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221.
Epimerization of d-glucose and d-mannose, catalyzed by the water soluble complexes of Cu(II), Ni(II), Co(II) and Cd(II) with bisnitrogen ligands 4–7, and by Mo(VI) complexes prepared in situ from ammonium heptamolybdate (AHM) with ligands 4–9 is compared. All examined complexes exhibit lower catalytic activity than AHM: strong coordination of the ligands by both (N,O) heteroatoms to metal ions, presumably affords catalytically less active species. Some free ligands and their metal (II) complexes catalyze both C(2) epimerization and isomerization of aldoses to d-fructose. 相似文献
222.
Ionel Haiduc Gellert Mezei Rodica Micu‐Semeniuc Frank T. Edelmann Axel Fischer 《无机化学与普通化学杂志》2006,632(2):295-300
The three (O‐methyl)‐p‐ethoxyphenyldithiophosphonato triphenylphosphine complexes of copper, silver and gold, [(Ph3P)nM{S2P(OMe)C6H4OEt‐p}] (M = Cu, n = 2; M = Ag, Au, n = 1) investigated structurally by X‐ray diffraction exhibit remarkable structural differences. The copper compound is a four‐coordinate chelate monomer with Cu–S 2.4417(6) and 2.5048(6) Å; P–Cu–S 104.24(2)–114.01(2)°; Cu–S–P 82.49(3)° and 80.85(2)°. The silver compound is a cyclic dimer with bridging dithiophosphonato ligands and three‐coordinate silver atoms [Ag–S 2.5371(5) and 2.6867(5) Å; P–Ag–S 122.88(2)° and 122.17(2)°; Ag–S–P 89.32(2)° and 103.56(2)°]. The gold compound is monomeric with linear dicoordinate gold [Au–S 2.3218(6) Å; P–Au–S 177.72(2)°, Au–S–P 100.97(3)°]. 相似文献
223.
Polycrystalline Cu3P was successfully prepared under a wide variety of solvothermal conditions. The reaction of red phosphorus with several copper sources (copper metal, copper (I) iodide, copper (I) chloride and copper (II) chloride) at 150-200 °C for 1-2 days in water produced Cu3P. Products were examined with powder X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy. Thermal analyses and optical spectroscopy were also performed. A detailed list of reaction conditions, products and impurity phases (where applicable) are reported. 相似文献
224.
《Electroanalysis》2005,17(17):1589-1594
Simultaneous determination of bismuth and copper by anodic stripping voltammetry using H‐point standard addition method (HPSAM) with simultaneous addition of analytes is described. The effect of various parameters including acid concentration, accumulation time, accumulation potential and concentration ratio of analytes in the standard solution on the sensitivity and accuracy of method were investigated. The results of applying the H‐point standard addition method showed that Cu2+ and Bi3+ could be determined simultaneously with the concentration ratios of Cu2+ to Bi3+ varying from 1 : 15 to 16 : 1 in the mixed sample. The method was successfully applied to the simultaneous determination of copper and bismuth in some synthetic mixtures. 相似文献
225.
Single crystals of {[Cu(TO)2(H2O)2](NO3)2}n (TO: 1, 2, 4‐triazol‐5‐one) were grown by slow evaporation from aqueous solution. It crystallizes in the orthorhombic space group Pbca, with a = 7.082(1), b = 10.285(1), c = 17.911(3)Å, V = 1304.6(3)Å3, Z = 4. The CuII distorted octahedra are bridged by bidentate TO ligands into infinite 2‐D interlaced rhombic grid‐like network planes, {[Cu(TO)2(H2O)2]2+}n. Hydrogen bonds, electrostatic interactions, and weak van der Waals' forces assemble these planes and the NO3— anions to a layered structure. The title compound decomposes at 153.4 °C to the final products, Cu(CN)2 and CuO. 相似文献
226.
Denilson S.S. dos Santos Alete P. Teixeira José T.P. Barbosa Sérgio L.C. Ferreira Maria das Graças A. Korn Leonardo S.G. Teixeira 《Spectrochimica Acta Part B: Atomic Spectroscopy》2007
In this work, the use of cetyltrimethylammonium bromide as surfactant for the preparation of oil-in-water emulsions for the determination of Cu and Cr in gasoline by electrothermal atomic absorption spectrometry (ET AAS) was evaluated. The surfactant amount was tested in the range of 25 to 300 mg, added to 2 ml of gasoline, and completed to 10 mL with 0.1% (v/v) nitric acid solution. 150 mg of surfactant was found optimum, and a sonication time of 10 min sufficient to form an oil-in-water emulsion that was stable for several hours. The ET AAS temperature program was established based on pyrolysis and atomization curves. The pyrolysis temperatures were set at 700 and 1300 °C for Cu and Cr, respectively and the selected atomization temperatures were 2400 and 2500 °C. The time and temperature of the drying stage and the atomization time were experimentally tested to provide optimum conditions. The limits of detection were found to be 5 μg L− 1 and 1.5 μg L− 1 for Cu and Cr, respectively in the original gasoline samples. The relative standard deviation (RSD) ranged from 4 to 9% in oil-in-water emulsions spiked with 5 μg L− 1 and 15 μg L− 1 of each metal, respectively. Recoveries varied from 90 to 98%. The accuracy of the proposed method was tested by an alternate procedure using complete evaporation of the gasoline sample. The method was adequate for the determination of Cu and Cr in gasoline samples collected from different gas stations in Salvador, BA, Brazil. 相似文献
227.
Rosa Ortiz Joaquín Borrás Lourdes Perelló Horacio Jimenez 《Monatshefte für Chemie / Chemical Monthly》1986,117(4):443-451
The formation constants of the binary complexes Cu(CM)2+ and Cu(CM)
2
2+
as well as those of the ternary complexes Cu(CM)L
+ and Cu(CM)2
L
+ (CM=Cimetidine=N-Cyano-N-methyl-N[(5-methyl-1H-imidazol-4-yl)methyltioethyl]-guanidine; HL=Phenobarbital=5-ethyl-5-phenyl-barbituric acid) have been determined in 0.1 and 1.0 mol dm–3 NaClO4 methanol solutions at 25±0.2°C. The values of logX, log stat.., and logK confirm the stability of the ternary complexes.
Ternäre Komplexe von Cimetidin und Phenobarbital mit Cu(II) in methanolischer Lösung
Zusammenfassung Die Stabilitätskonstanten der binären Komplexe Cu(CM)2+ und Cu(CM) 2 2+ sowie die der ternären Komplexe Cu(CM)L + und Cu(CM)2 L + (CM=Cimetidin=N-Cyan-N-methyl-N-[(5-methyl-1H-imidazol-4-yl)methylthioethyl]-guanidin; HL=Phenobarbitalum=5-Ethyl-5-phenyl-barbitursäure) wurden in 0.1 und 1.0M Lösungen von NaClO4 in Methanol bei 25±0.2°C bestimmt. Die Werte von logX, log stat. und logK bestätigen die Stabilität der ternären Komplexe.相似文献
228.
1-Amino-3-methoxypropane (3MPA) and 2-dimethylaminoethanol (DMAE) are potential volatile amines for boiler water treatment and were investigated for their complexation behaviour with copper. Their pKb values were 3.67 and 4.52 at 25°C and they formed coloured complexes with absorption in the region of 644 and 510 nm, respectively. In the pH range 10–11, the Cu-3MPA complex exhibited stepwise reduction and [Cu(3MPA)2]+ was identified, with a stability constant of 109.52. In the pH range 8–10.5, the Cu-DMAE complex exhibited 2e? reduction and the species [Cu(DMAE)2(OH)2] was identified, with a stability constant of 1020.39. A correlation between visible and ESR spectra and reduction behaviour was established. 相似文献
229.
Synthesis and characterization of PVP/AAc copolymer hydrogel and its applications in the removal of heavy metals from aqueous solution 总被引:1,自引:0,他引:1
Chelating poly(vinylpyrrolidone/acrylic acid) (PVP/AAc) copolymer hydrogels were prepared by radiation-induced copolymerization. The effects of preparation parameters such as PVP content in the hydrogel and irradiation dose on the swelling behavior of the hydrogel were studied. The pH dependent swelling was investigated. The thermal stability of the prepared hydrogel and the metal chelated ones was characterized by TGA. The removal of Fe(III), Cu(II), and Mn(II) from aqueous solution by the prepared PVP/AAc chelating hydrogel was examined by batch equilibration technique. The influence of treatment time, pH, and the initial feed concentration on the amount of the metal ions removed was studied. The results show that the removal of the metal ion followed the following order: Fe(III) > Cu(II) > Mn(II). The amounts of the removed metal ions increased with treatment time and pH of the medium. To re-use the hydrogel, the metal ions were stripped by using 2 N HCl. 相似文献
230.
116例冠心病患者血清中铜铬锰钴镍钒含量的探讨 总被引:1,自引:0,他引:1
测定了116例冠心病患者血清中铜、铬、锰、钴、镍、钒的含量并与正常值比较,显示含量升高才是有铬和镍,降低者有钴和钒、无差异者有铜和锰。 相似文献