Complexation of Uranium(VI) with Aromatic Acids in Aqueous Solution: A Combined Computational and Experimental Study

Wiebke, Jonas; Moritz, Anna; Glorius, Maja; Moll, Henry; Bernhard, Gert; Dolg, Michael

doi:10.1021/ic702162r

Cited by 17 publications

(40 citation statements)

References 68 publications

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“…However, if we calculate the sum of the charges on all the ligand atoms, it decreases from−1e − in free ligand to about−0.5e − in Np‐AHA complex. This observation is in contrast to that reported in U(VI)‐HA complexation where−0.8e charge is retained by ligand after complexation …”

Section: Resultscontrasting

confidence: 99%

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Coordination Modes of Hydroxamates in Neptunium (V) Complexes in Aqueous Solution

Dumpala

Rawat²,

Bhattacharya

et al. 2017

ChemistrySelect

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A theoretical study to understand molecular structures and coordination modes of neptunium complexes with three different substituent hydroxamates viz., acetohydroxamate (AHA), benzhydroxamate (BHA) and salicylhydroxamate (SHA) was carried out using density functional theory (DFT). The geometries for different complexes reported in literature M x L y H z (x:y:z) viz 1:1:1, 1:2:2 and 1:2:0 were optimized and interaction energies (DE) for complexation process were calculated to obtain the most probable structures of complexes. The DE value revealed, the complex stability order as NpO 2 + -SHA > NpO 2 -AHA > NpO 2 -BHA which is in agreement with the reported experimental data. Higher negative charge on AHA compared to BHA leads to its higher interaction with NpO 2 which in turn reflects in shorter Np-O eq (ligand) bond distances. In 1:1:1 complex of NpO 2 -SHA, the binding mode involving ortho hydroxyl group and -NHO À oxygen atom (seven membered ring) shows most negative interaction energy.However, for binding of second ligand in 1:2:2 NpO 2 -SHA complex, steric effects dominate and the mode involving five membered ring through oxygen atoms of -CONHO À is most stable.

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Section: Resultscontrasting

confidence: 99%

“…Wiebke et al. carried out Extended X‐ ray Absorption Fine Structure spectroscopic experiments and theoretical calculations to identify the coordinating atoms in U(VI)‐HA complexes in solution . Boulet et al.…”

Section: Introductionmentioning

confidence: 99%

Coordination Modes of Hydroxamates in Neptunium (V) Complexes in Aqueous Solution

Dumpala

Rawat²,

Bhattacharya

et al. 2017

ChemistrySelect

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“…In order to examine whether the tentative assignment of the species is realistic, time-dependent DFT (TD-DFT) calculations were performed. TD-DFT was previously applied on actinide complexes to study UV-vis absorption spectra 67 and X-ray absorption spectra. 68 , 69 …”

Section: Resultsmentioning

confidence: 99%

Combining luminescence spectroscopy, parallel factor analysis and quantum chemistry to reveal metal speciation – a case study of uranyl(vi) hydrolysis

et al. 2015

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“…They conclude that although the TD-DFT method does not provide accurate excitation energies, it leads in most cases to reasonable geometries, relaxation energies, and reactivity trends for uranyl(VI) complexes. Wiebke et al [29] applied TD-DFT method to calculate the absorption spectra of uranyl(VI) complexes.…”

Section: Xa C H T U N G T R E N N U N G (H 2 O)mentioning

confidence: 99%

Photoluminescence of Uranium(VI): Quenching Mechanism and Role of Uranium(V)

Tsushima¹,

Götz²,

Fahmy³

2010

Chemistry A European J

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The photoluminescence of uranium(VI) is observed typically in the wavelength range 400-650 nm with the lifetime of several hundreds mus and is known to be quenched in the presence of various halide ions (case A) or alcohols (case B). Here, we show by density functional theory (DFT) calculations that the quenching involves an intermediate triplet excited state that exhibits uranium(V) character. The DFT results are consistent with previous experimental findings suggesting the presence of photoexcited uranium(V) radical pair during the quenching process. In the ground state of uranyl(VI) halides, the ligand contributions to the highest occupied molecular orbitals increase with the atomic number (Z) of halide ion allowing larger ligand-to-metal charge transfer (LMCT) between uranium and the halide ion. Consequently, a larger quenching effect is expected as Z increases. The quenching mechanism is essentially the same in cases A and B, and is driven by an electron transfer from the quencher to the UO(2)(2+) entity. The relative energetic stabilities of the triplet excited state define the "fate" of uranium, so that in case A uranium(V) is oxidized back to uranium(VI), while in case B uranium remains as pentavalent.

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Complexation of Uranium(VI) with Aromatic Acids in Aqueous Solution: A Combined Computational and Experimental Study

Cited by 17 publications

References 68 publications

Coordination Modes of Hydroxamates in Neptunium (V) Complexes in Aqueous Solution

Coordination Modes of Hydroxamates in Neptunium (V) Complexes in Aqueous Solution

Combining luminescence spectroscopy, parallel factor analysis and quantum chemistry to reveal metal speciation – a case study of uranyl(vi) hydrolysis

Photoluminescence of Uranium(VI): Quenching Mechanism and Role of Uranium(V)

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