共查询到20条相似文献,搜索用时 15 毫秒
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Frank K. Cartledge Joanne M. Wolcott Jacques Dubac Pierre Mazerolles Monique Joly 《Journal of organometallic chemistry》1978,154(2):187-201
Preparations, separations of geometric isomers, and structural assignments based on nmr and on chemical evidence are described for a number of 1-substituted 1,2-dimethylsilacyclopentanes. A number of stereospecific reactions have been observed, and the stereochemistry is in all cases the same as that observed for acyclic silanes. A discussion of the role of ring strain in determining stereochemical outcome and reaction rates is presented. 相似文献
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M.Velazquez Rosenthal T.A. Skotheim A. Melo M.I. Florit M. Salmon 《Journal of Electroanalytical Chemistry》1985,185(2):297-303
Copolymers of pyrrole and N-(p-nitrophenyl)pyrrole have been synthesized electrochemically. Cyclic voltammetric studies show that the electroactivities of both nitrobenzene and polypyrrole are apparent in the copolymer. Growth of poly-N-(p-nitrophenyl)pyrrole films is self-limiting an stops at 200 to 300 nm. Copolymerization allows thick and freestanding films incorporating the nitrophenyl moiety to be grown. 相似文献
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Heat capacities between 160 and 385 K and enthalpies of melting of dl-carvoxime and l-carvoxime were determined by adiabatic calorimetry. The performance of the apparatus was checked on standard n-heptane. The enthalpy of melting values are dl-carvoxime, 22.70 ± 0.06; l-carvoxime, 17.02 ± 0.02; n-heptane, 14.059 ± 0.010 kJ mol−1. 相似文献
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Bogusлaw Misterkiewicz 《Journal of organometallic chemistry》1982,224(1):43-47
An alternative method for the preparation of 1-ferrocenylalkyl alcohols has been developed. This involves condensation of ferrocene with carbonyl compounds in concentrated sulfuric acid and addition of the resulting solutions of 1-ferrocenylalkylium ions into aqueous sodium bicarbonate. The mixtures are then treated with thioglycolic acid and the S-(1-ferrocenylalkyl)thioglycolic acids purified via sodium salts and hydrolysed in the presence of copper powder to give 1-ferrocenylalkyl alcohols in good yields. 相似文献
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H.M. Fahmy B. Nashed F.A. Khalifa A.Abdel Moneim M.Abdel Azzem 《Journal of Electroanalytical Chemistry》1985,184(1):147-160
The electrochemical reduction of some fused ring systems containing four carbonyl moieties has been studied in alcoholic aqueous media. A mechanism has been proposed and clarified in which one carbonyl is reduced to a methylene group via an uptake of four electrons. 相似文献
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Primary amines bearing an α-hydrogen atom are quantitatively converted to symmetrical secondary amines by heating at 185°C for 5 h in the presence of a catalytic amount of RuCl2(Ph3)3. 相似文献
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The mixed halogen phases SrBrxI2?x, for which 2.00 > x > 0 were prepared both by heating weighed masses of pure SrBr2 and SrI2 in sealed evacuated quartz ampoules and by cocrystallization from absolute ethanol. The reaction products were examined by X-ray powder diffraction methods. Five distinct regions were observed in the phase diagram. The crystallographic characteristics of phases representative of the single phase regions, SrBr2SrBr1.60I0.40, SrBr1.40I0.60SrBr0.80I1.20, and SrBr0.30I1.70SrI2, are presented, and the anion distributions in the crystal structures are deduced on the basis of X-ray powder diffraction intensities. 相似文献
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Stanislaw A. Hodorowicz Ewa K. Hodorowicz Harry A. Elck 《Journal of solid state chemistry》1983,48(3):351-356
The variations in the lattice parameters in the BaBrxCl2?x system have been determined for the composition range 2.0 > x > 0.0. All phases exhibit the PbCl2-type orthorhombic structure and are assignable to space group Pnma. The crystallographic parameters of BaBrCl were determined by the Rietveld method from a line profile analysis of a digitized powder X-ray diffraction pattern. The anions are ordered with the bromide ion occupying the square pyramidal hole, and the chloride ion the smaller tetrahedral hole. Atomic coordinates are presented. 相似文献
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Franz Wochner Laszlo Zsolnai Gottfried Huttner Hans H. Brintzinger 《Journal of organometallic chemistry》1985,288(1):69-77
Ethylene-bridged titanocene and zirconocene derivatives with permethylated ring ligands, C2H4(C5(CH3)4)2TiCl2 and C2H4(C5(CH3)4)2ZrCl2, have been synthesized and their crystal structures determined. 相似文献
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Simple syntheses of calcium alkoxyalanates starting from NaAlH4, CaCl2 and alcohols involving evolution of hydrogen and separation of sodium chloride are reported. More complex methods, which allow the preparation of calcium alkoxyllalanates without loss of hydride hydrogen from NaAlH4, CaCl2, NaOR and AlX3 (X = OR, Cl) have also been developed. 相似文献
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The previously reported compounds VP4 and CoP2, prepared at high pressure, were synthesized in well-crystallized form at ambient pressure by reaction of the elemental components in the presence of iodine. Their structures were refined from single-crystal X-ray diffractometer data to conventional residuals of R = 0.033 for VP4 (CrP4 type structure, 11 variables, 815 F values) and R = 0.019 for CoP2 (arsenopyrite structure, 14 variables, 932 F values). VP4 is paramagnetic and a metallic conductor. CoP2 is a diamagnetic semiconductor with an activation energy of 0.34 eV. Chemical bonding and potential displacive phase transitions of these compounds are discussed. 相似文献
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N. Nakayama K. Kosuge S. Kachi T. Shinjo T. Takada 《Journal of solid state chemistry》1980,33(3):351-356
Magnetic susceptibilities of Ba2FeS3, Ba2CoS3, and Ba2MnS3 show rounded maxima at 130, 125, and 100 K, respectively, which are due to quasi-one-dimensional antiferromagnetic short-range ordering. Intrachain interactions, , are estimated to be ?20, ?15, and ?12 K, respectively. 57Fe Mössbauer spectra of Ba2FeS3 and 57Fe-doped Ba2CoS3 and Ba2MnS3 at 4.2 K show long-range antiferromagnetic ordering, due to the interchain interaction. The profile of Mössbauer spectra at 4.2 K is analyzed based on the coexistence of magnetic hyperfine and quadrupole interactions, and magnetic hyperfine fields at 4.2 K are estimated to be 36, 29, and 59 kOe, respectively. 相似文献
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Cobalt(I) carbonyl complexes of formula [Co(CO)n(P)5?n]ClO4 (n = 1, 2, 3; P = secondary or tertiary phosphine) have been prepared by reaction of CO under ambient conditions with Co(ClO4)2 · 6H2O and phosphine in isopropyl alcohol. The chemical and spectroscopic properties of these complexes are described and the stoichiometry and mechanism of the carbonylation reaction discussed. 相似文献
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Electron spin resonance (ESR) and magnetic-susceptibility measurements on the Li1+xTi2?xO4 spinel system () indicate the presence of two types of localized moments in this material. In both cases, an unpaired electron is trapped as a Ti3+ ion in a crystal field that is predominantly octahedral, but with a strong tetragonal component. This type of crystal field cannot arise in the stoichiometric spinel. We propose two types of defect in the title spinel system: an oxygen vacancy and a hydroxyl ion. Unpaired electrons are trapped as Ti3+ ions adjacent to these defects, and it is argued that the strong tetragonal field is associated with the formation of a static (TiO)+ ion by a displacement of the titanium ion from the defect. Spin relaxation occurs via a thermal ionization of the trapped electron that appears to be associated with a static-dynamic transition in the titanium-ion displacement. 相似文献