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51.
Jean-Claude Berthet Jean-Francois Le Mar chal Michel Ephritikhine 《Journal of organometallic chemistry》1994,480(1-2):155-161
The monocyclooctatetraene uranium complex [U(COT)(I)2(THF)2] (COT=η-C8H8; THF=tetrahydrofuran), isolated from the reaction of bis(cyclooctatetraene)uranium with iodine, is a precursor for the synthesis of the alkyl derivatives [U(COT)(CH2Ph)2i (HMPA) 2], [U(COT)(CH2SiMe3)2(HMPA)] (HMPA=hexamethyl phosphorous triamide) and [U(COT)CH2SiMe3)3] [Li(THF)3] and of the mixed-ring compounds [U(COT)(η-C5R5)(I)] (R=H or Me). The last were used to prepare the amide and alkyl complexes [U(COT)(η-C5H5)(N{SiMe3}2)] and [U(COT)(η-C5Me5)(CH2SiMe3)]. 相似文献
52.
Cuccia LA Ruiz E Lehn JM Homo JC Schmutz M 《Chemistry (Weinheim an der Bergstrasse, Germany)》2002,8(15):3448-3457
The synthesis and characterization of an alternating pyridine-pyridazine strand comprising thirteen heterocycles are described. Spontaneous folding into a helical secondary structure is based on a general molecular self-organization process enforced by the conformational information encoded within the primary structure of the molecular strand itself. Conformational control based on heterocyclic "helicity codons" illustrates a strategy for designing folding properties into synthetic oligomers (foldamers). Strong intermolecular interactions of the highly ordered lock-washer subunits of compound 3 results in hierarchical supramolecular self-assembly into protofibrils and fibrils. Compound 3 also forms mechanically stable two-dimensional Langmuir-Blodgett and cast thin films. 相似文献
53.
Budimir N Fournier F Bailly T Burgada R Tabet JC 《Rapid communications in mass spectrometry : RCM》2005,19(13):1822-1828
The tripodal ligand N,N,N-tris[(1,hydroxy-2-pyridinon-6-yl)amide]propylamine was synthesized. It is composed of an anchor (nitrogen atom), a functional group (hydroxamate), and also a spacer of variable length defined by the number of methylene groups linking the anchor and the functional group. The characterization of this ligand in the presence of several divalent metal cations (Fe(II), Mn(II), Co(II) and Cu(II)), performed by electrospray ionization mass spectrometry (ESI-MS and ESI-MS/MS), allowed elucidation of oxidation states and also of different fragmentation patterns. The importance of the spacer length was studied in the case of the iron binary complex by comparing this ligand with another with a shorter spacer. In this way the stabilizing conditions, in which hydrogen bonds are implicated, were clarified. 相似文献
54.
Berthet JC Nierlich M Ephritikhine M 《Dalton transactions (Cambridge, England : 2003)》2004,(17):2814-2821
Dissolution of [UO2(OTf)2](1) in anhydrous thf, dme or py led to the formation of the complexes [UO2(OTf)2(thf)3](2), [UO2(OTf)2(dme)](3) and [UO2(OTf)2(py)3](4), respectively. Compounds 2 and 4 are neutral monomers in the solid state as well as the chloride [UO2Cl2(py)3](5) which was prepared in a similar way as for from the dimer [[UO2Cl2(thf)2]2]. Addition of 4 equivalents of triphenylphosphine oxide (tppo) to 1 afforded, in pyridine, the dicationic species [UO2(tppo)4][OTf]2 (6). The bi- or terdentate nitrogen molecules 2,2'-bipy, phen or terpy reacted with 1 in acetonitrile or pyridine to give [UO2(OTf)2(bipy)2](7), [UO2(phen)3][OTf]2(8), [UO2(OTf)2(terpy)](9) and [UO2(terpy)2][OTf]2(10), respectively. The hydroxide compound [[UO2(OH)(terpy)]2][OTf]2(11) was obtained by hydrolysis in air of 1 in a mixture of acetonitrile and ethanol in the presence of terpyridine. The X-ray crystal structures of , and reveal a novel coordination geometry for the uranyl ion, the uranium atom being in a rhombohedral environment; the six coordinating ligands atoms of the [UO2]2+ ion are separated into two parallel and staggered equilateral triangles and the UO2 axis is perpendicular to these triangles, passing through their centre. The structures of the mono(terpy) complexes 9 and 11 show the uranium atoms in a distorted pentagonal bipyramidal configuration with the nitrogen atom of the central pyridine ring of the terpy ligand significantly displaced from the equatorial plane. 相似文献
55.
Dr. Aurélien Adenot Dr. Lucile Anthore-Dalion Dr. Emmanuel Nicolas Jean-Claude Berthet Dr. Pierre Thuéry Dr. Thibault Cantat 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(72):18047-18053
An air-tolerant Cu-catalyzed sulfonylative Hiyama cross-coupling reaction enabling the formation of diaryl sulfones is described. Starting from aryl silanes, DABSO and aryliodides, the reaction tolerates a large variety of polar functional groups (amines, ketones, esters, aldehydes). Control experiments coupled with DFT calculations shed light on the mechanism, characterized by the formation of a Cu(I)-sulfinate intermediate via fast insertion of a SO2 molecule. 相似文献
56.
Manqi Ruan Hang Zhao Gang Li Chengdong Fu Zhigang Wang Xinchou Lou Dan Yu Vincent Boudry Henri Videau Vladislav Balagura Jean-Claude Brient Peizhu Lai Chia-Ming Kuo Bo Liu Fenfen An Chunhui Chen Soeren Prell Bo Li Imad Laketineh 《The European Physical Journal C - Particles and Fields》2018,78(5):426
After the Higgs discovery, precise measurements of the Higgs properties and the electroweak observables become vital for the experimental particle physics. A powerful Higgs/Z factory, the Circular Electron Positron Collider (CEPC) is proposed. The Particle Flow oriented detector design is proposed to the CEPC and a Particle Flow algorithm, Arbor is optimized accordingly. We summarize the physics object reconstruction performance of the Particle Flow oriented detector design with Arbor algorithm and conclude that this combination fulfills the physics requirement of CEPC. 相似文献
57.
Huy Loc Nguyen James Dedier Jean-Claude Rouillon Gilles Sigaud 《Liquid crystals》2013,40(11):1637-1644
The synthesis of two series of semiperfluoroalkyloxyphenyl and perfluoroalkylphenyl β-D-glucopyranosides is described. Their mesomorphic properties are studied by DSC, polarized optical microscopy and X-ray diffraction. All mesophases are identified as smectic A with a bimolecular in-layer arrangement. 相似文献
58.
Josette Olivier-Fourcade Costana Mihaela Ionica-Bousquet Pierre-Emmanuel Lippens Jean-Claude Jumas 《Hyperfine Interactions》2012,207(1-3):33-36
Due to their high storage capacity Sn-based materials are of considerable interest as negative electrode for Li-ion batteries. However the strong volume change occurring during the alloy formation strongly limits the electrochemical performances (cycle and time life). Analysis by M?ssbauer spectroscopy using model compounds (Sn, Sn-Li and transition metal-Sn alloys) shows that the volume expansion is related to the structural change from a Sn based network to a Li based network. Two types of materials are proposed here to overcome this problem: tin dispersion in an electrochemically inactive oxide matrix with buffer role to absorb volume changes or tin alloying with an inactive transition metal to minimize the volume expansion. The use of M?ssbauer spectroscopy (in situ operando mode) allows a dynamic approach which is essential to understand the fundamental causes of ageing on cycling and to define then the key issues to be solved for material’s application. 相似文献
59.
Nuclear Overhauser effects allow us to determine all transition probabilities in a two-spin AB system, using a triple resonance apparatus we have constructed. Theoretical and experimental studies of the relaxation in the special case where the nuclei belong to a molecule interconverting slowly between two different conformations have been made, and the exchange ratio has been deduced. 相似文献
60.
A two-stage low-temperature solution polycondensation process is described for the synthesis of two kinds of block copolyamides: poly(p-biphenylene terephtalamide-co-adipamide) and poly(2,5-dimethyl trans-piperazine terephthalamide-co-adipamide). The reactivity of oligomeric end groups in various solvents is examined. This study ascertains the influence of the nature of the solvent on the extent of polycondensation. End groups seem to be more reactive in a medium in which the polyamide is soluble; this property is used for the synthesis of block copolycondensates. 相似文献