Reactivity of ferrocenium cations with molecular oxygen in polar organic solvents: Decomposition, redox reactions and stabilization

Hurvois, Jean‐Pierre; Moinet, Claude

doi:10.1016/j.jorganchem.2005.02.009

Cited by 98 publications

(83 citation statements)

References 22 publications

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“…[58,67] All electrolyte solutions were rigorously purged with argon to prevent any reaction between the electrogenerated ferrocenium cation and residual molecular oxygen. [77] Electrochemical measurements were performed in a Faraday cage using purpose-built potentiostats able to achieve 100 % compensation of ohmic losses via positive-feedback circuitry. This enabled voltammetric probing in the ultrafast time domain, that is, up to scan rates as high as 2.5 MV s À1 .…”

Section: Methodsmentioning

confidence: 99%

Ultrafast Voltammetry for Probing Interfacial Electron Transfer in Molecular Wires

et al. 2007

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Electron transfer inside self-assembled monolayers made from complex redox-active oligophenylenevinylene molecular wires is examined by ultrafast cyclic voltammetry. Rate constants above 10(6) s(-1) are measured when the electroactive moieties are easily accessible to counterions from the electrolyte. These counterion movements are necessary to compensate the local charge created upon electron transfer. Conversely, if the redox center is buried within long hydrophobic diluents, the counterion movement towards the redox entity becomes rate limiting, thus drastically altering the rate magnitude and its physical meaning. This change in the mechanism is examined both for superexchange or when one electron-hopping step is involved.

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Section: Methodsmentioning

confidence: 99%

Ultrafast Voltammetry for Probing Interfacial Electron Transfer in Molecular Wires

et al. 2007

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“…10b, bottom). The irreversible electrochemical oxidation of Fc and its derivatives is well-known, but this effect is highly dependent on the experimental conditions such as electrode dimensions, the nature of the support electrolyte, the concentration of Fc functionalities together with the degree of ferrocene modification [29][30][31][32][33][34][35][36]. In a previous study [6], ethynyl Fc, Lip Fc and Fc-PVC in membranes that were plasticized by the ionic liquid, 1- exerts a similar influence on the reaction product formed from an aqueous electrolyte of 10 mM NaCl, which is due partially to severe suppression of the permeation of NaCl with water nanodroplets/ion exchange of Cl -from the aqueous electrolyte into these membranes containing very high concentrations of organic cations and anions in the IL plasticized membranes.…”

mentioning

confidence: 99%

Electrochemical Mechanism of Ferrocene-Based Redox Molecules in Thin Film Membrane Electrodes

Cuartero

Acres

Bradley

et al. 2017

Electrochimica Acta

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2 GRAPHICAL ABSTRACTCartoon illustrating NaCl permeation through water nanodroplets and Cl -exchange at the membrane/sample interface, both of which create an environment to enable the formation of FeCln 3-n complexes, leading to a non-reversibility in the redox chemistry of the membrane. RESEARCH HIGHLIGHTS electrochemistry of ferrocene derivatives in polymeric membranes  role of chloride on the irreversible oxidation of ferrocene in thin film membranes  synchrotron radiation study of chloride on the ferrocene reactivity in membranes  elimination of chloride induced irreversibility of the ferrocene reaction chemistry ABSTRACTCyclic voltammetry (CV) in chloride-based aqueous electrolytes of ferrocene molecule doped thin membranes (~200 nm in thickness) on glassy carbon (GC) substrate electrodes, both plasticized poly(vinyl chloride) (PVC) and unplasticized poly(methyl methacrylate)/poly(decyl methacrylate) (PMMA-PDMA) membranes, has shown that the electrochemical oxidation behavior is irreversible due most likely to 3 degradation of ferrocene at the buried interface (GC|membrane). Furthermore, CV of the ferrocene molecules at GC electrodes in organic solvents employing chloride-based and chloride-free organic electrolytes has demonstrated that the chloride anion is inextricably linked to this irreversible ferrocene oxidation electrochemistry. Accordingly, we have explored the electrochemical oxidation mechanism of ferrocenebased redox molecules in thin film plasticized and unplasticized polymeric membrane electrodes by coupling synchrotron radiation-X-ray photoelectron spectroscopy (SR-XPS) and near edge X-ray absorption fine structure (NEXAFS) with argon ion sputtering to depth profile the electrochemically oxidized thin membrane systems. With the PVC depth profiling studies, it was not possible to precisely study the influence of chloride on the ferrocene reactivity due to the high atomic ratio of chloride in the PVC membrane; however, the depth profiling results obtained with a chlorine-free polymer (PMMA-PDMA) provided irrefutable evidence for the formation of a chloride-based iron product at the GC|PMMA-PDMA interface. Finally, we have identified conditions that prevent the irreversible conversion of ferrocene by utilizing a high loading of redox active reagent and/or an ionic liquid (IL) membrane plasticizer with high ionicity that suppresses the mass transfer of chloride.

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“…Ferrocenium ions in oxygenated CH 2 Cl 2 solutions are known to undergo a decomposition reaction [36], the products of which have not been completely characterized, although there is indirect evidence that cyclopentadien-5-ol is formed [37]. The initial step in the process is apparently the formation of a ferrocene-oxygen complex, which has been suggested to consist of a peroxy bridge between two irons [37].…”

Section: Ferrocene In Deoxygenated Chloroformmentioning

confidence: 99%

“…The initial step in the process is apparently the formation of a ferrocene-oxygen complex, which has been suggested to consist of a peroxy bridge between two irons [37]. It has also been proposed that the ferrate ion, FeO 4 2-, is the ultimate iron product [37]. The decomposition reaction is more rapid in more polar solvents, instantaneous, in fact, in DMF and DMSO [37].…”

Section: Ferrocene In Deoxygenated Chloroformmentioning

confidence: 99%

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Ferrocene/ferrocenium ion as a catalyst for the photodecomposition of chloroform

Peña

Seidl

Cohen

et al. 2008

Transition Met Chem

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Irradiation (k [ 320 nm) of ferrocene in chloroform causes decomposition of chloroform and the accumulation of HCl, CCl 3 OOH, and C 2 Cl 6 . This appears to occur initially through a cycle in which (a) ferrocene is oxidized to ferrocenium and tetrachloroferrate ions, (b) FeCl 4 -undergoes photodissociation, and (c) ferrocenium reoxidizes the chloroferrate(II) species. On extended photolysis, the concentrations of CCl 3 OOH and FeCl 4 -build up and a competing cycle in which FeCl 4 -is restored through oxidation of the chloroferrate(II) species by CCl 3 OOH accelerates the decomposition rate.

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Reactivity of ferrocenium cations with molecular oxygen in polar organic solvents: Decomposition, redox reactions and stabilization

Cited by 98 publications

References 22 publications

Ultrafast Voltammetry for Probing Interfacial Electron Transfer in Molecular Wires

Ultrafast Voltammetry for Probing Interfacial Electron Transfer in Molecular Wires

Electrochemical Mechanism of Ferrocene-Based Redox Molecules in Thin Film Membrane Electrodes

Ferrocene/ferrocenium ion as a catalyst for the photodecomposition of chloroform

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