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261.
262.
Félicité Misago Jacques Walrand Ghislain Blanquet 《Journal of Molecular Spectroscopy》2006,237(1):46-52
Using a tunable diode-laser spectrometer, N2-broadening coefficients have been measured for 15 lines in the ν3 band of C32S2 at room and low temperatures (298, 273.2, 248.2, 223.2, and 198.2 K). These lines with J values ranging from 2 to 62 are located in the spectral range 1519-1545 cm−1. The collisional widths are obtained by fitting each measured spectral line with a Voigt and a Rautian lineshape model and for a few lines we also used a Galatry model. From these results, we have determined the n parameter of the temperature dependence of each broadening coefficient. A semiclassical calculation of these broadenings has been performed by considering in addition to the main electrostatic quadrupole-quadrupole interaction an anisotropic dispersion contribution leading to satisfactory results at all temperatures and providing the n temperature dependence parameter in good agreement with the experimental determination. 相似文献
263.
YouMingWANG YuXinLI SuHuaWANG ZhengMingLI 《中国化学快报》2004,15(10):1135-1136
β-Keto-δ-valerolactones, which were obtained by reaction of acetoacetate with aldehydes or ketones, reacted with carbon disulfide, alkyl halides and a new condensation reaction was developed. The structures of the products 3 were confirmed by ^1HNMR spectra and elemental analysis. 相似文献
264.
In the presence of Et4NCl?H2O,reaction of AgCl with TabHPF6 in MeCN afforded the title complex {(Tab-Tab)[Ag2(μ-Cl)4]·2MeCN}n 1.1 crystallizes in the orthorhombic space group Pbcn with a=16.782(3),b=6.8358(14),c=26.194(5) ,V=3004.9(10) 3,Z=8,μ= 1.817 mm-1,Dc=1.711 g/cm3,T=223 K,C11H16AgCl2N2S,Mr=387.10,F(000)=1544,S=1.160,R=0.0528 and wR=0.0896 for 2732 observed reflections with I > 2σ(I).1 contains a 1D linear [Ag2Cl4]n2n-chain coupled with the [Tab-Tab]2+ dications.Intermolecular hydrogen bonding interac-tions between the protons of methyl groups from the Tab-Tab dications and the chlorides result in the formation of a 2D hydrogen-bonded network. 相似文献
265.
266.
The living radical polymerization of styrene in bulk was successfully performed with a tetraethylthiuram disulfide/copper bromide/2,2′‐bipyridine (bpy) initiating system. The initiator Et2NCS2Br and the catalyst cuprous bromide (CuBr) were produced from the reactants in the system through in situ atom transfer radical polymerization (ATRP). A plot of natural logarithm of the ratio of original monomer concentration to monomer concentration at present, ln([M]0/[M]) versus time gave a straight line, indicating that the kinetics was first‐order. The number‐average molecular weight from gel permeation chromatography (GPC) of obtained polystyrenes did not agree well with the calculated number‐average molecular weight but did correspond to a 0.5 initiator efficiency. The polydispersity index (i.e., the weight‐average molecular weight divided by the number‐average molecular weight) of obtained polymers was as low as 1.30. The resulting polystyrene with α‐diethyldithiocarbamate and ω‐Br end groups could initiate methyl methacrylate polymerization in the presence of CuBr/bpy or cuprous chloride/bpy complex catalyst through a conventional ATRP process. The block polymer was characterized with GPC, 1H NMR, and differential scanning calorimetry. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 4001–4008, 2001 相似文献
267.
《Journal of polymer science. Part A, Polymer chemistry》2018,56(13):1358-1365
A multiblock copolymer consisting of hard (poly(arylene ether sulfone)) and soft (poly(alkyl disulfide)) segments was successfully synthesized by oxidative coupling of the corresponding thiol‐terminated oligomers. Its structure was confirmed by 1H and 13C NMR spectroscopy. The GPC data (Mw = 82,000, Mw/Mn = 2.7) and inherent viscosity (0.67 dL g−1) indicated the formation of a high‐molecular‐weight multiblock copolymer, while AFM and DSC indicated a microphase‐separated morphology. Tensile testing of the multiblock copolymer films showed a large elongation at break, which is characteristic of microphase‐separated hard/soft multiblock copolymers. Over 90% of the elongation at break of damaged samples (notched or cut) was recovered by UV irradiation. The elongation recovery was proportional to the UV irradiation energy, and the high recovery was achieved by relatively weak irradiation (<170 J cm−2). The high content of disulfide bonds in the multiblock copolymer resulted in a lower self‐healing energy. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 1358–1365 相似文献
268.
Abstract Several beamlines at the European Synchrotron Radiation Facility in Grenoble are being designed with high-pressure experiments in mind. Among the first seven beamlines the Microfocus Beamline, the Materials Science Beamline, the Laue White Beamline and the High Energy Beamline are of particular interest for high-pressure diffraction experiments. These experimental stations are outlined and their characteristics are compared. Presented at the IUCr Workshop on ‘Synchrotron Radiation Instrumentation for High Pressure Crystallography’, Daresbury Laboratory 20-21 July 1991 相似文献
269.
Hee Joon LeeKyungho Park Goun BaeJaehoon Choe Kwang Ho Song Sunwoo Lee 《Tetrahedron letters》2011,52(39):5064-5067
Unsymmetric diaryl alkynes were synthesized from the palladium-catalyzed decarboxylative coupling of aryl halides and propiolic acid using a continuous flow reaction system. This flow chemistry system continuously gave the desired products in moderate to good yields, and produced less byproduct than was formed in the batch reaction. 相似文献
270.