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51.
Denis A. Svechkarev Ilya V. Bukatich Andrey O. Doroshenko 《Journal of photochemistry and photobiology. A, Chemistry》2008,200(2-3):426-431
Two novel 1,3,5-triphenyl-2-pyrazoline moiety containing derivatives of 3-hydroxychromone were synthesized and studied by 1H NMR, absorption and fluorescence spectroscopy. The prospects of practical application of these compounds exhibiting high solvatofluorochromism into analytical chemistry and biophysics as effective ratiometric polarity probes were discussed proceeding from the data on their fluorescent properties. 相似文献
52.
Bis-paddlewheel heterobimetallic complexes in which palladium(II) is connected to the rare-earth metals(III) [Pd(μ-OOCMe)4Ln(OH2)(μ,η2-OOCMe)]2 × 2HOOCMe (Ln = Nd, Sm, Eu, Yb and Tm) by four acetate bridges were synthesised by the reaction of Pd3(μ-OOCMe)6 with the LnIII acetates. The tetraacetate-bridged complexes were unexpectedly found to be readily transformed by the stoichiometric amount of pivalic acid into the mono-paddlewheel tetrapivalate-bridged analogues in which the paddlewheel structure [Pd(μ-OOCR)4Ln] maintains as established by X-ray crystallography. The role of the intra- and intermolecular H-bonding in these complexes is discussed. 相似文献
53.
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55.
Background
Triptolide is a diterpene triepoxide from the Chinese medicinal plant Tripterygium wilfordii Hook F., with known anti-inflammatory, immunosuppressive and anti-cancer properties. 相似文献56.
Irena Pankratov Sara Elhanany Sharona Henig Shunit Zaritsky Ivan Ostapenko Ilya Kuselman 《Accreditation and quality assurance》2010,15(8):459-466
A proficiency testing (PT) scheme was developed for a limited number of analytical laboratories participating in the analysis
of natural water in Israel. Three fit-for-intended-use reference materials (RMs) were prepared for a pilot PT from natural
water: RM-blank and two in-house reference materials (IHRMs) with seven analytes fortified to achieve different levels of
analyte concentrations. The measurands for the PT participants were the traceable spike values certified in the IHRMs, i.e.,
added mass concentrations of the analytes. The RM-blank and IHRMs were found to be homogeneous and stable over 11 days, the
time necessary for the experimental part of the PT. The RMs were distributed to the PT participants as unknown test items
similar to routine samples. The test results were evaluated using their deviations from the IHRM-certified values. Eight Israeli
laboratories took part in the interlaboratory comparison. Individual laboratory performance and metrological compatibility
of the PT results of the participants, as a local group of laboratories, were evaluated for every analyte. 相似文献
57.
Ilya N. Egorov Vladimir L. Rusinov Pavel A. Slepukhin Oleg N. Chupakhin 《Journal of chemical crystallography》2010,40(4):387-390
Abstract
The diastereoselective synthesis, NMR and X-ray structure of (S)-2-((S)-2-(N-Ts-amino)-3-methylbutanoyl)-3-(1H-indol-3-yl)-6-phenyl-3,4-dihydro-1,2,4-triazin-5(2H)-one—a potential antivirus agent are reported. The compound crystallizes in the triclinic space group P1 with unit cell parameters: a = 5.9259(6) ?, b = 9.6370(12) ?, c = 12.9541(9) ?, α = 109.210(9)°, β = 90.804(7)°, γ = 105.074(10)° and Z = 1. 相似文献58.
Hogben HJ Krzystyniak M Charnock GT Hore PJ Kuprov I 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2011,208(2):179-194
We introduce a software library incorporating our recent research into efficient simulation algorithms for large spin systems. Liouville space simulations (including symmetry, relaxation and chemical kinetics) of most liquid-state NMR experiments on 40+ spin systems can now be performed without effort on a desktop workstation. Much progress has also been made with improving the efficiency of ESR, solid state NMR and Spin Chemistry simulations. Spinach is available for download at http://spindynamics.org. 相似文献
59.
de Fouquieres P Schirmer SG Glaser SJ Kuprov I 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2011,212(2):412-417
We report some improvements to the gradient ascent pulse engineering (GRAPE) algorithm for optimal control of spin ensembles and other quantum systems. These include more accurate gradients, convergence acceleration using the Broyden–Fletcher–Goldfarb–Shanno (BFGS) quasi-Newton algorithm as well as faster control derivative calculation algorithms. In all test systems, the wall clock time and the convergence rates show a considerable improvement over the approximate gradient ascent. 相似文献
60.
Kummerlöwe G Grage SL Thiele CM Kuprov I Ulrich AS Luy B 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2011,209(1):19-30
The successful measurement of anisotropic NMR parameters like residual dipolar couplings (RDCs), residual quadrupolar couplings (RQCs), or residual chemical shift anisotropy (RCSA) involves the partial alignment of solute molecules in an alignment medium. To avoid any influence of the change of environment from the isotropic to the anisotropic sample, the measurement of both datasets with a single sample is highly desirable. Here, we introduce the scaling of alignment for mechanically stretched polymer gels by varying the angle of the director of alignment relative to the static magnetic field, which we call variable angle NMR spectroscopy (VA-NMR). The technique is closely related to variable angle sample spinning NMR spectroscopy (VASS-NMR) of liquid crystalline samples, but due to the mechanical fixation of the director of alignment no sample spinning is necessary. Also, in contrast to VASS-NMR, VA-NMR works for the full range of sample inclinations between 0° and 90°. Isotropic spectra are obtained at the magic angle. As a demonstration of the approach we measure 13C-RCSA values for strychnine in a stretched PDMS/CDCl? gel and show their usefulness for assignment purposes. In this context special care has been taken with respect to the exact calibration of chemical shift data, for which three approaches have been derived and tested. 相似文献