The enhanced uranyl–amidoxime binding by the electron-donating substituents

Qin, Zhen; Ren, Yiming; Shi, Siwei; Yang, Chu‐Ting; Yu, Jie; Wang, Shaofei; Jia, Jianping; Yu, Haizhu; Wang, Xiaolin

doi:10.1039/c7ra00404d

Cited by 9 publications

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References 25 publications

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“…Firstly, due to the high affinity towards uranyl ions in a chelating coordination mode, amidoxime (AO) has been identified as one of the most effective ligands of uranium. [51][52][53][54] A considerable number of AO-containing adsorbent materials, especially those with polymer matrixes, have been developed for UES. 25 The most studied AO-based polymers are generally prepared by grafting acrylonitrile (AN) monomers onto polyolefin supports with robust backbones, such as polyethylene (PE) and polypropylene (PP) (Fig.…”

Section: Strategies For Improving the Adsorption Abilitymentioning

confidence: 99%

Uranium extraction from seawater: material design, emerging technologies and marine engineering

et al. 2023

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Section: Strategies For Improving the Adsorption Abilitymentioning

confidence: 99%

Uranium extraction from seawater: material design, emerging technologies and marine engineering

et al. 2023

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“…The first binding motif displays both acetamidoxime and benzamidoxime molecules with an η 1 -O binding through the oxygen atom in the oxime functional group . The second binding motif involves side-on η 2 binding through the N–O bond of the amidoxime functionality, which was shown to be the most stable binding by density functional theory. − A third binding motif was recently reported with the first dinuclear AO–uranyl complex, where the uranyl metal centers were bridged by two zwitterionic benzamidoxime molecules through the μ 2 -O atom of the oxime . While the reported AO–uranyl structures are good references for possible binding motifs, they are not representative of the AO–uranyl complexes on the surface of AO-PAN mat,s where there is a prevalence of hydrolysis effects and high amidoxime to uranyl molar ratios, causing considerable amounts of amorphous precipitation on the surface of the AO-PAN mat during uranyl uptake experiments.…”

Section: Introductionmentioning

confidence: 99%

Uranyl Speciation on the Surface of Amidoximated Polyacrylonitrile Mats

et al. 2020

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Naturally occurring uranium is a widespread contaminant present in the water resources around the abandoned uranium mines in the southwest United States. A novel method for rapid uranium detection has been recently developed that relies on the sequestering of uranium by amidoximated polyacrylonitrile (AO-PAN) polymer mats and uses the Raman-active (ν1) symmetric stretch as the signal. The Raman signals obtained from uranium bearing AO-PAN were challenging to interpret due to an unknown uranyl speciation on the surface of the mats. Herein, we provide the synthesis and structural characterization of six model coordination compounds that contain acetamidoxime/benzamidoxime (AAO/BAO) coordinated to the uranyl cation: [UO2(η1-AAO)(NO3)2(H2O)] (1), [UO2(η1-AAO)2(NO3)2] (2), [UO2(η2-BAO)2(CH3OH)2] (3), [(UO2)3(η2-BAO)3(μ2-NO3)3] (4), [(UO2)4(μ3-O)2(μ2-BAO)4(η1-BAO)4(H2O)2](NO3)4 (5), and [(UO2)4(μ3-O)2(μ2-BAO)4(η1-BAO)6Na(NO3)2](NO3)3 (6). Solid-state Raman spectra of 1–6 showed dramatic differences in the uranyl ν1 symmetric stretch depending on the coordination of the amidoxime functional group. The assignments made from the solid-state Raman spectra were used to deconvolute the solution-state Raman spectra of uranyl–acetamidoxime/benzamidoxime methanol solutions at different metal to ligand molar ratios. At low molar ratios (1 U:1 AAO/BAO and 1 U:2 AAO/BAO) the dominant species is the uranyl coordinated via the η1-oxygen atom of the oxime group, while at high molar ratios (1 U:3 AAO/BAO and 1 U:4 AAO/BAO) the dominant species are a tetrameric uranyl−μ3-O-η1-amidoxime complex similar to compounds 5 and 6 and a uranyl−η2-amidoxime complex similar to compounds 3 and 4. Solid-state Raman spectra showed good agreement with Raman signals obtained from the uranyl–AO-PAN mats, demonstrating that binding motifs between uranyl and amidoxime in compounds 5 and 6 are the most representative of the uranyl species on the surface of the AO-PAN mats.

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“…The technological implications of the structures, with respect to the selective extraction of uranium from seawater using amidoxime-based sorbents, will be outlined. Solution [10][11][12] and theoretical [13][14][15][16][17] reports on this general topic are very limited. Thus, apologies are due to the researchers whose excellent work will not be mentioned here.…”

Section: Introduction-scope and Organization Of This Reviewmentioning

confidence: 99%

Synthetic and Structural Chemistry of Uranyl-Amidoxime Complexes: Technological Implications

et al. 2023

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Resource shortage is a major problem in our world. Nuclear energy is a green energy and because of this and its high energy density, it has been attracting more and more attention during the last few decades. Uranium is a valuable nuclear fuel used in the majority of nuclear power plants. More than one thousand times more uranium exists in the oceans, at very low concentrations, than is present in terrestrial ores. As the demand for nuclear power generation increases year-on-year, access to this reserve is of paramount importance for energy security. Water-insoluble polymeric materials functionalized with the amidoxime group are a technically feasible platform for extracting uranium, in the form of {UO2}2+, from seawater, which also contains various concentrations of other competing metal ions, including vanadium (V). An in-depth understanding of the coordination modes and binding strength of the amidoxime group with uranyl and other competing ions is a key parameter for improving extraction efficiency and selectivity. Very limited information on the complexation of {UO2}2+ with amidoximes was available before 2012. However, significant advances have been made during the last decade. This report reviews the solid-state coordination chemistry of the amidoxime group (alone or within ligands with other potential donor sites) with the uranyl ion, while sporadic attention on solution and theoretical studies is also given. Comparative studies with vanadium complexation are also briefly described. Eight different coordination modes of the neutral and singly deprotonated amidoxime groups have been identified in the structures of the uranyl complexes. Particular emphasis is given to describing the reactivity of the open-chain glutardiamidoxime, closed-ring glutarimidedioxime and closed-ring glutarimidoxioxime moieties, which are present as side chains on the sorbents, towards the uranyl moiety. The technological implications of some of the observed coordination modes are outlined. It is believed that X-ray crystallography of small uranyl-amidoxime molecules may help to build an understanding of the interactions of seawater uranyl with amidoxime-functionalized polymers and improve their recovery capacity and selectivity, leading to more efficient extractants. The challenges for scientists working on the structural elucidation of uranyl coordination complexes are also outlined. The review contains six sections and 95 references.

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The enhanced uranyl–amidoxime binding by the electron-donating substituents

Abstract: This work describes the enhanced binding between uranyl and amidoxime ligands due to the electron-donating effect of the substituents.

Cited by 9 publications

References 25 publications

Uranium extraction from seawater: material design, emerging technologies and marine engineering

Uranium extraction from seawater: material design, emerging technologies and marine engineering

Uranyl Speciation on the Surface of Amidoximated Polyacrylonitrile Mats

Synthetic and Structural Chemistry of Uranyl-Amidoxime Complexes: Technological Implications

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