The Charge Transfer Photochemistry of the Hexaaquoiron(III) Ion, the Chloropentaaquoiron(III) Ion, and the µ-Dihydroxo Dimer Explored with <i>tert</i>-Butyl Alcohol Scavenging

Langford, Cooper H.; Carey, John H.

doi:10.1139/v75-344

Cited by 109 publications

(43 citation statements)

References 7 publications

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“…4 The absorption peak at 230 nm can be attributed to Feaq3+.5 The absorption spectrum became structureless at pH 3.35, suggesting the formation of association species of Fe3+ and OH-such as FeOH2+, Fe(OH)2+, and Fe2(OH)*4+. 5 The initial step following the photoexcitation of ferric complexes of the type FeX2+, where X is OH or C1, is the production of ferrous ion and free radical species in solution. 6 The recombination of radical X with ferrous ion reported that PVA was an efficient scavenger for the radical X in aqueous solution.…”

Section: Resultsmentioning

confidence: 99%

Photoreduction of ferric chloride in poly(vinyl alcohol) film

Shirai

Ohuchi

Tsunooka

et al. 1982

J of Applied Polymer Sci

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It is well known that poly(viny1 alcohol) forms a blue-colored complex with iodine.' On the other hand, iodide is oxidized to iodine by ferric chloride, which loses its oxidizing ability by the photoreduction to ferrous salt. A photosensitive paper was designed on the basis of a combination of the above photochemical and thermal reactions.2 After drying a paper coated with an aqueous solution of poly(viny1 alcohol) containing ferric chloride, it was irradiated with UV light, followed by dipping into a KI solution. A clear image appeared on the paper by formation of a poly(viny1 alcohol)-iodine complex only at the part unexposed to UV light. The photosensitivity of the paper, however, was not satisfactory because of a low quantum yield for the photoreduction of ferric chloride. In this paper, we wish to report studies on the photoreduction of ferric chloride in poly(viny1 alcohol) film, which is of great importance in relation to an improvement of the photosensitivity of the photosensitive paper. EXPERIMENTALA commercially available poly(viny1 alcohol) (PVA, P,, = 500) was used after extraction with

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Section: Resultsmentioning

confidence: 99%

Photoreduction of ferric chloride in poly(vinyl alcohol) film

Shirai

Ohuchi

Tsunooka

et al. 1982

J of Applied Polymer Sci

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“…Such a reaction has now been observed in the ferric perchlorate/perchloric acid systeri when methanol, isopropanol, and formic acid were used as scavengers (3,4). Of the scavengers studied, tert-butyl alcohol was the only one that was efficient enough to react with all hydroxyl radicals and yet not undergo reaction directly with the excited state.…”

Section: K2mentioning

confidence: 85%

“…The iron(I1) yields were determined using o-phenanthroline and the neutralization dilution technique previously described (3). When copper was present, a blue crystalline precipitate usually formed during the analysis.…”

Section: Analytical Proceduresmentioning

confidence: 99%

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The photoreduction of hexaaquoiron(III) perchlorate in the presence of tertiary aliphatic alcohols. The effect of added copper

Carey¹,

Oliver²,

Langford³

1977

Can. J. Chem.

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The irradiation of ferric perchlorate in the presence of tert-amyl alcohol produces Fe(II) with a quantum yield of 0.110 ± 0.002, 12% lower than the yield obtained when tert-butyl alcohol was used as scavenger. Other tertiary alcohols studied, 3-methyl-2-pentanol and 3-ethyl-3-pentanol, exhibited similar lower yields. It is shown that this reduction is due to the formation of γ-hydroxyalkyl radicals which do not reduce ferric ion to ferrous. The addition of copper causes these radicals to be oxidized. The Fe(II) quantum yield for the irradiation with tertiary amyl alcohol as scavenger in the presence of copper is in good agreement with the tertiary butyl alcohol results in the absence of copper (0.124 ± 0.003).Quantum yields are observed which are independent of scavenger concentration indicating outer sphere photooxidations are not taking place. This result supports the suggestion that an H on the carbon bearing oxygen is necessary for direct reaction between scavenger and the ferric charge transfer excited state.

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“…Firstly, a charge transfer transition from a water centred orbital to an iron centred orbital produces OH. radicals which react with the organics via hydrogen abstraction (1). Secondly, the direct reaction of charge transfer excited states of iron(II1) species can lead to outer sphere oxidation (2).…”

Section: Introductionmentioning

confidence: 99%

The photolysis of hexaaquoiron(III) perchlorate in the presence of ethylene glycol

Carey¹,

Cosgrove²,

Oliver³

1977

Can. J. Chem.

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. Can. J. Chem. 55, 625 (1977). Two types of reactions occur when hexaaquoiron(II1) ion is irradiated at 254 nm in the presence of alcohols. Firstly, a charge transfer transition from a water centred orbital to an iron centred orbital produces OH' radicals which go on to abstract hydrogen from the alcohols. secondly ,!the reaction with the charge transfer excited states of iron(II1) species can lead to outer sphere oxidation of the alcohols. In this paper, these reactions have been studied in detail for the diol ethylene glycol in aqueous solutions. It has been found that the quantum yield of acetaldehyde, the major product of hydroxyl radical reactions with ethylene glycol, is 0.09 and the yield of formaldehyde, the major product of the direct charge transfer reaction, is 0.05 in 1 M ethylene glycol. The quantum yields for these major products, as well as minor products. such as glycolaldehyde and succinaldehyde, have been determined at several concentrations of ethylene glycol and iron. A detailed reaction scheme for the photolysis has been developed. JOHN H. CAREY, ERNEST G. COSGROVE et BARRY G. OLIVER. Can. J. Chem. 55, 625 (1977) I1 y a deux types de rCaction qui se produisent lorsque l'ion hexaaquofer(II1) est irradiC a 254 nm en presence d'alcools. En premier lieu, il y a une transition de transfert de charge a partir d'une orbitale centree au niveau de I'eau vers une orbitale centree sur le fer qui produit des radicaux O H qui ensuite enlevent de l'hydrogene des alcools. Deuxiemement il y a une reaction avec les Ctats excites de transfert de charge des espkces du fer(II1) qui peut conduire a des oxydations par les sphkres extCrieures de l'alcool. Dans la prCsente communication, on a Ctudit ces rkactions en detail pour le diol ethylene glycol en solution aqueuse. On a trouve que le rendement quantique d'acCtaldChyde, le produit majeur des reactions du radical hydroxyle avec l'ethylene glycol, est de 0.09 et le rendenlent de formaldehyde, qui est le produit majeur de la reaction de transfert directe de charge, est de 0.05 dans 1'6thyltne glycol 1 M. On a determine les rendements quantiques de ces produits majeurs ainsi que des produits mineurs tel que le glycolaldthyde et le succinaldthyde a plusieurs concentrations d'ethylene glycol et de fer. On a developpe un schema rtactionnel dttaillt pour la photolyse.[Traduit par le journal]

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The Charge Transfer Photochemistry of the Hexaaquoiron(III) Ion, the Chloropentaaquoiron(III) Ion, and the µ-Dihydroxo Dimer Explored with tert-Butyl Alcohol Scavenging

Cited by 109 publications

References 7 publications

Photoreduction of ferric chloride in poly(vinyl alcohol) film

Photoreduction of ferric chloride in poly(vinyl alcohol) film

The photoreduction of hexaaquoiron(III) perchlorate in the presence of tertiary aliphatic alcohols. The effect of added copper

The photolysis of hexaaquoiron(III) perchlorate in the presence of ethylene glycol

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