOLECULAR CHEMISTRY, 9, 4085-4090 [10.1039/c0ob01257b].
Baciocchi, E; Bietti, M; D’Alfonso, C; Lanzalunga, O; Lapi, A; Salamone, M
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2108/13187
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