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81.
Beşli S Coles SJ Davies DB Kılıç A Shaw RA 《Dalton transactions (Cambridge, England : 2003)》2011,40(19):5307-5315
Cyclotriphosphazene derivatives containing a P-NHR group in the side-chain react in the presence of a strong base to form stable intermolecular bridged products. Reaction of sodium hydride with mono-spiro cyclophosphazene derivatives having a P-NH group, N(3)P(3)Cl(4)[O(CH(2))(3)NH], (1a) or N(3)P(3)Cl(4)[CH(3)N(CH(2))(3)NH], (1b) leads to formation of bis-cyclophosphazenes bridged with an eight-membered cyclophosphazene ring in an ansa arrangement (2a, 2b) whereas reaction of sodium hydride with mono-amino cyclophosphazene derivatives [N(3)P(3)Cl(5)(NHR), R = n-hexyl, 3a; i-Pr, 3b; Ph, 3c] give bis-cyclophosphazenes bridged with a four-membered cyclophosphazane ring in a spiro arrangement (4a-c). In the latter reaction P-O-P bridged compounds (5a-c) were also obtained as a result of hydrolysis reactions associated with the amount of moisture in the solvent tetrahydrofuran. In addition, it was found that reaction of a mixture of cyclotriphosphazene with either mono spiro compound, (1a) or (1b), in the presence of sodium hydride lead to formation of the first examples of asymmetrically-bridged cyclophosphazenes (6a-b). 相似文献
82.
K.B. Be? A.S. MuszyńskiN. Michniewicz W. WrzeszczA. Kotynia J.P. Hawranek 《Vibrational Spectroscopy》2011,55(1):44-48
The spectrum of the complex refractive index in the 15,000-100 cm−1 region was determined for liquid di-iso-propylether from transmission studies. In the MIR region very thin layers with thicknesses of a few micrometers had to be used to obtain reliable data. FT-Raman spectra of the liquid are also reported. Identifications for numerous bands observed in the liquid phase were proposed based on results of a conformational analysis and modeling of vibrational spectra using DFT calculations. 相似文献
83.
V.?Yu.?Tarenkov A.?I.?D’yachenko S.?L.?Sidorov V.?A.?Bo?chenko D.?I.?Bo?chenko ?.?Chromik V.??trbík ?.?Ga?i M.??panková ?.?Beňa?ka 《Physics of the Solid State》2009,51(9):1778-1784
The specific features of the phonon spectrum of the MgB2 compound (T
c
= 38 K) are investigated by tunneling spectroscopy. It is demonstrated that both the position and the energy width of the
fundamental optical mode E
2g
in the phonon spectrum are in good agreement with inelastic X-ray spectroscopy data but differ substantially from Raman spectroscopy
results. Among possible factors responsible for this discrepancy, the anharmonic and nonadiabatic effects that are characteristic
of the MgB2 system are discussed. 相似文献
84.
Mária Szaszkó István Hajdú Beáta Flachner Krisztina Dobi Csaba Magyar István Simon Zsolt Lőrincz Zoltán Kapui Tamás Pázmány Sándor Cseh György Dormán 《Molecular diversity》2017,21(1):175-186
A glutaminyl cyclase (QC) fragment library was in silico selected by disconnection of the structure of known QC inhibitors and by lead-like 2D virtual screening of the same set. The resulting fragment library (204 compounds) was acquired from commercial suppliers and pre-screened by differential scanning fluorimetry followed by functional in vitro assays. In this way, 10 fragment hits were identified (\(\sim \)5 % hit rate, best inhibitory activity: 16 \(\upmu \hbox {M}\)). The in vitro hits were then docked to the active site of QC, and the best scoring compounds were analyzed for binding interactions. Two fragments bound to different regions in a complementary manner, and thus, linking those fragments offered a rational strategy to generate novel QC inhibitors. Based on the structure of the virtual linked fragment, a 77-membered QC target focused library was selected from vendor databases and docked to the active site of QC. A PubChem search confirmed that the best scoring analogues are novel, potential QC inhibitors. 相似文献
85.
L. Aldea F. Bečvář J. Honzátko S. Pospíšil S. A. Telezhnikov 《Czechoslovak Journal of Physics》1977,27(9):1002-1008
The173Yb(n, γ)174Yb reaction was measured at the Pulsed Fast Reactor. Intensities of 9 primary transitions toJ π =1+, 2 or 3+ levels below 1960 keV for 9 resonances withJ π =2? were examined. Statistically significant correlation between reduced neutron widths and partial radiation widths has been observed. 相似文献
86.
87.
88.
De Wasch K Be Brabander HF Impens S Vandewiele M Courtheyn D 《Journal of chromatography. A》2001,912(2):311-317
This paper describes a method for extraction of tapazol, thiouracil, methylthiouracil, propylthiouracil and mercaptobenzimidazol (MBI) from thyroid tissue. The solid-phase extraction procedure is optimized to obtain the maximum results for the main thyreostats including MBI. Different combinations of sample application, column conditioning and wash steps were tested. The analytes were extracted from the matrix with methanol. After solid-phase extraction they were derivatised with 7-chloro-4-nitrobenzo-2-furazan. Determination is carried out using liquid chromatography-electrospray mass spectrometry. The identification of the analytes was performed according to the final revision of the EU criteria (93/256/EC decision). The detection capability was 20 microg kg(-1) for all mentioned thyreostats. 相似文献
89.
Jaka Horvat Marija Bešter-Rogač Cveto Klofutar Darja Rudan-Tasic 《Journal of solution chemistry》2008,37(9):1329-1342
The viscosities of aqueous solutions of lithium, sodium, potassium, rubidium and caesium cyclohexylsulfamates were measured
at 293.15, 298.15, 303.15, 313.15 and 323.15 K. The relative viscosity data were analyzed and interpreted in terms of the
Kaminsky equation, η
r=1+Ac
1/2+Bc+Dc
2. The viscosity A-coefficient was calculated from the Falkenhagen-Dole theory. The viscosity B-coefficients are positive and relatively large. Their temperature coefficient ∂
B/∂
T is negative or near zero for lithium and sodium salts whereas for potassium, rubidium and caesium salts it is positive. The
viscosity D-coefficient is positive. This was explained by the size of the ions, structural solute–solute interactions, hydrodynamic
effect, and by higher terms of the long-range Debye-Hückel type of forces. From the viscosity B-coefficients the thermodynamic functions of activation of viscous flow were calculated. The limiting partial molar Gibbs
energy of activation of viscous flow of the solute was divided into contributions due to solvent molecules and the solute
in the transition state. The activation energy of the solvent molecules was calculated using the limiting Gibbs energy of
activation for the conductance of the solute ions. The activation energy of the solvent molecules was then discussed in terms
of the nature of the alkali-metal ions and their influence on the structure of water. The limiting activation entropy and
enthalpy of the solute for activation of viscous flow were interpreted by ion-solvent bond formation or breaking in the transition
state of the solvent. The hydration numbers of the investigated electrolytes were calculated from the specific viscosity of
the solutions. 相似文献
90.
J. Honzátko K. Konečn'y F. Bečvář E. A. Eissa M. Králík 《Zeitschrift für Physik A Hadrons and Nuclei》1981,302(2):183-184
The importance of surface effects on nuclear level densities is stressed and numerically estimated within the framework of the Thomas-Fermi model. 相似文献