Koexistenzbeziehungen,Darstellung und Eigenschaften ternärer Phasen im System Cu/Mo/O

Coexistence Relations, Preparation and Properties of Ternary Compounds in the System Cu/Mo/O The phase diagram of the ternary system Cu/Mo/O is presented at 773 K. The compounds CuMoO₄, Cu₃Mo₂O₉, Cu₄Mo₅O₁₇, Cu₆Mo₅O₁₈, Cu_4–xMo₃O₁₂, and Cu_xMoO₃ are found to be thermodynamical stable. The homogeneity range of Cu_4–xMo₃O₁₂ runs to x = 0.1–0.2. Single crystals of CuMoO₄ and Cu₃Mo₂O₉ were grown by chemical transport reactions with TeCl₄, Cl₂, HCl, and Br₂ as transport agent. The results were compared with thermochemical calculations. The decomposition of CuMoO₄ and Cu₃Mo₂O₉ was investigated with thermal analysis and decompositon pressure measurements.     

Madaline网络用于分光光度法同时测定铜钴镍的研究

采用4－（2－吡啶偶氮）－间苯二酚（PAR）－Cu,Co,Ni显色体系，应用Madline神经网络原理，对于吸收光谱严重重叠的三组分金属配合物体系同时进行含量测定，Cu^2 ,Co^2 ,Ni^2 的平均回收率分别为94％，101％，102％，实验表明，该法具有训练速度快，预测结果准确度良好等特点，有望成为多组分分析的有效方法之一。     

Dissolution of copper foil in aqueous solution ofpH=2

The specific dissolution rate, expressed in mol cm^–2s^–1, and time-variation of the rest potential of copper foil in an aerated aqueous solution ofpH = 2.0 were measured.

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Die Auflösbarkeit von Kupfer-Folie in wäriger Lösung von pH 2 (Kurze Mitteilung)

Zusammenfassung Es wurde die spezifische Auflösungsgeschwindigkeit (in mol cm^–2s^–1) und die zeitliche Veränderung des Restpotentials von Kupfer-Folie in einer belüfteten wäßrigen Lösung von pH 2,0 gemessen.

     

Copper-catalyzed coupling of aryl halides and nitrite salts: a mild Ullmann-type synthesis of aromatic nitro compounds

Nitration of aromatic halides proceeded smoothly in the presence of catalytic amounts of Cu bronze and N,N′-dimethylethylenediamine. Sodium nitrite-18-crown-6, or tetra-n-butylammonium nitrite (n-Bu₄NNO₂) turned out to be efficient nitrating agents. The aromatic nitro compounds were synthesized under essentially neutral conditions.     

Interference of Copper(II) ions with Non-covalent Interactions in Uridine or Uridine 5′-Monophosphate Systems with Adenosine,Cytidine, Thymidine and their Monophosphates in Aqueous Solution

Coordination reactions of copper(II) ions and their effect on non-covalent interactions in uridine (Urd) or uridine 5′-monophosphate (UMP) systems with nucleosides (Ado, Cyd, Thd) and nucleotides (AMP and CMP) in aqueous solutions have been studied. At high pH the effective coordination centers are deprotonated N(3) atoms from Urd and Thd, whereas at low pH, the N(3) atoms of pyrimidine nucleosides are blocked for coordination and the metallation sites are endocyclic nitrogen atoms from Ado, Cyd, AMP and CMP. Moreover, at low pH, the main reaction center in nucleotide solutions is the phosphate group. The NMR study has proven the occurrence of non-covalent ion-dipole interactions and stacking interactions in the systems considered. Introduction of a copper ion in the majority of systems causes the disappearance of weak interactions between ligands. The structures of the complexes in solution have been inferred from the equilibrium study: an analysis of the pH range of their occurrence with respect to the pH range of deprotonation of particular groups in the compounds studied, using Vis, EPR and ¹³C as well as ³¹P NMR spectral analysis.     

Tandem asymmetric conjugate addition-enolacetates formation of enantiomerically enriched zinc and aluminium enolates

The metal enolates, resulting from the copper-catalyzed enantioselective conjugate addition of organometallic reagents (Et₂Zn or R₃Al) to cyclic and acyclic enones are quantitatively trapped as enolacetates with acetic anhydride.     

负载型非晶态Cu/SiO2催化剂的非晶性质

以超细ＳｉＯ２为载体，用ＫＢＨ４还原Ｃｕ＾２＋盐溶液制备了非负载型Ｃｕ和负载型Ｃｕ／ＳｉＯ２催化剂，ＸＲＤ，ＴＥＭ和电子衍射分析结果表明，负载型Ｃｕ／ＳｉＯ２为完全非晶态，而非负载型Ｃｕ中存在着少量晶态Ｃｕ，ＤＳＣ结果表明，非晶态Ｃｕ／ＳｉＯ２的热稳定性明显高于非负载型Ｃｕ，说明超细ＳｉＯ２具有稳定非晶结构的作用，ＸＰＳ结果表明，还原产物中的铜原子呈Ｃｕ状态，ＩＣＰ分析结果表明，样品中的Ｂ含量均低     

Regional distribution of manganese,iron, copper,and zinc in the rat brain during development

Manganese (Mn), iron (Fe), copper (Cu), and zinc (Zn) concentrations were determined in the brain regions of normal 1-, 3-, 5-, 7-, 14-, 21-, 42-, 77-, and 147-day-old Wistar rats using inductively coupled plasma mass spectrometry (ICP-MS), and their maps were illustrated in color to visually compare the distribution of the elements at various stages of the growth process. Sagittal slices (1-mm thickness) sectioned at the level of the substantia nigra were divided into 18 regions, and the small slice samples were digested in microwave-assisted closed vessels for ICP-MS measurement. Mn, Fe, Cu, and Zn concentrations increased region-specifically with age, and their distributional maps showed some characteristics. These findings are discussed in terms of needs for these trace elements in the normal brain. Among new findings about their brain distribution, it is especially noteworthy that higher concentrations of Mn, Fe, and Zn were observed in the substantia nigra compared with those in neighboring regions. The mapping method in this work is expected to open up possibilities for screening of the in vivo element–element interrelationships among these essential elements.     

Development of an Amperometric Sensor Highly Selective For Dopamine and Analogous Compounds Determination Using Bis(2,2′‐Bipyridil) Copper(II) Chloride Complex

The use of [Cu(bipy)₂]Cl₂?6H₂O as a biomimetic catalyst in the construction of an amperometric sensor for dopamine determination is reported. The sensor was prepared modifying a glassy carbon electrode with a Nafion membrane doped with [Cu(bipy)₂]Cl₂?6H₂O complex. The sensor presented a higher response in 0.25 mol L^?1 phosphate buffer solution (pH 7.0), with an applied potential of ?50 mV (vs. SCE). In the optimized operational conditions, a linear response range between 35 and 240 μmol L^?1, with a sensitivity of 2.02±0.07 nA l μmoL^?1 cm^?2 and detection limit of 8.0 μmol L^?1 were typically observed for the sensor. The response time presented for this sensor was 0.5 s, presenting the same response for at least 40 successive measurements, with good repeatability (3.0%) expressed as relative standard deviation for n=6. The difference of the response between four sensor preparations was 4%. A detailed investigation about the sensor response for other sixteen phenolic compounds and interfering species were carried out. The sensor was applied in the determination of dopamine in pharmaceutical preparation with success.     

Struktur‐ und magnetochemische Untersuchungen an KCuGaF6

Structural and Magnetochemical Studies on KCuGaF₆ The crystal structure of KCuGaF₆ was determined on the base of X‐ray single crystal data (wR₂ = 0.084 for 2476 independent reflections). The compound crystallizes with a = 728.56(4), b = 989.51(6), c = 676.27(3) pm, β = 93.120(5)°, Z = 4 in space group P2₁/c of the pyrochlore related KCuCrF₆ type. The octahedral coordinations [GaF₆] and [CuF₆] are slightly resp. strongly distorted (mean values Ga‐F: 188.2 pm resp. Cu‐F: 188.2/200.1/227.6 pm). The longest distances Ga‐F and the shortest ones Cu‐F are found within octahedral chains of these two kinds of atoms, running along [100] and [001], resp., and being mutually bridged as well (M‐F‐M in between 114 and 145°). The magnetic mole susceptibilities measured at powders and at a single crystal follow the isotropic Heisenberg model for S = ¹/₂, if effects of chain disrupture are considered in the form of some paramagnetic portion. No indication of threedimensional magnetic order is observed down to T = 2 K and low magnetic fields H < 100 G. KCuGaF₆ (J/k = —71 K for the powder) is distinguished this way from the chain structure compounds KCuAlF₆ und Na₂CuScF₇ (J/k = —76 resp. —59 K) which were also magnetically studied and yield similar antiferromagnetic exchange constants J/k.