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排序方式: 共有227条查询结果,搜索用时 31 毫秒
21.
1,10‐Phenanthroline and Non‐Symmetrical 1,3,5‐Triazine Dipicolinamide‐Based Ligands For Group Actinide Extraction
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Dr. Julia Bisson Dr. Jérémy Dehaudt Dr. Marie‐Christine Charbonnel Dr. Denis Guillaneux Dr. Manuel Miguirditchian Dr. Cécile Marie Nathalie Boubals Guy Dutech Dr. Muriel Pipelier Dr. Virginie Blot Prof. Didier Dubreuil 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(25):7819-7829
The synthesis and evaluation of new extractants for spent nuclear fuel reprocessing are described. New bitopic ligands constituted of phenanthroline and 1,3,5‐triazine cores functionalized by picolinamide groups were designed. Synthetic routes were investigated and optimized to obtain twelve new polyaza‐heterocyclic ligands. In particular, an efficient and versatile methodology was developed to access non‐symmetric 2‐substituted‐4,6‐di(6‐picolin‐2‐yl)‐1,3,5‐triazines from the 1,3,5‐triazapentadiene precursor in the presence of anhydride reagents. Extraction studies showed the ability of both ligand series to extract and separate actinides selectively at different oxidation states (UVI, NpV,VI, AmIII, CmIII, and PuIV) from an acidic solution (3 M HNO3). Phenanthroline‐based ligands show the most promising efficiency for use in the group actinide extraction (GANEX) process due to a higher number of donor nitrogen atoms and a suitable pre‐organization of the dipicolinamide‐1,10‐phenanthroline architecture. 相似文献
22.
Thomas E. Albrecht-Schmitt David E. Hobart Dayan Páez-Hernández Cristian Celis-Barros 《International journal of quantum chemistry》2020,120(15):e26254
Experimental studies on the speciation of berkelium in carbonate media have shown that complexation of berkelium(III) by carbonate results in spontaneous oxidation to berkelium(IV) and that multiple species can be present in solution. We studied two proposed structures present in solution based on theoretical comparisons with spectroscopic data previously reported for Bk(IV) carbonate solutions. The multiconfigurational character of the ground and low-lying excited states in both complexes is demonstrated to result from the strong spin-orbit coupling. Although bonding in Bk(IV) carbonate and carbonate-hydroxide complexes is dominated by strong Coulombic forces, the presence of non-negligible covalent character is supported by ligand-field theory, natural localized orbitals, topological studies of the electron density, and energy transition state natural orbitals for chemical valence. Bond orders based on natural localized molecular orbitals show that Bk OH bonds possess enhanced orbital overlap, which is reflected in the bond strength. This is also observed in the decomposition of the orbital interaction energy into individual deformation density pairs. 相似文献
23.
Tianyu Yuan Shijie Xiong Xinghai Shen 《Angewandte Chemie (International ed. in English)》2020,59(40):17719-17725
The coordination of actinides and lanthanides, as well as strontium and cesium with graphdiyne (GDY) was studied experimentally and theoretically. On the basis of experimental results and/or theoretical calculations, it was suggested that Th4+, Pu4+, Am3+, Cm3+, and Cs+ exist in single‐ion states on the special triangular structure of GDY with various coordination patterns, wherein GDY itself is deformed in different ways. Both experiment and theoretical calculations strongly indicate that UO22+, La3+, Eu3+, Tm3+ and Sr2+ are not adsorbed by GDY at all. The distinguished adsorption behaviors of GDY afford an important strategy for highly selective separation of actinides and lanthanides, Th4+ and UO22+, and Cs+ and Sr2+, in the nuclear fuel cycle. Also, the present work sheds light on an approach to explore the unique functions and physicochemical properties of actinides in single‐ion states. 相似文献
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In the paper calculation of the moments of inertia for nuclei from the region 87 ≤ Z ≤ 100 and 130 ≤ N ≤ 156 was made in dependence on the angular momentum of their rotational states. The experimental values of the moments of
inertia were calculated for rotational energy of the classic rotor in its quantum form, with the use of a simple formula.
The moment of inertia term appearing in the formula was treated as a variable. The calculations were carried out on the basis
of experimental data for the energies of the rotational levels for 51 bands built on ground states for even-even nuclei and
for nuclei with odd mass number A. In addition, 30 rotational bands built on excited states were also analysed in the investigated region in case of even-even
nuclei. For many bands and nuclei the considered dependence of the moment of inertia on angular momentum has been found in
the analytical form by fitting polynomials to the experimental data. It turned out that obtained results for the moments of
inertia made it possible to describe the energies of rotational levels with a relative deviation not greater or only slightly
greater than 1%. In general, in the case of 12 bands of ground level the maximum relative deviation of obtained level energies
is smaller than 1%.
相似文献
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Various aspects of quantification in actinide research using photoelectron spectroscopy are discussed. In particular, the
influence of instrumental factors, different types of the background, and shape of the line intensities are addressed. We
give several examples of quantitative analysis of actinide bulk compounds and thin films. 相似文献
28.
William J. Evans Prof. Thomas J. Mueller Joseph W. Ziller Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(3):964-975
The limits of steric crowding in organometallic metallocene complexes have been examined by studying the synthesis of [(C5Me5)3MLn] complexes as a function of metal in which L=Me3CCN, Me3CNC, and Me3SiCN. The bis(tert‐butyl nitrile) complexes [(C5Me5)3Ln(NCCMe3)2] (Ln=La, 1 ; Ce, 2 ; Pr, 3 ) can be isolated with the largest lanthanide metal ions, La3+, Ce3+, and Pr3+. The Pr3+ ion also forms an isolable mono‐nitrile complex, [(C5Me5)3Pr(NCCMe3)] ( 4 ), whereas for Nd3+ only the mono‐adduct [(C5Me5)3Nd(NCCMe3)] ( 5 ) was observed. With smaller metal ions, Sm3+ and Y3+, insertion of Me3CCN into the M? C(C5Me5) bond was observed to form the cyclopentadiene‐substituted ketimide complexes [(C5Me5)2Ln{NC(C5Me5)(CMe3)}(NCCMe3)] (Ln=Sm, 6 ; Y, 7 ). With tert‐butyl isocyanide ligands, a bis‐isocyanide product can be isolated with lanthanum, [(C5Me5)3La(CNCMe3)2] ( 8 ), and a mono‐isocyanide product with neodymium, [(C5Me5)3Nd(CNCMe3)] ( 9 ). Silicon–carbon bond cleavage was observed in reactions between [(C5Me5)3Ln] complexes and trimethylsilyl cyanide, Me3SiCN, to produce the trimeric cyanide complexes [{(C5Me5)2Ln(μ‐CN)(NCSiMe3)}3] (Ln=La, 10 ; Pr, 11 ). With uranium, a mono‐nitrile reaction product, [(C5Me5)3U(NCCMe3)] ( 12 ), which is analogous to 5 , was obtained from the reaction between [(C5Me5)3U] and Me3CCN, but [(C5Me5)3U] reacts with Me3CNC through C? N bond cleavage to form a trimeric cyanide complex, [{(C5Me5)2U(μ‐CN)(CNCMe3)}3] ( 13 ). 相似文献
29.
30.
Christos Apostolidis Dr. Bernd Schimmelpfennig Dr. Nicola Magnani Dr. Patric Lindqvist‐Reis Dr. Olaf Walter Dr. Richard Sykora Dr. Alfred Morgenstern Dr. Eric Colineau Dr. Roberto Caciuffo Prof. Dr. Reinhardt Klenze Dr. Richard G. Haire Dr. Jean Rebizant Dr. Frank Bruchertseifer Dr. Thomas Fanghänel Prof. Dr. 《Angewandte Chemie (International ed. in English)》2010,49(36):6229-6229