ChemInform Abstract: RK. VON URANYLNITRAT MIT ARSENAZO III IN SALPETERSAURER LOESUNG

Klygin, A.E.; Smirnova, Yu. D.; Kolyada, N.S.

doi:10.1002/chin.197110044

Cited by 2 publications

(4 citation statements)

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“…Lahr and Knoch found evidence for the formation of UO 2 (NO 3 ) 2 (aq) in solutions of HNO 3 with concentration varying in the range 0−8 M HNO 3 . The same has been supported by the spectrophotometric study of Klygin et al, who found no evidence for HUO 2 NO 3 but found evidence instead for HUO 2 (NO 3 ) 3 (aq) too . Lahr and Knoch also found evidence for the formation of HUO 2 (NO 3 ) 3 .…”

Section: Resultsmentioning

confidence: 71%

“…Figure shows the time-resolved absorption spectra of the transient species created following photoexcitation of uranyl nitrate dissolved in methanol using 400 nm laser pulses. We observed degradation of the sample following photoexcitation because of reaction between the triplet excited state of UO 2 2+ ion via abstraction of a hydrogen atom from the solvent molecule. ,− Hence special care has been taken for replacement of the sample during acquisition of the spectra. However, it is important to remember that we are concerned here with the dynamics of the shorter-lived excited states prior to the formation of the longer lived lowest excited triplet state, which undergoes the photochemical reduction reaction .…”

Section: Resultsmentioning

confidence: 99%

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Ultrafast Dynamics of the Excited States of the Uranyl Ion in Solutions

et al. 2010

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We have investigated the relaxation dynamics of the higher excited states of the uranyl ion in aqueous and methanolic solutions following photoexcitation to the S(1)((1)Phi(g)) state using 400 nm light. Although the time-resolved spectra are significantly different in these two solvents, the temporal dynamics studied in the entire wavelength region clearly suggest the involvement of three excited state processes in both solvents. The S(1)((1)Phi(g)) state undergoes ultrafast intersystem crossing (tau(ISC) approximately <100 fs) to the higher vibrational levels of the T(2)((3)Delta(g)) state, followed by the intramolecular vibrational relaxation (IVR) process in the later electronic state (tau(IVR) approximately 0.85 and 1 ps in aqueous and methanolic solutions, respectively). Subsequently, the T(2)((3)Delta(g)) state undergoes an internal conversion (IC) process (tau(IC) approximately l.6 and 4.5 ps in aqueous and methanol solutions, respectively) to the long-lived T(1)((3)Phi(g)) state, which is responsible for the luminescent properties of the uranyl ion. In neat methanol, because of stronger interaction between the excited triplet, T(1)((3)Phi(g)), state and the solvent via solvent to uranyl charge transfer, the U(VI) ion undergoes partial reduction to U(V) and the energy level of this state possibly lies lower than that of (UO(2)(2+))*, which is the transient species existing in aqueous solution, and hence increasing the energy gap between the T(2) and T(1) states in methanol solution. These facts possibly explain different spectral characteristics of the transient species produced in methanol and aqueous solutions as well as the longer lifetime of the IC process in methanol solution.

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Section: Resultsmentioning

confidence: 71%

Section: Resultsmentioning

confidence: 99%

Ultrafast Dynamics of the Excited States of the Uranyl Ion in Solutions

et al. 2010

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“…There have been a few studies on the complexation of U(VI) with nitrate in different ionic media [8][9][10][11][12][13][14][15][16], but the stability constants of U(VI)/nitrate complexes are very scattered. Besides, none of the studies were conducted at temperatures above 40°C [8][9][10][11][12][13][14][15][16].…”

Section: Introductionmentioning

confidence: 98%

“…Besides, none of the studies were conducted at temperatures above 40°C [8][9][10][11][12][13][14][15][16]. In this work, the stability constant of the 1:1 U(VI)/nitrate complex, UO 2 NO þ 3 , at temperatures from 25 to 70°C was determined by spectrophotometry and the enthalpy of complexation at 25°C was determined by microcalorimetry.…”

Section: Introductionmentioning

confidence: 99%