Influence of energetic excitation on the structure and location of the radical II in X-irradiated Rochelle salt studied by ENDOR

Treeck, E van; Windsch, W.

doi:10.1016/0022-2364(77)90115-9

Cited by 3 publications

(2 citation statements)

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“…The Rochelle salt, being the Na, K-salt of tartaric acid, is of particular interest as it exhibits ferroelectricity in the solid state (Solans et al, 1997). The nature of the radicals formed in Rochelle salt was investigated to obtain some understanding of the mechanisms producing changes in the ferroelectric properties of this compound upon irradiation (Moulton and Moulton, 1961;Suzuki and Abe, 1967;Suzuki and Abe, 1968;Suzuki, 1974;van Treek and Windsch, 1977).…”

Section: Introductionmentioning

confidence: 99%

“…The assignment issue was therefore also addressed using density functional theory (DFT)-type quantum chemical calculations. Additional calculations were made concerning the nature of the previously studied radicals at room temperature (Moulton and Moulton, 1961;Suzuki and Abe, 1967;Suzuki and Abe, 1968;Suzuki, 1974;van Treek and Windsch, 1977).…”

Section: Introductionmentioning

confidence: 99%

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Free radical products in X-irradiated Rochelle salt: low temperature ENDOR and DFT studies

Sagstuen

Hole

Lund

2012

Radiation Physics and Chemistry

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Abstractreactions upon warming. The one-electron gain product was observed and from the hyperfine interaction with a β-proton it was unambiguously centred at the C 4 position of the tartrate moiety. An additional nearly isotropic hyperfine structure of about 21 MHz was tentatively assigned to interaction with a sodium ion exhibiting a close contact to O 3 in the crystal.Evidence was obtained that the one-electron reduced radical had become protonated at one of the C 4 bonded carboxyl oxygens, most probably O 4 . No evidence for the corresponding C 1 -centred reduction product was found. Two resonance lines (R2, A1) were shown by EIE to belong to a species formed by decarboxylation at C 3 , a secondary oxidation product. Two other resonance lines (K1, K2) were assigned to two varieties of another decarboxylation radical, centred at C 2 , distinguished by differences in the potassium ion coordination.Furthermore, one other resonance line (A2) was tentatively ascribed to a third decarboxylation radical, centred at the opposite end of the tartrate moiety. The precursor of these products, that is, the one-electron loss product, was not observed after X-irradiation at 10 K. Thermally induced free radical reactions followed by EPR in the temperature range 12 to 119 K indicate that a water molecule or a hydroxyl ion is eliminated from the one-electron reduction product radical and that a C 3 -centred radical is formed. The reduction and oxidation reaction pathways of hydroxy acid derivatives are discussed.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Free radical products in X-irradiated Rochelle salt: low temperature ENDOR and DFT studies

Sagstuen

Hole

Lund

2012

Radiation Physics and Chemistry

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Endor studies of free radicals trapped in X-ray irradiated single crystals of caffeine hydrochloride dihydrate

Lenard

McDowell

1984

Journal of Molecular Structure

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Primary reactions in crystalline Rochelle salt studied by pulse radiolysis and EPR spectroscopy. The decarboxylation of the acyloxy radical ion

Samskog

Nilsson

Lund

1978

The Journal of Chemical Physics

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The acyloxy radical ion −O2CCHODCHODCȮ2 (I) was identified in irradiated Rochelle salt by combining the techniques of pulse radiolysis and EPR spectroscopy. This primary radical gives hyperfine couplings due to 13C, 1H, and 23Na and has a broad optical absorption band with the peak at 405 nm. It decomposes by decarboxylation in a first order decay. The half life at 22 °C is 55 ns and the activation energy for decarboxylation is 7.5 kcal mol−1. The G value for the CO2 formation is 2.7 and the extinction coefficient of I is 900M−1 cm−1. No effects of the ferroelectricity of the salt on εmaxG were found.

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Influence of energetic excitation on the structure and location of the radical II in X-irradiated Rochelle salt studied by ENDOR

Cited by 3 publications

References 7 publications

Free radical products in X-irradiated Rochelle salt: low temperature ENDOR and DFT studies

Free radical products in X-irradiated Rochelle salt: low temperature ENDOR and DFT studies

Endor studies of free radicals trapped in X-ray irradiated single crystals of caffeine hydrochloride dihydrate

Primary reactions in crystalline Rochelle salt studied by pulse radiolysis and EPR spectroscopy. The decarboxylation of the acyloxy radical ion

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