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111.
Bachir Bentria Djamal Benbertal Zoulikha Hebboul Muriel Bagieu‐Beucher Alain Mosset 《无机化学与普通化学杂志》2005,631(5):894-901
The investigation of CdCl2‐HIO3 system, in aqueous and HNO3 solutions, revealed that anhydrous cadmium iodate presents a marked polymorphism. No less than four new Cd(IO3)2polymorphs have been isolated and characterized, two of which showing second harmonic generation activity. Single crystals of ε‐Cd(IO3)2 are obtained by slowly evaporating, at 60 °C, a saturated solution of γ‐Cd(IO3)2 in 30 % nitric acid. This compound crystallizes in the orthorhombic space group Pca21 [a = 17.581(2), b = 5.495(2), c = 11.163(2) Å]. The basic structural unit can be described as the connection of two cadmium polyhedrons with a short metal – metal distance of 3.88Å. These units are further linked through two other iodate bridges resulting in layers parallel to the (100) plane. The 3D linkage is ensured by short bonds of the fourth iodate group. 相似文献
112.
Bourgeois ME Wajer FT Roth M Briguet A Décorps M van Ormondt D Segebarth C Graveron-Demilly D 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2003,163(2):277-287
This paper analyzes the effects of intra-scan motion and demonstrates the possibility of correcting them directly in k-space with a new automatic retrospective method. The method is presented for series of 2D acquisitions with Cartesian sampling. Using a reference k-space acquisition (corrected for translations) within the series, intra-scan motion parameters are accurately estimated for each trajectory in k-space of each data set in the series resulting in pseudo-random sample positions. The images are reconstructed with a Bayesian estimator that can handle sparse arbitrary sampling in k-space and reduces intra-scan rotation artefacts to the noise level. The method has been assessed by means of a Monte Carlo study on axial brain images for different signal-to-noise ratios. The accuracy of motion estimates is better than 0.1 degrees for rotation, and 0.1 and 0.05 pixel, respectively, for translation along the read and phase directions for signal-to-noise ratios higher than 6 of the signals on each trajectory. An example of reconstruction from experimental data corrupted by head motion is also given. 相似文献
113.
The self-broadening coefficients and the intensities of 29 lines in the nu(1) band of cyanogen chloride ((35)Cl(12)C(14)N) have been measured at high resolution in the range 699-736 cm(-1), using a tunable diode-laser spectrometer. The collisional widths and most of the intensities are obtained by fitting Voigt and Rautian profiles to the measured shapes of the lines. From the analysis of the line intensities we determine the absolute strength as well as the Herman-Wallis factors for the nu(1) band. A semiclassical calculation of the self-broadening coefficients, performed by considering the main electrostatic interactions only, has provided larger results than the experimental data. Copyright 2001 Academic Press. 相似文献
114.
Yoann Marsac Stéphanie Legoupy Muriel Pipelier François Huet 《Tetrahedron letters》2004,45(34):6461-6463
When compounds 3a and 3b were subjected to a Mitsunobu reaction with benzoylthymine, the expected substitution products were formed together with the regioisomers corresponding to benzyloxy group migrations. 相似文献
115.
Leca D Song K Amatore M Fensterbank L Lacôte E Malacria M 《Chemistry (Weinheim an der Bergstrasse, Germany)》2004,10(4):906-916
Reaction of sulfonamides with iodosobenzene leads to phenyliodinanes. A new catalysis reaction of the decomposition of these products in the presence of sulfoxides that allows the smooth synthesis of sulfoximines has been evidenced and studied: copper(II) salts were used to prepare compounds 4 a-j and 5 b, d, f, j, k from the corresponding, easily prepared, sulfoxides. The reactions proceed with retention of configuration at the sulfur center, and copper(II) triflate is the best candidate for the catalyst for the imination. Switching from sulfonamides to sulfinamides in the preparation of the starting iodinanes completely alters the reaction pathway: iodinanes are no longer accessible, and sulfonimidates 7 a-j are obtained instead. This behavior can be rationalized by the increase in pK(a) brought about by the removal of one oxygen atom from the sulfur center. Sulfonimidates are interesting molecules with varied applications. Optimization of their one-pot synthesis has been achieved by carrying out the reaction in acetonitrile. The stereochemical study has shown that the transformation proceeds with global retention of the configuration at the sulfur center, albeit with erosion of the enantiomeric purity. A model accounting for this outcome is proposed. In addition, the presence of oxidized sulfonamide by-products has been explained, and this latter pathway becomes the sole one when alcohol is replaced by water. Good yields of the oxidized products are obtained. 相似文献
116.
Blanzat M Turrin CO Perez E Rico-Lattes I Caminade AM Majoral JP 《Chemical communications (Cambridge, England)》2002,(17):1864-1865
We report the synthesis and the supramolecular auto-assembly of catanionic phosphorus-containing dendrimers mimicking multisite analogs of galactosylceramide. 相似文献
117.
Hui Wang Lorenzo Vendrame Dr. Christophe Fliedel Dr. Si Chen Dr. Florence Gayet Dr. Franck D'Agosto Dr. Muriel Lansalot Dr. Eric Manoury Prof. Rinaldo Poli 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(16):5205-5214
Unimolecular amphiphilic nanoreactors with a poly(4-vinyl-N-methylpyridinium iodide) (P4VPMe+I−) polycationic outer shell and two different architectures (core-cross-linked micelles, CCM, and nanogels, NG), with narrow size distributions around 130–150 nm in diameter, were synthesized by RAFT polymerization from an R0-4VPMe+I−140-b-S50-SC(S)SPr macroRAFT agent by either chain extension with a long (300 monomer units) hydrophobic polystyrene-based block followed by cross-linking with diethylene glycol dimethacrylate (DEGDMA) for the CCM particles, or by simultaneous chain extension and cross-linking for the NG particles. A core-anchored triphenylphosphine (TPP) ligand functionality was introduced by using 4-diphenylphosphinostyrene (DPPS) as a comonomer (5–20 % mol mol−1) in the chain extension (for CCM) or chain extension/cross-linking (for NG) step. The products were directly obtained as stable colloidal dispersions in water (latexes). After loading with [RhCl(COD)]2 to yield [RhCl(COD)(TPP@CCM)] or [RhCl(COD)(TPP@NG)], respectively, the polymers were used as polymeric nanoreactors in Rh-catalyzed aqueous biphasic hydrogenation of the model substrates styrene and 1-octene, either neat (for styrene) or in an organic solvent (toluene or 1-nonanol). All hydrogenations were rapid (TOF up to 300 h−1) at 25 °C and 20 bar of H2 pressure, the biphasic mixture rapidly decanted at the end of the reaction (<2 min), the Rh loss was negligible (<0.1 ppm in the recovered organic phase), and the catalyst phase could be recycled 10 times without significant loss of catalytic activity. 相似文献
118.
Theoretical and experimental characterization of amino‐PEG‐phosphonate‐terminated Polyphosphorhydrazone dendrimers: Influence of size and PEG capping on cytotoxicity profiles
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Aurélien Hameau Séverine Fruchon Christian Bijani Alessandro Barducci Muriel Blanzat Rémy Poupot Giovanni M. Pavan Anne‐Marie Caminade Cédric‐Olivier Turrin 《Journal of polymer science. Part A, Polymer chemistry》2015,53(6):761-774
The synthesis of new series of PPH (poly(phosphorhydrazone)) dendrimers with amino‐PEG phosphonates or the corresponding amino‐PEG phosphonic acids as terminal groups is presented, from generations 1–3. The size of PEG‐terminated dendrimers is experimentally measured by diffusional NMR, and by means of dynamic light scattering. Classical molecular dynamics and well‐tempered metadynamics simulations are used to assess or confirm the formation of aggregates in some cases. The influence of PEG capping on the cytotoxicity profiles of the dendrimers is evaluated on human peripheral blood mononuclear cells by means of LIVE/DEAD assays, and confirms the importance of PEG capping to ensure low cytotoxicity. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 761–774 相似文献
119.
12/14/14‐Helix Formation in 2:1 α/β‐Hybrid Peptides Containing Bicyclo[2.2.2]octane Ring Constraints
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Dr. Baptiste Legrand Dr. Christophe André Laure Moulat Dr. Claude Didierjean Dr. Patrick Hermet Prof. Jean‐Louis Bantignies Prof. Jean Martinez Dr. Muriel Amblard Dr. Monique Calmès 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(34):11986-11990
The highly constrained β‐amino acid ABOC induces different types of helices in β urea and 1:1 α/β amide oligomers. The latter can adopt 11/9‐ and 18/16‐helical folds depending on the chain length in solution. Short peptides alternating proteinogenic α‐amino acids and ABOC in a 2:1 α/β repeat pattern adopted an unprecedented and stable 12/14/14‐helix. The structure was established through extensive NMR, molecular dynamics, and IR studies. While the 1:1 α‐AA/ABOC helices diverged from the canonical α‐helix, the helix formed by the 9‐mer 2:1 α/β‐peptide allowed the projection of the α‐amino acid side chains in a spatial arrangement according to the α‐helix. Such a finding constitutes an important step toward the conception of functional tools that use the ABOC residue as a potent helix inducer for biological applications. 相似文献
120.
Dorian Sonet Mattéo Cayla Dr. Raphaël Méreau Estelle Morvan Aline Lacoudre Dr. Nicolas Vanthuyne Muriel Albalat Dr. Dario M. Bassani Dr. Antoine Scalabre Dr. Emilie Pouget Prof. Dr. Brigitte Bibal 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(72):e202202695
Chiral trifluoromethyl alcohol groups were introduced at the hindered ortho positions of 9,10-diphenylanthracenes to investigate their effects on the physical properties and reactivity towards oxidative dearomatization. In such compact structures, the position in different quadrants and the preferred orientation of the −CH(OH)CF3 groups were determined by the relative and absolute configurations of each stereoisomer, respectively. As a consequence, the stereochemistry governs the organization of the H-bonded molecules in single crystals (homochiral dimers vs ribbon), whereas in chlorinated solvents, they all behave as discrete compounds. Concerning their reactivity, the stereospecific dearomative oxidation of these molecules leads to 9,10-bis-spiro-isobenzofuran-anthracenes, when using organic single-electron transfer oxidants. The chiroptical properties of the alcohols and the corresponding dearomatized products were compared and showed an important modulation of the intensity. 相似文献