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11.
N. G. Naumov K. A. Brylev S. Cordier O. Hernandez C. Perrin V. E. Fedorov 《Journal of Structural Chemistry》2003,44(4):698-703
Two new compounds containing molybdenum thiocyanide cluster anions, K6[Mo4S4(CN)12]·10H2O (1) and (18-crown-6K)8[Mo6S6(CN)16]·17.5H2O (2), were synthesized and investigated by X-ray structure analysis. Crystal data: a=11.8430(17), b=11.8430(17), c=35.170(7) , V=4932.8(14) 3, space group I41/a, Z=4, dcalc=1.563 g/cm3 for 1; a=28.7513(5), b=18.4190(3), c=20.7586(4) , =118.5982(7)°, V=9651.9(3) 3, space group C2/m, Z=4, dcalc =1.563 g/cm3 for 2. The [Mo4S4(CN)12]6- cluster anion in 1 has an ordinary structure typical of cubane transition metal complexes. In the structure of the [Mo6S6(CN)16]8- anion of 2, two crystallographically independent molybdenum atoms form a Mo6 metallocluster, represented as two edge-sharing tetrahedra. 相似文献
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Two new series of Nb6 bromides, CsRENb6Br18 (RE = all the lanthanides excepted Eu and Yb, + Y) (type H ) and M2RENb6Br18 (M = Cs, Rb, Tl; RE = Eu, Yb) (type R ) have been isolated. The crystal structures of CsErNb6Br18 and Cs2EuNb6Br18, isotypic with the corresponding chlorides, have been determined by single crystal X-ray diffraction data. The (Nb6Br18) intra-unit strength is related to the nature and the charge of the counter cation. A comparison between the corresponding chlorides and bromides series, based on the chemical properties and the size of the halogen is discussed. 相似文献
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Dr. Wei Zhang Dr. Emmanuel Baudouin Marie Cordier Dr. Gilles Frison Dr. Bastien Nay 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(36):8643-8648
A one-pot methodology to synthesize metastable bicyclic 2,5-dihydrooxepines from cyclic 1,3-diketones and 1,4-dibromo-2-butenes through the retro-Claisen rearrangement of syn-2-vinylcyclopropyl diketone intermediates is reported. DFT calculations were performed to understand the reaction selectivity and mechanisms towards [1,3]- or [3,3]-sigmatropic rearrangements, highlighting the crucial influence of the temperature. The reaction was successfully applied to a short protecting group-free total synthesis of radulanin A, a natural 2,5-dihydrobenzoxepine. Moreover, the strong herbicidal potential of this natural product is demonstrated for the first time. 相似文献
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Erwann Le Coz Joanna Hammoud Dr. Thierry Roisnel Marie Cordier Dr. Vincent Dorcet Dr. Samia Kahlal Prof. Dr. Jean-François Carpentier Prof. Dr. Jean-Yves Saillard Dr. Yann Sarazin 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(46):11966-11982
Barium complexes ligated by bulky boryloxides [OBR2]− (where R=CH(SiMe3)2, 2,4,6-iPr3-C6H2 or 2,4,6-(CF3)3-C6H2), siloxide [OSi(SiMe3)3]−, and/or phenoxide [O-2,6-Ph2-C6H3]−, have been prepared. A diversity of coordination patterns is observed in the solid state for both homoleptic and heteroleptic complexes, with coordination numbers ranging between 2 and 4. The identity of the bridging ligand in heteroleptic dimers [Ba(μ2-X1)(X2)]2 depends largely on the given pair of ligands X1 and X2. Experimentally, the propensity to fill the bridging position increases according to [OB{CH(SiMe3)2}2)]−<[N(SiMe3)2]−<[OSi(SiMe3)3]−<[O(2,6-Ph2-C6H3)]−<[OB(2,4,6-iPr3-C6H2)2]−. This trend is the overall expression of 3 properties: steric constraints, electronic density and σ- and π-donating capability of the negatively charged atom, and ability to generate Ba ⋅ ⋅ ⋅ F, Ba ⋅ ⋅ ⋅ C(π) or Ba ⋅ ⋅ ⋅ H−C secondary interactions. The comparison of the structural motifs in the complexes [Ae{μ2-N(SiMe3)2}(OB{CH(SiMe3)2}2)]2 (Ae = Mg, Ca, Sr and Ba) suggest that these observations may be extended to all alkaline earths. DFT calculations highlight the largely prevailing ionic character of ligand-Ae bonding in all compounds. The ionic character of the Ae-ligand bond encourages bridging coordination, whereas the number of bridging ligands is controlled by steric factors. DFT computations also indicate that in [Ba(μ2-X1)(X2)]2 heteroleptic dimers, ligand predilection for bridging vs. terminal positions is dictated by the ability to establish secondary interactions between the metals and the ligands. 相似文献
17.
Dr. Antoine Demont Dr. Carmelo Prestipino Dr. Olivier Hernandez Dr. Erik Elkaïm Serge Paofai Prof. Nikolaï Naumov Dr. Bruno Fontaine Prof. Régis Gautier Dr. Stéphane Cordier 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(38):12711-12719
The crystal structure of Cs2BaTa6Br15O3 has been elucidated by using synchrotron X‐ray powder diffraction and absorption experiments. It is built from edge‐bridged octahedral [(Ta6${{\rm Br}{{{\rm i}\hfill \atop 9\hfill}}}$ ${{\rm O}{{{\rm i}\hfill \atop 3\hfill}}}$ )${{\rm Br}{{{\rm a}\hfill \atop 6\hfill}}}$ ]4? cluster units with a singular poor metallic electron (ME) count equal to thirteen. This leads to a paramagnetic behaviour related to one unpaired electron. The arrangement of the Ta6 clusters is similar to that of Cs2LaTa6Br15O3 exhibiting 14‐MEs per [(Ta6${{\rm Br}{{{\rm i}\hfill \atop 9\hfill}}}$ ${{\rm O}{{{\rm i}\hfill \atop 3\hfill}}}$ )${{\rm Br}{{{\rm a}\hfill \atop 6\hfill}}}$ ]5? motif. The poorer electron‐count cluster presents longer metal–metal distances as foreseen according to the electronic structure of edge‐bridged hexanuclear cluster. Density functional theory (DFT) calculations on molecular models were used to rationalise the structural properties of 13‐ and 14‐ME clusters. Periodic DFT calculations demonstrate that the electronic structure of these solid‐state compounds is related to those of the discrete octahedral units. Oxygen–barium interactions seem to prevent the geometry of the octahedral cluster to strongly distort, allowing stabilisation of this unprecedented electron‐poor Ta6 cluster in the solid state. 相似文献
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Damien Montarnal Philippe Cordier Corinne Soulié‐Ziakovic François Tournilhac Ludwik Leibler 《Journal of polymer science. Part A, Polymer chemistry》2008,46(24):7925-7936
We describe the synthesis of supramolecular self‐healing elastomers from vegetable oil fatty acid derivatives, diethylene triamine, and urea. Our strategy to obtain materials that are self‐healing but do not flow relies on the use of a wide molecular distribution of randomly branched oligomers equipped with self‐complementary and complementary hydrogen bonding groups. We prepared such oligomers with a two steps procedure. In the first step, diethylene triamine was condensed with dimer acids. In the second step, the oligomers obtained were allowed to react with urea. The molecules were characterized by NMR and IR spectroscopies and Monte‐Carlo simulations were used to analyze the molecular size distribution. The sensitivity to small variations of the experimental conditions has been examined and the robustness of the synthetic procedure optimized. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7925–7936, 2008 相似文献