排序方式: 共有21条查询结果,搜索用时 15 毫秒
1.
Saad Sene Marc Reinholdt Dr. Guillaume Renaudin Dr. Dorothée Berthomieu Prof. Claudio M. Zicovich‐Wilson Prof. Christel Gervais Dr. Philippe Gaveau Prof. Christian Bonhomme Dr. Yaroslav Filinchuk Prof. Mark E. Smith Prof. Jean‐Marie Nedelec Dr. Sylvie Bégu Dr. P. Hubert Mutin Dr. Danielle Laurencin 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(3):880-891
Boronic acids (R‐B(OH)2) are a family of molecules that have found a large number of applications in materials science. In contrast, boronate anions (R‐B(OH)3?) have hardly been used so far for the preparation of novel materials. Here, a new crystalline phase involving a boronate ligand is described, Ca[C4H9‐B(OH)3]2, which is then used as a basis for the establishment of the spectroscopic signatures of boronates in the solid state. The phase was characterized by IR and multinuclear solid‐state NMR spectroscopy (1H, 13C, 11B and 43Ca), and then modeled by periodic DFT calculations. Anharmonic OH vibration frequencies were calculated as well as NMR parameters (by using the Gauge Including Projector Augmented Wave—GIPAW—method). These data allow relationships between the geometry around the OH groups in boronates and the IR and 1H NMR spectroscopic data to be established, which will be key to the future interpretation of the spectra of more complex organic–inorganic materials containing boronate building blocks. 相似文献
2.
Dr. Mégane Muschi Anusha Lalitha Dr. Saad Sene Dr. Damien Aureau Dr. Mathieu Fregnaux Dr. Imène Esteve Dr. Lucie Rivier Dr. Naseem Ramsahye Dr. Sabine Devautour-Vinot Dr. Clémence Sicard Prof. Nicolas Menguy Dr. Christian Serre Prof. Guillaume Maurin Prof. Nathalie Steunou 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(26):10439-10444
An innovative strategy is proposed to synthesize single-crystal nanowires (NWs) of the Al3+ dicarboxylate MIL-69(Al) MOF by using graphene oxide nanoscrolls as structure-directing agents. MIL-69(Al) NWs with an average diameter of 70±20 nm and lengths up to 2 μm were found to preferentially grow along the [001] crystallographic direction. Advanced characterization methods (electron diffraction, TEM, STEM-HAADF, SEM, XPS) and molecular modeling revealed the mechanism of formation of MIL-69(Al) NWs involving size-confinement and templating effects. The formation of MIL-69(Al) seeds and the self-scroll of GO sheets followed by the anisotropic growth of MIL-69(Al) crystals are mediated by specific GO sheets/MOF interactions. This study delivers an unprecedented approach to control the design of 1D MOF nanostructures and superstructures. 相似文献
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4.
“In-situ” monitoring activation and reaction on very absorbing catalytic solid by DRIFT spectrometer
Christophe Depecker Pierre Legrand Abdoulaye Sene Geneviève Wrobel 《Mikrochimica acta》1988,95(1-6):119-122
The FTIR's well-known advantages are strongly shown by the use of new infrared techniques. Both advantages of FTIR and diffuse reflectance make this coupling particularly important in the development of infrared studies.Sensitivity and rapidity of the FTIR spectrometer, added to the extremely simple preparation of the sample, allowed by diffuse reflectance attachment, give a high performing tool particularly in catalysis in the view of understanding the catalytic reactions mechanisms. We have chosen thein-situ study of two catalytic systems active in selective hydrogénation of dienes: a copper-chromium oxide and Cu/Al2O3
. 相似文献
5.
Electroactive nickel(II) hexacyanoferrate (NiHCF) thin film modified electrodes are effective potentiometric sensors for the determination of potassium ions. The NiHCF films are deposited onto glassy carbon electrodes by repetitive potential cycling in K(3)Fe(CN)(6)/NaNO(3)/Ni(NO(3))(2) solution. The modified electrodes exhibit a linear response to potassium ions in the concentration range 1x10(-3) to 2.0 mol dm(-3), with a near-Nernstian slope (45-49 mV per decade) at 25 degrees C. In the determination of potassium ion in syrups used for treatment of potassium deficiency, the NiHCF-modified electrode gave comparable results to those obtained using flame emission spectrophotometry. 相似文献
6.
P.V. Chliapnikov L.N. Gerdyukov N.G. Minaev A.P. Vorobjev W. Dunwoodie Y. Goldschmidt-Clermont A. Grant Z. Sekera A. Stergiou J. Tuominiemi J.N. Carney D.C. Colley M. James G.T. Jones D. Sherratt F. Grard P. Herquet V. Henri M. Sene 《Physics letters. [Part B]》1974,52(3):375-380
The average charged particle multiplicity, 〈nch(MX2)〉, in the reaction K+p→KoX++ is studied as a function of the mass squared, MX2, of the recoil system X and also as a function of the Ko transverse momentum, pT, at incident momenta of 5.0, 8.2 and 16.0 GeV/c. The complete data samples yield distributions which are not independent of c.m. energy squared, s, They exhibit a linear dependence on log (MX2X/Mo2)[Mo2=1 GeV2] with a change in slope occurring for MX2≈s/2, and do not agree with the corresponding distributions of 〈nch〉 as a function of s for K+ p inelastic scattering. Sub-samples of the data for which Ko production via beam fragmentation, central production and target fragmentation are expected to be the dominant mechanisms show that, within error, the distribution of 〈nch(MX2)〉 versus MX2 is independent of incident momentum for each sub-sample separately. In particular in the beam fragmentation region the 〈nch(MX2)〉 versus MX2 distribution agrees rather well with that of 〈nch〉 versus s for inelastic K+p interactions. The latter result agrees with recent results on the reactions pp → pX and π?p → pX in the NAL energy range. Evidence is presented for the presence of different production mechanisms in these separate regions. 相似文献
7.
Sene Luciane Felipe Maria G. A. Silva Silvio S. Vitolo Michele 《Applied biochemistry and biotechnology》2001,91(1-9):671-680
Candida guilliermondii FTI 20037 was cultured in sugarcane bagasse hydrolysate supplemented with 2.0 g/L of (NH4)2SO4, 0.1 g/L of CaCl2·2H2O, and 20.0 g/L of rice bran at 35°C; pH 4.0; agitation of 300 rpm; and aeration of 0.4, 0.6, or 0.8 vvm. The high xylitol
production (20.0 g/L) and xylose reductase (XR) activity (658.8 U/mg of protein) occurred at an aeration of 0.4 vvm. Under
this condition, the xylitol dehydrogenase (XD) activity was low. The apparent K
M for XR and XD against substrates and cofactors were as follows: for XR, 6.4×10−2
M (xylose) and 9.5×10−3 mM (NADPH); for XD, 1.6×10−1
M (xylitol) and 9.9×10−2 mM (NAD+). Because XR requires about 10-fold less xylose and cofactor than XD for the condition in which the reaction rate is
half of the V
max, some interference on the overall xylitol production by the yeast could be expected. 相似文献
8.
Partial cross sections are presented for the various topologies in 13.1 GeV/c pp interactions. The transverse and c.m. longitudinal momenta distributions for nucleons and pions are given. The variation of〈pT〉 and are presented as a function of the multiplicity The best fit of the pT and distributions is obtained with functions suggested by the thermodyanamical model. The collimation and asymmetry parameters are given. Di-pions and tripions correlations are studied. 相似文献
9.
Ring-opening reactions of functionalized 1,2-cyclic sulfates and oxetanes with the phosphonodifluoromethyl carbanion are reported. This approach allows an easy access to fluorinated beta-hydroxyphosphonates that are building blocks in the synthesis of acyclic nucleosides. Synthesis of precursors of nucleoside phosphorylase inhibitors from these alcohols is described. 相似文献
10.
Glass microspheres containing the radioisotope 32P, a β? particle emitter, and half-life of 14.3 days, can be easily introduced in specific human organs such as liver, pancreas, and uterus to kill cancer cells. In the present work phosphate glass microspheres were produced with different compositions and particle size distribution in the range of 20– 30 μm. Two different thermal processes were used to spherodize glass particles originally with irregular shapes. Samples were characterized by X-rays diffraction to check the amorphous structure, energy dispersive X-rays fluorescence spectroscopy to determine the final glass composition, and Fourier transformed infrared spectroscopy to determine the structural groups in the glass structure. The dissolution rate of glass samples in water was determined at 90 °C, and in simulated body fluid (SBF) at 37 °C. Glasses with dissolution rates close to 10?5 g/(cm2 day) were obtained, which make them suitable for the present application. Scanning electron microscopy was used to evaluate the shape of the microspheres before and after the dissolution tests. The cytotoxicity tests showed that these microspheres can be used for biological applications. 相似文献