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.     

新试剂5-(4-氯苯基偶氮)-8-苯磺酰氨基喹啉光度法测定微量铜

在 p H 8.5的 Na2 B4 O7- HCl介质及有氯化十六烷基吡啶 ( CPC)存在时 ,室温下铜 ( )与 5 - ( 4 -氯苯基偶氮 ) - 8-苯基磺酰氨基喹啉 ( CPBSQ)迅速反应 ,生成络合比为 1∶ 3的有色络合物。研究了反应的最佳条件 ,建立了一个测定 Cu( )的光度分析新方法。Cu( )的浓度在 0～ 1 4.0 μg/2 5 m L 范围内符合比耳定律 ,其摩尔吸光系数为 8.1 2× 1 0 4 L· mol- 1· cm- 1。方法用于面粉、茶叶及奶粉中铜的测定 ,其相对标准偏差为 0 .5 8%～ 1 .2 % ,标准加入回收率为 95 .5 %～ 1 0 4 .5 %。     

新显色剂1-羟基-2-(5-NO2-2-吡啶偶氮)-8-氨基-3,6-萘二磺酸与铜显色反应的研究

探讨了新显色剂 1-羟基-2-(5-NO2-2-吡啶偶氮)-8-氨基-3,6-萘二磺酸(简称5-NO2-PAH)与铜离子显色的适宜条件及其共存离子的影响,建立了 5-NO2-PAH测定铜的新显色反应体系.在 pH 7.0～10.0 范围内,铜与试剂形成稳定的 1∶2 配合物,其最大吸收峰位于 653 nm, 表观摩尔吸光系数εCu=4.68×104 L·mol-1·cm-1,铜的浓度在 0 μg/10 mL～14 μg/10 mL 范围内遵守比尔定律.方法已用于合金中铜的测定.     

Copper(II) tetrafluoroborate as a novel and highly efficient catalyst for Michael addition of mercaptans to α,β-unsaturated carbonyl compounds

Copper(II) tetrafluoroborate has been found to be a new and highly efficient catalyst for Michael addition of thiols to α,β-unsaturated carbonyl compounds under solvent-free conditions and in H₂O at room temperature. The reactions are very fast and are completed in 2 min to 1 h affording high yields. The rate of thiol addition was dependent on the steric hindrance at the β-carbon of the α,β-unsaturated carbonyl substrate. In the case of chalcones, the reactions are best carried out in MeOH as solvent.     

Characterization and properties of the copper(II/I) complexes of macrocyclic hexathiaether ligand [21]aneS6

The copper(II/I) complexes of hexathiaether macrocyclic ligand, 1,4,8,11,15,18-hexathiacyclohenicosane ([21]aneS₆), were synthesized, and characterized by electrochemical and spectroscopic techniques. Cyclic voltammetric studies indicate that Cu([21]aneS₆)^2+/+ forms a reversible one-electron redox couple. The electrochemical potential obtained for Cu([21]aneS₆)^2+/+ (E^f = 0.89 V, against SHE) was found to be the highest potential reported to date for a Cu^2+/+ macrocyclic system in aqueous solution. By employing the Nernst equation, we can infer that the practical upper limit for formal potential of Cu(II/I)L systems maybe close to this high value. Stability constant data obtained for these complexes indicate that Cu([21]aneS₆)⁺is 12 orders of magnitude greater in stability than that of Cu([21]aneS₆)²⁺ indicating the favorable nature of this large macrocyclic ligand towards formation of Cu(I) complexes over Cu(II) complexes. Crystal structure of Cu([21]aneS₆)⁺ ( Fig. 2) shows that four sulfurs adjacent to one another are coordinated to Cu⁺ ion in this complex. Bond angles and distances calculated for the crystal indicate that it is a distorted tetrahedron, a geometry commonly encountered by Cu(I) complexes. This is the first report of synthesis and characterization of a metal coordinated [21]aneS₆ complex.     

Alkali Cation Ligating Chains and Sheets of the Macrocycle 1, 7‐Dithia‐18‐Crown‐6 with Bridging Iodo‐ and Thiocyanatocuprate(I) Units

Treatment of an acetonitrile solution of CuI with 1, 7‐dithia‐18‐crown‐6 (1, 7‐DT18C6) at 100°C affords the coordination polymer ¹[(CuI)₂(1, 7‐DT18C6)₂] ( 1 ) in which 1, 7‐DT18C6 ligands bridge (CuI)₂ rings into double chains. 1D polymers of the type ¹[M{(Cu₃I₄)(1, 7‐DT18C6)}] (M = K, 2 ; M = Cs, 3 ) can be isolated under similar conditions in the presence of respectively KI and CsI. Both contain bridging heptacyclic [Cu₆I₈]^2— units but crystallise in different space groups, namely P1 and C2/m. The cesium cation of 3 is markedly displaced from the best plane through the thiacrown ether donor atoms. Reaction of 1, 7‐DT18C6 with CuSCN in the presence of NaSCN yields ²[{Na(CH₃CN)₂} {(CuSCN)₂(1, 7‐DT18C6)}][Cu(SCN)₂] ( 4 ), in which ¹[(CuSCN)₂] double chains are linked through macrocycles into sheets. Infinite ¹[{Cu(SCN)₂}^—] chains compensate the charge of the Na⁺ cations. Complex 1 can imbibe 0.90 mol CsNO₃ per mol of 1, 7‐DT18C6 pairs.     

Coordination properties of 6-deoxy-6-[1-(2-amino) ethylamino]-β-cyclodextrin and the ability of its copper(II) complex to recognize and separate amino acid enantiomeric pairs

The functionalized cyclodextrin 6-deoxy-6-[1-(2-amino)ethylamino]--cyclodextrin was synthesized, and an NMR, EPR, pH-metric, and calorimetric investigation was carried out in aqueous solution in order to ascertain its behaviour towards protonation and copper(II) complex formation. The thermodynamic parameters of the ternary complex formation with alanine, phenylalanine and tryptophan enantiomeric pairs were also determined (25° C andI=0.1 mol dm^–3). No thermodynamic enantioselectivity was observed in these systems, while a chiral, though poor, discrimination was observed in LEC: c.d. spectra also show enantiomeric stereoselectivity. The results of the present investigation, compared with previously reported results, suggest the occurence of acis-complex trans-complex equilibrium in such systems.