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41.
A complete assignment of the 1H, 13C and 19F NMR spectra of 1,1,4,4-tetrafluoro-2-propylidene-3-methyl-6-tert-butyl-1,4-disila-5-cyclohexene 3, the product of the cycloaddition reaction between tetrafluorodisilacyclobutene 1 and cis, trans-2,4-hexadiene mediated by (n5-C5H5)Mn(CO)3, has been made by means of various 2D NMR chemical shift correlation methods and selective heteronuclear decoupling techniques. An analysis of the three bond 13C-1H coupling constants and two bond 13C-19F coupling constants and the molecular modeling results enabled the determination of the conformation and configuration of compound 3. The conformation of 3 provides insight into mechanistic details of the Mn-mediated cycloaddition. 相似文献
42.
S. N. Dmitrieva N. I. Sidorenko A. I. Vedernikov L. G. Kuz’mina J. A. K. Howard T. M. Buslaeva S. P. Gromov 《Russian Chemical Bulletin》2007,56(5):993-1002
The condensation reaction of 1,2-bis(2-haloethoxy)-4-nitrobenzenes with acyclic α,ω-(oxa)alkanedithiols in the presence of
alkali metal carbonates produced a series of nitrobenzodithiacrown ethers with macrocycles of different size. The structures
of three ethers were established by X-ray diffraction. A new method was developed for the synthesis of nitrobenzomonothia-15-crown-5
ether. Nitro derivatives of benzodithiacrown ethers were tested as reagents for extraction of palladium(II), platinum(IV), and rhodium(III) from hydrochloric acid solutions. Extraction of PdII salts was found to be highly selective compared to that of PtIV and RhIII salts. Benzodithia-15-crown-5 ether is the most efficient extractant for palladium(II). Reduction of nitrobenzothiacrown ethers with hydrazine hydrate in the presence of a platinum catalyst afforded their amino
derivatives.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 958–966, May, 2007. 相似文献
43.
Z. A. Starikova A. I. Yanovsky Yu. T. Struchkov S. V. Zubkov I. I. Seifullina 《Russian Chemical Bulletin》1996,45(9):2157-2162
The crystal structure of the product of the condensation of (salicylideneamino)nitroguanidine with salicylaldehyde on a Ni2+ ion template, K[Ni(C15H10N5O4)] · DMF, has been studied. It was established that a planar Ni complex, consisting of isolated [NiL]– anions and solvated [K+ · DMF] cations, is formed. The negative charge of the anion is localized mainly on the O atoms of the nitro group. The nitroguanidine fragment of the ligand occurs in the tautomeric form, which was not reported previously.Deceased in 1995Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 2273–2277, September, 1996. 相似文献
44.
Improved separations of the isomers of olefinic aliphatic insect pheromones were obtained on cholesteryl cinnamate glass capillary columns by operating in the supercooled temperature range of the liquid crystal. Capillary columns were prepared with varying film thickness of the stationary phase; choice of the correct film thickness ensured optimum retention for a wide range of compounds within the most effective temperature range of the liquid crystal. The deactivation procedures described made the liquid crystal columns suitable for separation of the geometric isomers of polar and nonpolar compounds. 相似文献
45.
A novel series of the formula NdSrNi1−xCuxO4−δ were synthesized for various values of x ranging from 0 to 1 in 1 atm of O2 gas flow using conventional solid-state methods and were characterized by powder X-ray diffraction and electrical resistivity measurements. The compounds have been shown to adopt the K2NiF4-type structure. The oxygen stoichiometry of the compounds was determined from thermo-gravimetric analysis (TGA). An analysis of the micro-structure of the neodymium strontium nickel copper oxide is described. All the samples were semi-conducting from room temperature down to 77 K. The effect of Cu2+ incorporation on the structural and electrical properties of NdSrNi1−xCuxO4−δ, 0?x?1, are discussed in terms of Jahn-Teller distortion of the (Ni/Cu)O6 octahedra and mixed valence character of copper. 相似文献
46.
Picquart M. López T. Gómez R. Torres E. Moreno A. Garcia J. 《Journal of Thermal Analysis and Calorimetry》2004,76(3):755-761
Sol-gel zirconia was characterized using high-resolution thermogravimetry (Hi-Res TG) and differential scanning calorimetry
(DSC) and compared with X-ray diffraction, Raman scattering, and UV-Vis spectroscopy. ZrO2-x(OH)2x·yH2O annealed below 400°C show typical behavior of amorphous material. As the annealing temperature is increased, the tetragonal
and monoclinic phases crystallize. Typical Hi-Res TG curve shows that the samples are continuously dehydrated in a long temperature
range, between room temperature and 600°C. The total mass loss relative to the initial mass is of about 29%. The DSC analysis
coupled with TG and structural information, indicate that the exothermic processes about 355 and 447°C can be related to the
nucleation process of the formation of tetragonal zirconia, with bulk crystallization at 447°C.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
47.
V. V. Sharutin O. K. Sharutina L. G. Mel'nikova G. K. Fukin L. N. Zakharov A. I. Yanovsky Yu. T. Struchkovdt 《Russian Chemical Bulletin》1996,45(8):1977-1980
Tetraphenylantimony hydrogen phthalate, Ph4SbOC(O)C6H4000H-o, was prepared by the reaction of pentaphenylantimony with phthalic acid. According to the data of X-ray structural analysis, the resulting compound is a trigonal-bipyramidal complex of antimony with three phenyl groups in equatorial positions; the fourth phenyl group and the carboxyl fragment are in axial positions. The CSbO angle is 177.5(1)° the Sb-C(Ph)eq and Sb-C(Ph)ax distances are 2.099(4)-2.177(4) A and 2.129(4) A, respectively. The H atom of the free carboxyl group and the carbonyl O atom of another carboxylate group form an intramolecular hydrogen bond.DeceasedTranslated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 2082–2085, August, 1996. 相似文献
48.
E. V. Tretyakov A. S. Bogomyakov E. Yu. Fursova G. V. Romanenko V. N. Ikorskii V. I. Ovcharenkoa 《Russian Chemical Bulletin》2006,55(3):457-463
The molecular and crystal structures of porphyrexides, viz., 4-amino-2-imino-(1) and (Z)-2-amino-4-bromoimino-5,5-dimethyl-4,5-dihydro-1H-imidazole 1-oxyls (7), and their diamagnetic precursors were determined. Compound 1 is kinetically unstable because it is oxidized with atmospheric oxygen to form (E)-1,2-bis[1-amino-1-(cyanoimino)-2-methyl-propan-2-yl]diazene 1,2-dioxide.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 441–447, March, 2006. 相似文献
49.
Piotr Kowalski Marcin Marszałł Ilona Olędzka Wojciech Czarnowski 《Chromatographia》2007,66(5-6):357-361
Two rapid and popular methods—capillary electrophoresis (CE) and high-performance liquid chromatography (HPLC) have been compared
for analysis of cotinine in human urine. Cotinine was analyzed in less than 7 min, with detection limits of 5 and 3.2 ng mL−1 for CE and HPLC, respectively. The performance of the methods was evaluated in terms of sensitivity, specificity, precision,
accuracy, and limits of detection and quantification. Calibration plots were linear in the range 50–4,000 ng mL−1, at least, and mean recoveries were satisfactory for both techniques. The methods were successfully used for quantification
of cotinine in urine. 相似文献
50.
N.V. Loginova T.V. Kovalchuk R.A. Zheldakova A.A. Chernyavskaya N.P. Osipovich G.K. Glushonok G.I. Polozov V.N. Povalishev V.L. Sorokin O.I. Shadyro 《Polyhedron》2006,25(18):3603-3610
Cu (II) complexes with 3,5-di(tert-butyl)-1,2-benzenediol (I), 4,6-di(tert-butyl)-1,2,3-benzentriol (II) and sulfur-containing sterically hindered o-diphenol derivatives such as 4,6-di(tert-butyl)-3-(2-hydroxyethylsulfanyl)-1,2-benzenediol (III) and 2-[4,6-di(tert-butyl)-2,3-dihydroxyphenylsulfanyl]acetic acid (IV) have been synthesized and characterized by means of elemental analysis, TG/DTA, FT-IR, ESR, XPS, XPD and conductivity measurements. Antifungal activities of these ligands and their respective Cu (II) complexes have been determined against Aspergillus niger, Fusarium sp., Penicillium lividum, Mucor sp. and Botrytis cinerea. Most of the compounds (both the free ligands and the complexes) exert pronounced antifungal activities (RI 70%), and virtually all of them (apart from the Cu(LII)2 complex) have the highest inhibitory properties (RI = 100%) against B. cinerea. 相似文献