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41.
Carbonate Isostructural Anions [SnX3]5? in the Compounds Rb6[SnX3]O0.5 and Cs6[SnX3]O0.5 with X = As, Sb, and Bi The metallic shining compounds Rb6[SnX3]O0.5 and Cs6[SnX3]O0.5 with X = As, Sb, and Bi were prepared from the melt starting from adequate mixtures of the elements and SnO2. They crystallize in the hexagonal system (space group P63/mmc, No. 194, Z = 2) with the lattice constants mentioned in ?Inhaltsübersicht”?. In the structures of the isotypic compounds tin and the main group(V) elements build up trigonal planar anions [SnX3]5? with X = As, Sb, and Bi isostructural to the carbonate anion, oxygen forms isolated O2? ions. The bond lengths Sn? X are significantly shortened with respect to the sums of Pauling covalent radii. The atoms of the units [SnX3]5? are coordinated by alkali metal cations forming trigonal prisms and the O2? anions occupy octahedral holes. 相似文献
42.
Single Crystal Investigations on Fluoroperovskites MPdF3 (M = Rb, K) and PdF2 Single crystal investigations on PdF2 (violet) confirm the tetragonale rutile structure [1, 2] with a = 495.44(3) pm, c = 338.48(3) pm, Z = 2, space group P42/mnm-D (No. 136) (xF = 0.3058(8)). RbPdF3 and KPdF3 have been obtained. RbPdF3 and KPdF3 both ruby-red single crystals crystallize cubic (perovskite-structure), space group Pm3m-O (No. 221) with a = 429.41(8) pm (RbPdF3) respectively a = 424.30(4) pm (KPdF3). 相似文献
43.
制备和表征了一种新的酞菁键合硅胶,三-β-(辛巯基)-β-(磺酰胺基)-酞菁铜键合硅胶。研究了该键合酞菁硅胶作为HPLC固定相的基本色谱性能。实验结果表明,该固定相可以分离四-α-(2,2,4-三甲基-3-戊氧基)酞菁(铜、镍)的4种异构体,也可以观察到四-α-(2,2,4-三甲基-3-戊氧基)无金属酞菁的4种异构体,而商业C18(VERTEX Eurospher)却只能观察到两组峰,表明这种酞菁键合硅胶固定相在分析、分离一些取代酞菁异构体方面比商业C18具有更好的分离效果。 相似文献
44.
According to the new method of preparing core-shell nanospheres developed by our group, by using two monomers, 2-hydroxypropyl
methacrylate(HPMA) and vinyl acetate(VAc), two kinds of core-shell nanospheres with poly(ɛ-caprolactone) (PCL) as the core
and crosslinked poly(2-hydroxypropyl methacrylate) (PHPMA) or poly(vinyl acetate) (PVAc) as the shell were successfully prepared
under similar conditions. After degrading the PCL cores of the two kinds of nanospheres by lipase, the corresponding crosslinked
poly(methyl acrylic acid) hollow spheres and crosslinked poly(vinyl alcohol) hollow spheres were obtained. Results indicate
that the new method we proposed for preparing core-shell polymeric nanospheres via in-situ polymerization can be generalized to a certain extent, and it is suitable for many systems provided the monomer used is soluble
in water, while its corresponding polymer is insoluble in water.
Translated from Chemical Journal of Chinese University, 2006, 27(9): 1762–1766 [译自: 高等学校化学学报] 相似文献
45.
Eckhard Herrmann Moein Nouaman Zdirad
k Gisbert Großmann Gisela Ohms 《无机化学与普通化学杂志》1994,620(11):1879-1888
Tetraarylesters of μ-Imido-Diphosphoric Acid and its Thio Derivatives — Structure Investigations New O,O′,O″,O?-tetratolyl- and ditolyl-diphenylesters of the μ-imido-diphosphoric acid and its mono and dithio derivatives were synthesized, compared with the corresponding tetraphenylesters and investigated by 1H, 13C, and 31P NMR spectroscopy and X-ray crystal structure analysis. Structures of the O,O′,O″,O?-tetrakis-(2-methyl-phenyl)-μ-imidodiphosphate, 1b , as well as of the corresponding ortho-, meta- and para-tolylesters of the μ-imido-monothiodiphosphoric acid ( 2a , 2b , 2c ) were determined. All the compounds form dimers via N? H…?O hydrogen bonds in the crystal as well as in nonpolar solvents. The distances around the phosphorus atoms rise with decreasing electronegativity of the phosphorus substituents. Signs of the 2JP? N? P coupling constants were determined by 13C{1H, 31P} triple resonance experiments for some compounds. These constants become more negative owing to substitution of a phosphoryl by a thiophosphoryl group. 相似文献
46.
This report describes the determination of paraquat (PQ) in human blood plasma samples by a direct-injection reversed-phase ion-pair chromatographic method. Blood plasma filtrate was injected directly into the LiChrospher® RP-18 alkyl-diol silica (ADS) precolumn integrated in a column switching system using a mixture of 3% 2-propanol and 10 mM sodium octane sulfonate (SOS) in a 0.05 M phosphate buffer (pH 2.8). After washing with this phase, the ADS precolumn was back-flushed with the analytical mobile phase consisting of 40% of methanol and 10 mM SOS in a 0.05 M phosphate buffer (pH 2.8) at a flow rate of 1.0 ml min−1, in order to carry the analyte to a conventional reversed-phase analytical column, where the separation of PQ was achieved and finally detected by UV at 258 nm. The recoveries of PQ from human blood plasma samples ranged between 95.0 and 99.5% at nine different concentrations (from 0.05 to 3.00 μg of PQ ml−1) with coefficients of variation <2.5% (n=3). The precision expressed as relative standard deviation was below 3.5% for between-day and below 4.3% for within-day measurements (n=5). The detection limit (signal-to-noise ratio, S/N>3) was 0.005 μg ml−1 with an injection volume of 200 μl. The proposed method is promising for the identification and quantification of PQ at low concentration levels and is suitable for its analysis in human blood plasma samples from intentional or accidental poisonings cases with a sample throughput of 5 samples per hour. 相似文献
47.
Katsunori Teranishi 《Journal of inclusion phenomena and macrocyclic chemistry》2002,44(1-4):313-316
A useful technique to bifunctionalize the secondary hydroxyl faces of cyclodextrins is described. Regioselective2A,2D-disulfonylations ofcyclodextrins were achieved by reacting cyclodextrins with a combinationof a novel disulfonyl imidazole reagent and molecular sieves inN,N-dimethylformamide. The resulting disulfonates were convertedto 2A,3A,2D,3D-dimannoepoxy-cyclodextrins and3A,3D-diamino-3A,3D-dideoxy-(2AS,3AS),(2DS,3DS)-cyclodextrins, which contain twofunctional groups on the periphery of the molecules. 相似文献
48.
氯化钪-氯化钠-氯化钾熔盐制备新工艺研究 总被引:3,自引:1,他引:3
研究了以Sc2O3为原料,盐酸回流溶解后与NaCl,KCl,NH4Cl溶液混合,经蒸发浓缩、结晶、真空预脱水,再在氩气保护下分段升温脱水、升华除去过量NI-hCl后制备ScCl3-NaCl-KCl熔盐的新工艺。研究表明,添加NH4Cl后加热脱水时,NH4Cl分解产生的HCl气体能抑制ScCl3水合物加热过程中的水解,溶解产生的水不溶性钪,从而有效地防止了Sc2O3等水不溶化合物的生成。制备的ScCl3-NaCl-KCl熔盐脱水完全、水不溶性钪含量很低,能满足熔盐金属热还原法制备金属钪及铝钪中间合金对熔盐原料的要求。 相似文献
49.
[Rb2(H2O)2][Re3(μ-Cl)3Br7(H2O)2]2 · H2O, a Mixed Halide-Hydrate with the Anionic Dimer {[Re3(μ-Cl)3Br7(H2O)2]2 · H2O}2? [Rb2(H2O)2][Re3(μ-Cl)3Br7(H2O)2]2 · H2O crystallizes as dark redbrown single crystals from an hydrobromic-acid solution of ReCl3 and RbBr at 0°C. An important feature of the crystal structure (monoclinic, C2/c; a = 1494.61(8); b = 835.71(4); c = 3079.96(19) pm; β = 97.801(4)°; Vm = 573.9(4) cm3mol?1; R = 0.060; Rw = 0.038) is the connection of two anions [Re3(μ-Cl)3Br7(H2O)2]? via a water molecule to dimers, {[Re3(μ-Cl)3Br7(H2O)2]2 · H2O}2?. These dimeric units are contained in slabs that are stacked in the [001] direction and held together by Rb+ cations and crystal water. 相似文献
50.
The title compound ist the first example of an adduct between telluric acid and the twenty four membered ring anion of a cyclododecaphosphate. [C(NH2)3]12P12O36 · 12 Te(OH)6 · 24 H2O crystallizes trigonal (rhomboedral: R3) with Z = 3 and the unit-cell dimensions a = 15.854(9), c = 51.26(2) Å in the hexagonal setting. The crystal structure was solved by direct methods and refined to a final R value of 0.031. It is characterized by a succession of three different typs of alternating layers perpendicular to the c direction. This layers are connected only by hydrogen bonds. The individual layers are built up of A: P12O36 anions, guanidinium cations and water of crystallisation, B: hexagonal arranged Te(OH)6 groups and guanidinium cations and C: water of crystallization. 相似文献