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Titolo:
CARBON-CARBON BONDS FUNCTIONING AS ELECTRON SHUTTLES - THE GENERATIONOF ELECTRON-RICH MANGANESE(II) SCHIFF-BASE COMPLEXES AND THEIR REDOX CHEMISTRY
Autore:
GALLO E; SOLARI E; RE N; FLORIANI C; CHIESIVILLA A; RIZZOLI C;
Indirizzi:
UNIV LAUSANNE,BCH,INST CHIM MINERALE & ANALYT CH-1015 LAUSANNE SWITZERLAND UNIV LAUSANNE,BCH,INST CHIM MINERALE & ANALYT CH-1015 LAUSANNE SWITZERLAND UNIV PERUGIA,DIPARTIMENTO CHIM I-06100 PERUGIA ITALY UNIV PARMA,DIPARTIMENTO CHIM I-43100 PARMA ITALY
Titolo Testata:
Journal of the American Chemical Society
fascicolo: 22, volume: 119, anno: 1997,
pagine: 5144 - 5154
SICI:
0002-7863(1997)119:22<5144:CBFAES>2.0.ZU;2-Q
Fonte:
ISI
Lingua:
ENG
Soggetto:
ENANTIOSELECTIVE AEROBIC EPOXIDATION; CRYSTAL-STRUCTURE; UNFUNCTIONALIZED OLEFINS; MODEL COMPLEXES; MAGNETIC-SUSCEPTIBILITY; MOLECULAR-OXYGEN; METAL-COMPLEXES; B-12 MODELS; OXIDATION; ALKALI;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
86
Recensione:
Indirizzi per estratti:
Citazione:
E. Gallo et al., "CARBON-CARBON BONDS FUNCTIONING AS ELECTRON SHUTTLES - THE GENERATIONOF ELECTRON-RICH MANGANESE(II) SCHIFF-BASE COMPLEXES AND THEIR REDOX CHEMISTRY", Journal of the American Chemical Society, 119(22), 1997, pp. 5144-5154

Abstract

The reduction of [Mn(II)-salophen] derivatives [salophen = N,N'-ethylenebis(salicylideneaminato) dianion] led to the formation of C-C bridged dimers. Such C-C bonds function as two electron shuttles in electron-transfer reactions. The reduction of [Mn(salophen)(THF)](2) (1) and [Mn(3,5-Bu(4)(t)salophen)(THF)](2) (3) with 2 equiv of sodium metal led to the corresponding single C-C bond bridged dimers, [Mn-2(salophen(2))Na-2(DME)4] (5) [salophen(2) C-C bonded salophen dimer] and [Mn-2(3,5-Bu(4)(t)salophen(2))Na-2(DME)(6)] (7), respectively. Complexes 5 and 7 undergo a further two electron reduction to Mn-2(salophen(2)*)Na-4(DME)(6)] (6) [salophen(2)'' = C-C doubly bended salophen dimer] and[Mn2(3,5-Bu(4)(t)salophen(2)*)Na-4(DME)(4)] (8), respectively, both containing a double C-C bridge. The obtention of [Mn-2{salophen(Me)CH2)}(2)Na-4(DME)(4)] (9) from Mn(salophen-Me-2)(THF)](2) (2) strongly supports the existence of free radical precursors in the formation of C-C bonds. Complex 6 has been used as a source of four electrons in a number of reactions, thus reduction of Ag+, PhCH2Cl, p-benzoquinone, and[Co-II(MeOsalen)] occurs with the regeneration of the starting material 1. The C-C bond cleavage is the source of electrons, without being involved in any reaction as a reactive site. With stronger oxidizing agents not only complexes 6 and 8 transfer the electrons stored at the C-C bonds but also the metal undergoes a change in the oxidation state. The reaction of 6 with dioxygen produces a novel form of di-mu-oxo-Mn(IV) dimers, where the salophen ligand displays a bridging bonding mode in [Mn-2(mu-salophen)(2)(mu-O)(2)] (15) and [Mn2(mu-3,5-Bu(t)salophen)(2)(mu-O)(2)] (16).

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Documento generato il 29/09/20 alle ore 23:48:10