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1.
A simple and rapid method for the analysis of trace amounts of gold(III), palladium(II), and platinum(IV) by the combined use of graphite furnace atomic absorption spectrometry and anion-exchange separation was proposed, and successfully applied to the rapid determination of metals in industrial waste solutions obtained from the final process of noble-metal recovery factories, because noble metals can be selectively and quantitatively separated to a high degree by using a small column containing only a 0.7 g-portion of a common anion-exchange resin and a dilute thiourea solution. 相似文献
2.
Keiichiro Fukumoto Masatoshi Chihiro Yuichi Shiratori Masataka Ihara Tetsuji Kametani Toshio Honda 《Tetrahedron letters》1982,23(29):2973-2976
Thermolysis of a benzocyclobutene derivative () prepared from norcamphor produced stereoselectively a tetracyclic compound (), which was converted to a lactone () having correct stereochemistry at C7, C8, C9, C11, C13, and C14 positions of (±)-klaineanone. 相似文献
3.
Masanori Yamaguchi Kaoru Kojima Ikuko Kakizaki Keiichi Takagaki 《Tetrahedron letters》2006,47(42):7455-7458
Efficient constructions of two types of neo-proteoglycan are described. Enzymatically prepared alkyne containing chondroitin 6-sulfate chains and chemically synthesized azido group having compounds are linked by utilizing the copper(I) catalyzed 1,3-dipolar cycloaddition. 相似文献
4.
Tanaka H Yamada T Sugiyama S Shiratori H Hino R 《Journal of colloid and interface science》2005,286(2):812-815
Using a hydroxyl group appended free base porphyrin derivative (HP), porphyrin-introduced silica gels were synthesized by a sol-gel process. The HP content in the materials linearly increased with increasing the HP concentration. Meanwhile, free base tetraphenylporphyrin (TPP) with no hydroxyl groups were almost not incorporated into the silica gels. These facts suggested that the interaction between hydroxyl groups of the HP molecules and silica network is considerably strong. The UV-vis characters of HP-introduced materials were almost the same as pure HP molecules. The Beer's plot indicated that the HP molecules in the materials are dispersed. 相似文献
5.
Inorganic-organic hybrids have been synthesized by incorporation of the inorganic component of Ti(OC2H5)4 into the organic polymer of ethyl cellulose. The inorganic-organic hybrids did not dissolve in toluene used as a solvent for the starting materials. The ethanol was formed as a by-product of the alcoholysis condensation reaction between Ti(OC2H5)4 and ethyl cellulose. These results suggest that ethoxy groups of Ti(OC2H5)4 react with hydroxy groups of ethyl cellulose to form cross-linking bonds of –O–Ti–O–. The reaction of Ti(OC2H5)4 with ethyl cellulose was further investigated by Fourier transform infrared (FT-IR) spectroscopy. The FT-IR spectroscopic experiments revealed that the Ti–O bond state of Ti(OC2H5)4 was changed by refluxing a toluene solution of Ti(OC2H5)4 with ethyl cellulose. The inorganic-organic hybrids have an interesting dielectric property; their dielectric constant is higher than that of ethyl cellulose and that of a simple mixture of TiO2 and ethyl cellulose. 相似文献
6.
Shigeo Iwayanagi Ikuko Sakurai Tosio Sakurai Tsuneo Seto 《Journal of Macromolecular Science: Physics》2013,52(2):163-177
The crystal structure of trans-1,4-polybutadiene has been reported by Natta et al. to be pseudo-hexagonal below its solid-phase transition temperature. In the present X-ray structure analysis, it is revealed that the crystal belongs to the monoclinic system with the space group P21/a. The unit cell, with the lattice constants a = 8.63 Å, b = 9.11 Å, c = 4.83 Å, and β = 114°, includes four molecular segments. 相似文献
7.
8.
Upon visible-light irradiation, reductive carboxylation of alkyl halides takes place by using a SmI2/Sm mixed system under atmospheric CO2 to afford the corresponding carboxylic acids in good to excellent yields. 相似文献
9.
Ikuko Mori Miyuki Ukachi Kimiyo Nagano Hiroyasu Ito Jun Yoshinaga Masataka Nishikawa 《Analytical and bioanalytical chemistry》2010,397(2):463-470
A candidate environmental certified reference material (CRM) for the determination of multielements in tea leaves and materials
of similar matrix, NIES CRM No. 23 Tea Leaves II, has been developed and characterized by the National Institute for Environmental
Studies (NIES), Japan. The origin of the material was tea leaves, which were ground, sieved through a 106-μm mesh, homogenized,
and then subdivided into amber glass bottles. The results of homogeneity and stability tests indicated that the material was
sufficiently homogeneous and stable for use as a reference material. The property values of the material were statistically
determined based on chemical analyses by a network of laboratories using a wide range of methods. Sixteen laboratories participated
in the characterization, and nine certified values and five reference values were obtained. These property values of the candidate
CRM, which are expressed as mass fractions, were close to the median and/or mean values of the mass fractions of elements
in various tea products. The candidate CRM is appropriate for use in analytical quality control and in the evaluation of methods
used in the analysis of tea and materials of similar matrix. 相似文献
10.
The empirical energy parameters for a calcium ion and its ligands in proteins were determined within a pairwise additive framework. The interaction energies of Ca2+-water, Ca2+-peptide group and Ca2+-carboxyl group systems were calculated using the ab initio molecular orbital method with basis sets of double zeta quality including polarization or diffuse functions. The resulting potential energy surfaces served as references for the determination of the nonbonded parameters in the empirical energy function. The nonadditive corrections for the Ca2+-ligand pair potentials are incorporated implicitly in the nonbonded paremeters by treating three-body (1:2 complex) or seven-body (1:6 complex) systems in reference calculations. Ligand polarizations induced by Ca2+ are estimated from the partial atomic charges of two-body (1:1 complex) systems. The charge sets were determined by scaling so as to reproduce the reference potential energy surfaces. The newly determined parameter set was used in a stochastic boundary molecular dynamics simulation of phospholipase A2. The solvated structure of the Ca2+-binding site obtained from an X-ray crystallographic study is well reproduced by the parameter set. 相似文献