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91.
Reaction of UCl4 and excess Me3Sil in acetonitrile provides a convenient route to [Ul4(MeCN)4] (1), which was isolated in excellent yield and crystallized in acetonitrile as the ion pair complex [Ul2(MeCN)7][Ul6] (2). Compound 1 was transformed in pyridine (py) and dimethylformamide (dmf) into the Lewis base adducts [Ul4(py)3] (3) and [Ul4(dmf)6] (4). Crystals of 3 and [U(dmf)9]l4 (5) were obtained by slow diffusion of diethyl ether into pyridine or dmf solutions of 1; compound 5 is the first tetracationic {U4+} entity to have been crystallographically characterized. 相似文献
92.
Mehdoui T Berthet JC Thuéry P Ephritikhine M 《Chemical communications (Cambridge, England)》2005,(22):2860-2862
The capacity of NHC molecules to discriminate between trivalent lanthanide and actinide ions was revealed by competition reactions of analogous U(III) and Ce(III) compounds with C3Me4N2 and a comparison of the crystal structures of the corresponding carbene adducts. 相似文献
93.
Reactions of Ln(BH4)3(THF)3 (Ln = Nd, Ce) and M2dddt (M = Na, K; dddt = 5,6-dihydro-1,4-dithiine-2,3-dithiolate) in THF or pyridine gave, after addition of 18c6 (18-crown-6), several crystalline compounds which all contain the tris(dithiolene) Ln(dddt)3 unit. Crystals of [Na(18c6)(py)2]2[Na(18c6)(py)][Nd(dddt)3(py)].3py (1.3py) are built up from discrete mononuclear cationic and anionic species whereas crystals of {[Na(18c6)(py)2](0.5)[Na(18c6)(py)(1.5)][Na(1.5)Nd(dddt)3]}(infinity) (2) are composed of discrete [Na(18c6)(py)x]+ cations and polymeric anionic two-dimensional layers in which the Nd(dddt)3 units are linked to three neighbors by sodium atoms to form a honeycomb network. Analysis of the temperature dependence of the molar magnetic susceptibility of 2 shows that chiMT decreases from 1.63 cm3 K mol(-1) at 300 K down to 0.6 cm3 K mol(-1) at 5 K, due to the crystal-field splitting of the (4)I(9/2) free-ion state. Complexes {[Na3(18c6)(1.5)Nd(dddt)3(THF)].3THF}(infinity) (3.3THF) and {[K3(18c6)(1.5)Nd(dddt)3(py)].3py}(infinity) (4.3py) exhibit neutral polymeric layers with the Nd(dddt)3 units linked by M2(18c6) fragments. In the cerium compound {[Na2(18c6)Na(py)2Ce(dddt)3(py)].3py}(infinity) (5.3py), each Ce(dddt)3 unit is linked to two neighbors only by Na2(18c6) moieties, giving infinite zigzag chains. 相似文献
94.
Issam Oueslati Rym Abidi Zouhair Asfari Jacques Vicens Bernardo Masci Pierre Thuéry Martine Nierlich 《Journal of inclusion phenomena and macrocyclic chemistry》2001,39(3-4):353-355
The synthesis and X-ray crystalstructure of a novel tetrahomodioxacalix[6]arenehexamethylester 2 arepresented. Preliminary investigations of alkali metal ioncomplexation showed that 2 is apoor extractant with selectivity for lithium. 相似文献
95.
96.
K. A. Vokhmyanina P. N. Zhukova E. F. Irribarra A. S. Kubankin Le Thu Hoai R. M. Nazhmudinov N. N. Nasonov G. P. Pokhil 《Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques》2013,7(2):271-275
The effect of the contactless transmission (guiding) of 10 keV electrons through cylindrical dielectric channels and planar channels formed by glass plates is studied. The capture and propagation of an electron beam along the channel axis, usual in these cases, are observed in the experiments with two plates. The deviation of the reflection angle from the specular angle and its dependence on the plate length and beamcurrent value under beam reflection from a single plate are investigated. 相似文献
97.
98.
CO2 Conversion into Esters by Fluoride‐Mediated Carboxylation of Organosilanes and Halide Derivatives
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Dr. Pierre Thuéry Dr. Guillaume Lefèvre Dr. Thibault Cantat 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(9):2930-2934
A one‐step conversion of CO2 into heteroaromatic esters is presented under metal‐free conditions. Using fluoride anions as promoters for the C?Si bond activation, pyridyl, furanyl, and thienyl organosilanes are successfully carboxylated with CO2 in the presence of an electrophile. The mechanism of this unprecedented reaction has been elucidated based on experimental and computational results, which show a unique catalytic influence of CO2 in the C?Si bond activation of pyridylsilanes. The methodology is applied to 18 different esters, and it has enabled the incorporation of CO2 into a polyester material for the first time. 相似文献
99.
Ji-Young Bae Bon-Kyung Koo Han-Bong Ryu Jung-A Song Minh Tan Nguyen Thu Trang Thi Vu Young-Jin Son Hyang Kyu Lee Han Choe 《Applied biochemistry and biotechnology》2013,169(5):1633-1647
Extracellular superoxide dismutase (EC-SOD) is the only enzyme that removes superoxide radical in the extracellular space. The reduction of EC-SOD is linked to many diseases, suggesting that the protein may have therapeutic value. EC-SOD is reported to be insoluble and to make inclusion bodies when overexpressed in the cytoplasm of Escherichia coli. The refolding process has the advantage of high yield, but has the disadvantage of frequent aggregation or misfolding during purification. For the first time, this study shows that fusion with maltose-binding protein (MBP), N-utilization substance protein A, and protein disulfide isomerase enabled the soluble overexpression of EC-SOD in the cytoplasm of E. coli. MBP-tagged human EC-SOD (hEC-SOD) was purified by MBP affinity and anion exchange chromatography, and its identity was confirmed by MALDI-TOF MS analysis. The purified protein showed good enzyme activity in vitro; however, there was a difference in metal binding. When copper and zinc were incorporated into hEC-SOD before MBP tag cleavage, the enzymatic activity was higher than when the metal ions were bound to the purified protein after MBP tag cleavage. Therefore, the enzymatic activity of hEC-SOD is associated with metal incorporation and protein folding via disulfide bond. 相似文献
100.
A. G. Matveeva A. M. Thu A. M. Safiulina G. V. Bodrin E. I. Goryunov I. B. Goryunova O. A. Sinegribova E. E. Nifant’ev 《Russian Chemical Bulletin》2013,62(6):1309-1316
The extraction ability and selectivity of a series of phosphoryl ketones Ph2P(O)CH2C(O)Me, and Ph2P(O)CRR’CH2C(O)Me (R = H, Me; R’ = H, Me, n-C5H11, Ph, 2-thienyl, 2-furyl) towards trivalent lanthanides (LaIII, NdIII, HoIII, YbIII) and actinides (UVI, ThIV) were studied. The efficiency and selectivity of the new ligands in the extraction of f-elements from nitric acid solutions into chloroform were compared to those of model phosphine oxide Ph2P(O)Bu and known extractants: tributyl phosphate (BuO)3P(O), trioctylphosphine oxide (C8H17)3P(O), and carbamoylmethyl phosphine oxide Ph2P(O)CH2C(O)NBu2. 相似文献