Kinetic Behavior of Carbonate Ligands with Different Coordination Modes: Equilibrium Dynamics for Uranyl(2+) Carbonato Complexes in Aqueous Solution. A 13C and 17O NMR Study

Bányai, István; Glaser, Julius; Micskei, Károly; Tóth, I.; Zékány, László

doi:10.1021/ic00118a028

Cited by 48 publications

(60 citation statements)

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“…The chemical shifts of HCO 3 À and CO 3 2À are 173 and 191 ppm, respectively; theses values are similar to those obtained by Banyai et al [9], who found 172 and 189 ppm, respectively. A mixture HCO 3 À /CO 3 2À displays only one peak due to the fast proton exchange between both species.…”

supporting

confidence: 90%

“…Thus, the extent of carbonate complexation rises with the increase of the concentration of HCO 3 À in the initial solution. Our results can be easily compared to the behavior of [(UO 2 ) 3 (CO 3 ) 6 ] 6À [9], which showed only one broad peak at 215 ppm in its 17 O-NMR spectrum for its three bridging and three bidentate carbonato ligands. In Zr 4 , as well as in uranyl complexes, the broadness of the peak of coordinated carbonate ions may be due to quadrupolar relaxation and/or to a fast exchange process.…”

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confidence: 86%

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Aqueous Chemistry of Zirconium(IV) in Carbonate Media

Veyland

Dupont

Rimbault

et al. 2000

HCA

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The interactions between carbonate ions and zirconium oxychloride are studied by potentiometry, dialysis, and 13C‐ and 17O‐NMR spectroscopy in aqueous media. The nature of the soluble carbonatohydroxo complexes depends on the proportions of hydrogencarbonate and carbonate ions in solution before the addition of zirconium oxychloride. Carbonate media lead to polynuclear entities containing no more than two complexed carbonate ions per Zr4+. The presence of hydrogencarbonate favors the formation of less condensed and more carbonated complexes such as [Zr(CO3)4]4−. The polycondensation degree of the species decreases when the number of carbonates linked per Zr4+ increases. In all complexes, the carbonate is bidentate, and the metal atoms are linked via hydroxo bridges. The complexation of carbonate with Zr4+ occurs for a total carbonate concentration higher than 0.1M. Consequently, in natural medium, the speciation of this metal is governed only by the formation of hydroxo complexes.

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confidence: 90%

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confidence: 86%

Aqueous Chemistry of Zirconium(IV) in Carbonate Media

Veyland

Dupont

Rimbault

et al. 2000

HCA

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“…A resonance at $1135 ppm was suggested to originate from a minor species. However, the authors were not able to reproduce [561] the previous spectrum [560] which was probably due to sample decomposition resulting in a mixture of hydroxo-carbonato uranyl complexes. Reinvestigation [561] of the equilibrium dynamics of uranyl(2+) carbonato complexes in aqueous solution by the use of 17 O and 13 C NMR provided an independent confirmation of the structure in Fig.…”

Section: Oxygen Bonded To Transition Metal Elementsmentioning

confidence: 94%

Oxygen-17 NMR spectroscopy: Basic principles and applications (Part I)

Gerothanassis

2010

Progress in Nuclear Magnetic Resonance Spectroscopy

122

107

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“…The difference of pH between the various solutions is at most 0. [16] noticed a clear correlation between the kinetic behavior and the coordination mode of the carbonato ligands. Only dynamic NMR studies allow examination of the actual reaction mechanism in solution.…”

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confidence: 90%

“…According to van Eldik [20], an associative mechanism would lead to a reaction intermediate with an increased coordination number, i. e., in the present case to [Zr( CO 3 ) 5 ] 6À . Unfortunately, the signs of thermodynamical data, such as the activation entropy and the activation volume of the reaction, which are very useful to determine the mechanism type [20], cannot be determined for the [Zr(CO 3 [16].…”

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confidence: 99%