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The interactions of dopamine [2-(3,4-Dihydroxyphenyl)ethylamine, (Dop - )] with cadmium(II), copper(II) and uranyl(VI) were studied in NaCl(aq) at different ionic strengths (0 ≤ I /mol dm -3 ≤ 1.0) and temperatures (288.15 ≤ T /K ≤ 318.15). From the elaboration of the experimental data, it was found that the speciation models are featured by species of different stoichiometry and stability. In particular for cadmium, the formation of only MLH, ML and ML 2 (M = Cd 2+ ; L = dopamine) species was obtained. For uranyl(VI) (UO 2 2+ ), the speciation scheme is influenced by the use of UO 2 (acetate) 2 salt as a chemical; in this case, the formation of ML 2 , MLOH and the ternary MLAc (Ac = acetate) species in a wide pH range was observed. The most complex speciation model was obtained for the interaction of Cu 2+ with dopamine; in this case we observed the formation of the following species: ML 2 , M 2 L, M 2 L 2 , M 2 L 2 (OH) 2 , M 2 LOH and ML 2 OH. These speciation models were determined at each ionic strength and temperature investigated. As a further contribution to this kind of investigation, the ternary interactions of dopamine with UO 2 2+ /Cd 2+ and UO 2 2+ /Cu 2+ were investigated at I = 0.15 mol dm -3 and T = 298.15K. These systems have different speciation models, with the MM'L and M 2 M'L 2 OH [M = UO 2 2+ ; M' = Cd 2+ or Cu 2+ , L = dopamine] common species; the species of the mixed Cd 2+ containing system have a higher stability with respect the Cu 2+ containing one. The dependence on the ionic strength of complex formation constants was modelled by using both an extended Debye-Hückel equation that included the Van't Hoff term for the calculation of the formation enthalpy change values and the Specific Ion Interaction Theory (SIT). The results highlighted that, in general, the entropy is the driving force of the process. The quantification of the effective sequestering ability of dopamine towards the studied cations was evaluated by using a Boltzmann-type equation and the calculation of pL 0.5 parameter. The sequestering ability was quantified at different ionic strengths, temperatures and pHs, and this resulted, in general, that the pL 0.5 trend was always: UO 2 2+ > Cu 2+ > Cd 2+ .

Cytochrome c3 (uranyl reductase) from Desulfovibrio vulgaris can reduce uranium in bacterial cells and in cell-free systems. This gene was introduced in tobacco under control of the RbcS promoter, and the resulting transgenic plants accumulated uranium when grown on a uranyl ion containing medium. The uptaken uranium was detected by EM in chloroplasts. In the presence of uranyl ions in sublethal concentration, the transgenic plants grew phenotypically normal while the control plants' development was impaired. The data on uranium oxidation state in the transgenic plants and the possible uses of uranium hyperaccumulation by plants for environmental cleanup are discussed.

Three novel 2-aminopyrazine Schiff bases derived from salicylaldehyde derivatives and their uranyl complexes were synthesized and characterized by elemental analysis, UV-vis, FTIR, molar conductance, and thermal gravimetric analysis (TGA). The proposed structures were optimized using density functional theory (DFT/B3LYP) and 6-311G ∗(d,p) basis sets. All uranyl complexes are soluble in DMSO and have low molar conductance, which indicates that all the complexes are nonelectrolytes. The DNA binding of those Schiff bases and their uranyl complexes was studied using UV-vis spectroscopy, and screening of their ability to bind to calf thymus DNA (CT-DNA) showed that the complexes interact with CT-DNA through an intercalation mode, for which the K b values ranged from 1 × 10 6 to 3.33 × 10 5 M -1 . The anticancer activities of the Schiff base ligands and their uranyl complexes against two ovarian (Ovcar-3) and melanoma cell lines (M14) were investigated, and the results indicated that uranyl complexes exhibit better results than the Schiff base ligands. Molecular docking identified the distance, energy account, type, and position of links contributing to the interactions between these complexes and two different cancer proteins (3W2S and 2OPZ).

EXAFS spectroscopy is one of the most used techniques to solve the structure of actinoid solutions. In this work a systematic analysis of the EXAFS spectra of four actinyl cations, [UO 2 ] 2+ , [NpO 2 ] 2+ , [NpO 2 ] + and [PuO 2 ] 2+ has been carried out by comparing experimental results with theoretical spectra. These were obtained by averaging individual contributions from snapshots taken from classical Molecular Dynamics simulations which employed a recently developed [AnO 2 ] 2+/+ -H 2 O force field based on the hydrated ion model using a quantum-mechanical (B3LYP) potential energy surface. Analysis of the complex EXAFS signal shows that both An-Oyl and An-OW single scattering paths as well as multiple scattering ones involving [AnO 2 ] +/2+ molecular cation and first-shell water molecules are mixed up all together to produce a very complex signal. Simulated EXAFS from the B3LYP force field are in reasonable agreement for some of the cases studied, although the k = 6-8 Å-1 region is hard to be reproduced theoretically. Except uranyl, all studied actinyls are open-shell electron configurations, therefore it has been investigated how simulated EXAFS spectra are affected by minute changes of An-O bond distances produced by the inclusion of static and dynamic electron correlation in the quantum mechanical calculations. A [NpO 2 ] + -H 2 O force field based on a NEVPT2 potential energy surface has been developed. The small structural changes incorporated by the electron correlation on the actinyl aqua ion geometry, typically smaller than 0.07 Å, leads to improve the simulated spectrum with respect to that obtained from the B3LYP force field. For the other open-shell actinyls, [NpO 2 ] 2+ and [PuO 2 ] 2+ , a simplified strategy has been adopted to improve the simulated EXAFS spectrum. It is computed taking as reference structure the NEVPT2 optimized geometry and including the DW factors of their corresponding MD simulations employing the B3LYP force field. A better agreement between the experimental and the simulated EXAFS spectra is found, confirming the a priori guess that the inclusion of dynamic and static correlation refine the structural description of the open-shell actinyl aqua ions.

The widespread use of uranium for civilian purposes causes a worldwide concern of its threat to human health due to the long-lived radioactivity of uranium and the high toxicity of uranyl ion (UO 2 2+ ). Although uranyl-protein/DNA interactions have been known for decades, fewer advances are made in understanding their structural-functional impacts. Instead of focusing only on the structural information, this article aims to review the recent advances in understanding the binding of uranyl to proteins in either potential, native, or artificial metal-binding sites, and the structural-functional impacts of uranyl-protein interactions, such as inducing conformational changes and disrupting protein-protein/DNA/ligand interactions. Photo-induced protein/DNA cleavages, as well as other impacts, are also highlighted. These advances shed light on the structure-function relationship of proteins, especially for metalloproteins, as impacted by uranyl-protein interactions. It is desired to seek approaches for biological remediation of uranyl ions, and ultimately make a full use of the double-edged sword of uranium.

The Schiff base hydrazone ligand HL was prepared by the condensation reaction of 7-chloro-4-quinoline with o-hydroxyacetophenone. The ligand behaves either as monobasic bidentate or dibasic tridentate and contain ONN coordination sites. This was accounted for be the presence in the ligand of a phenolic azomethine and imine groups. It reacts with Cu(II), Ni(II), Co(II), Mn(II), UO(2) (VI) and Fe(II) to form either mono- or binuclear complexes. The ligand and its metal complexes were characterized by elemental analyses, IR, NMR, Mass, and UV-Visible spectra. The magnetic moments and electrical conductance of the complexes were also determined. The Co(II), Ni(II) and UO(2) (VI) complexes are mononuclear and coordinated to NO sites of two ligand molecules. The Cu(II) complex has a square-planar geometry distorted towards tetrahedral, the Ni(II) complex is octahedral while the UO(2) (VI) complex has its favoured heptacoordination. The Co(II), Mn(II) complexes and also other Ni(II) and Fe(III) complexes, which were obtained in the presence of Li(OH) as deprotonating agent, are binuclear and coordinated via the NNNO sites of two ligand molecules. All the binuclear complexes have octahedral geometries and their magnetic moments are quite low compared to the calculated value for two metal ions complexes and thus antiferromagnetic interactions between the two adjacent metal ions. The ligand HL and metal complexes were tested against a strain of Gram +ve bacteria (Staphylococcus aureus), Gram -ve bacteria (Escherichia coli), and fungi (Candida albicans). The tested compounds exhibited high antibacterial activities.

Canister integrity and radionuclides retention is of prime importance for assessing the long term safety of nuclear waste stored in engineered geologic depositories. A comparative investigation of the interaction of uranyl ion with three different mineral surfaces has thus been undertaken in order to point out the influence of surface composition on the adsorption mechanism(s). Periodic DFT calculations using plane waves basis sets with the GGA formalism were performed on the TiO(2)(110), Al(OH)(3)(001) and Ni(111) surfaces. This study has clearly shown that three parameters play an important role in the uranyl adsorption mechanism: the solvent (H(2)O) distribution at the interface, the nature of the adsorption site and finally, the surface atoms' protonation state.