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511.
Gev Dovrat Marie-Claire Illy Dr. Claude Berthon Ana Lerner Prof. Dr. Moshe H. Mintz Dr. Eric Maimon Dr. Radion Vainer Dr. Yeshayahu Ben-Eliyahu Yulia Moiseev Prof. Dr. Philippe Moisy Prof. Dr. Armand Bettelheim Prof. Dr. Israel Zilbermann 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(15):3390-3403
The 1,4,7,10-tetrazacyclodecane-1,4,7,10-tetraacetic acid (DOTA) aqueous complex of UIV with H2O, OH−, and F− as axial ligands was studied by using UV/Vis spectrophotometry, ESI-MS, NMR spectroscopy, X-ray crystallography, and electrochemistry. The UIV–DOTA complex with either water or fluoride as axial ligands was found to be inert to oxidation by molecular oxygen, whereas the complex with hydroxide as an axial ligand slowly hydrolyzed and was oxidized by dioxygen to a diuranate precipitate. The combined data set acquired shows that, although axial substitution of fluoride and hydroxide ligands instead of water does not seem to significantly change the aqueous DOTA complex structure, it has an important effect on the electronic configuration of the complex. The UIV/UIII redox couple was found to be quasi-reversible for the complex with both axially bonded H2O and hydroxide, but irreversible for the complex with axially bonded fluoride. Intriguingly, binding of the axial fluoride renders the irreversible one-electron UV/UIV oxidation of the [UIV(DOTA)(H2O)] complex quasi-reversible, which suggests the formation of the short-lived pentavalent form of the complex, an aqueous non-uranyl chelated UV cation. 相似文献
512.
Igor Nikovskiy Dr. Alexander Polezhaev Prof. Valentin Novikov Dmitry Aleshin Dr. Alexander Pavlov Elnara Saffiulina Dr. Rinat Aysin Dr. Pavel Dorovatovskii Lydia Nodaraki Prof. Floriana Tuna Prof. Yulia Nelyubina 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(25):5629-5638
The molecular design of spin-crossover complexes relies on controlling the spin state of a transition metal ion by proper chemical modifications of the ligands. Herein, the first N,N’-disubstituted 2,6-bis(pyrazol-3-yl)pyridines (3-bpp) are reported that, against the common wisdom, induce a spin-crossover in otherwise high-spin iron(II) complexes by increasing the steric demand of a bulky substituent, an ortho-functionalized phenyl group. As N,N’-disubstituted 3-bpp complexes have no pendant NH groups that make their spin state extremely sensitive to the environment, the proposed ligand design, which may be applicable to isomeric 1-bpp or other families of popular bi-, tri- and higher denticity ligands, opens the way for their molecular design as spin-crossover compounds for future breakthrough applications. 相似文献
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515.
Journal of Solid State Electrochemistry - 相似文献
516.
T. A. Gracheva T. A. Kuz’micheva V. N. Perevezentsev A. E. Mochalova L. A. Smirnova E. V. Salomatina 《Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques》2011,5(3):426-430
The kinetics of UV-induced formation of gold nanoparticles in polymethylmethacrylate films doped with chloroauric acid HAuCl4 is studied. The films are investigated by the absorption spectroscopy and smallangle X-ray scattering methods. The changing size and polydispersity of gold nanoparticles are analyzed during their formation. The growth of gold nanoparticles is determined by the properties of a polymeric matrix and the rate of diffusion fluxes of matter. 相似文献
517.
Synthesis of water dispersible boron core silica shell (B@SiO<Subscript>2</Subscript>) nanoparticles
Nathan I. Walton Zhe Gao Yulia Eygeris Hamidreza Ghandehari Ilya Zharov 《Journal of nanoparticle research》2018,20(4):112
Water dispersible boron nanoparticles have great potential as materials for boron neutron capture therapy of cancer and magnetic resonance imaging, if they are prepared on a large scale with uniform size and shape and hydrophilic modifiable surface. We report the first method to prepare spherical, monodisperse, water dispersible boron core silica shell nanoparticles (B@SiO2 NPs) suitable for aforementioned biomedical applications. In this method, 40 nm elemental boron nanoparticles, easily prepared by mechanical milling and carrying 10-undecenoic acid surface ligands, are hydrosilylated using triethoxysilane, followed by base-catalyzed hydrolysis of tetraethoxysilane, which forms a 10-nm silica shell around the boron core. This simple two-step process converts irregularly shaped hydrophobic boron particles into the spherically shaped uniform nanoparticles. The B@SiO2 NPs are dispersible in water and the silica shell surface can be modified with primary amines that allow for the attachment of a fluorophore and, potentially, of targeting moieties. 相似文献
518.
Borchert H Borchert Y Kaichev VV Prosvirin IP Alikina GM Lukashevich AI Zaikovskii VI Moroz EM Paukshtis EA Bukhtiyarov VI Sadykov VA 《The journal of physical chemistry. B》2005,109(43):20077-20086
Nanostructured ceria doped with other rare earth elements is a good oxygen ion conductor, which gives rise to various catalytic applications such as the construction of membranes for syngas production by partial oxidation of methane. This article focuses on the Gd-doped cerium dioxides, which can be modified with Pt or Pd to enhance the reactivity of the lattice oxygen in interaction with methane. The aim of the work is the elucidation of correlations between the structural, electronic, and chemical properties of these nanomaterials. Detailed studies were performed for a series of samples with and without surface modification by noble metals using a complex combination of physicochemical methods: XRD, TEM, CH(4) TPR, XPS, SIMS, and FTIR spectroscopy of adsorbed CO. XPS and TPR data revealed that surface modification with noble metals enhances the reducibility of the doped ceria support, where the effect is more pronounced for Pd than for Pt. The formation of highly cationic Pd species due to strong metal support interactions provides a possible explanation for this behavior. Furthermore, the results obtained in the present work for the Gd-doped ceria system are compared to those obtained previously for the Pr-doped ceria system. 相似文献
519.
The goal is to investigate spectral properties of the operator H=(–i +a(x))2+a0(x) in the two-dimensional situation, a(x), a0(x)) being periodic. We construct asymptotic formulae for Bloch eigenvalues and eigenfunctions in the high-energy region, describe properties of isoenergetic curves in the space of quasimomenta and give a new proof of the Bethe-Sommerfeld conjecture.Research partially supported by USNSF Grant DMS-0201383.Acknowledgements The author is thankful to Konstantin Makarov for very useful discussions and to Young-Ran Lee for her great help with pictures. 相似文献
520.
Melnikov A.V. Tarasyan K.N. Vershkov V.A. Dreval V.A. Sushkov A.A. Lysenko S.E. Sannikov V.V. Gorshkov A.V. Krupnik L.I. Nedzelskij I.S. Kharchev N.K. Fomin G.A. Mochalova L.A. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》1994,22(4):363-368
The HIBP method was used in the experiments on the T-10 tokamak to measure the space potential distribution as a function of gas feed. A high electric field was observed in the region where the ionization of neutrals takes place. The correlation of the potential with the gas flux dynamics and the MHD activity was also found 相似文献