ESR and optical spectra of Cu2+:NH4Br

ESR and optical studies of Cu²⁺ ions doped in NH₄Br single crystals have been carried out at room temperature. A new centre has been identified for the crystal grown from acidic medium. The room temperature data reveal that Cu²⁺ ions go to interstitial sites having square planar coordination of four Br^? ions.     

The influence of Ni2+ lons on the distribution of Mg2+ and Cu2+ lons in spinel ferrites

Cation distribution in quenched and furnace-cooled samples of composition Ni_xM_1?xFe₂O₄ (where M is either Mg²⁺ or Cu²⁺) has been studied through magnetization measurements. It has been found that cation distribution in these mixed ferrites cannot be predicted by site preference energies. In magnesium-nickel ferrites, cation distribution is controlled by heat treatment up to x = 0.5, beyond which the effect of heat treatment diminishes. Addition of Ni²⁺ ions in copper ferrite reduces the diffusibility of Cu²⁺ ions and the distribution tends toward inverse spinel in the high-nickel region.     

Die Titration von Ag+ und Cu2+

Ohne Zusammenfassung     

Die quantitative Abtrennung des Cu2+ von Mg2+, Sr2+ und Ba2+

Ohne Zusammenfassung     

Nonempirical quantum-chemical studies on Cu+ carbonyl and isocarbonyl complexes

Nonempirical quantum-chemical calculations with the double-zeta basis set have been performed for the Cu⁺ complexes with one, two, and four CO molecules having carbonyl, isocarbonyl and -bridged structures.

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Cu⁺ , CO. , - .

     

Durch elektrochromatographische Untersuchung der komplexen Laurate von Co2+, M2++ und Cu2+

Ohne Zusammenfassung     

Kinetics of Fe3+ and Cu2+ sorption by fibrous polyampholite

The kinetics of Fe³⁺ and Cu²⁺ sorption from sulfate salt solutions by fibrous polyampholite have been studied.

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Fe³⁺ Cu²⁺ , .

     

Enthalpies of ligation of Co2+ and Cu2+ to epimeric threonines and isoleucines

The enthalpies of protonation of epimeric threonines and isoleucines were determined calorimetrically at 298.15 K in 0.1 mol dm^?3 NaNO₃. The enthalpies of ligation of the same ligands with Co²⁺ and Cu²⁺ were determined under the same conditions.     

The sodium hyperfine splitting constant for the Na+Furil⨪Na+ triple ion

The small magnitude and positive sign of the sodium atom hyperfine splitting constant of the Na⁺furil^? radical triple ion is interpreted by elementary MO arguments. The model gives some insight into the nature of the Na—O coordination in such species.     

Optical absorption and emission spectra of Cu+ : NaF single crystals

The optical absorption spectrum of monovalent copper in single-crystal sodium fluoride to 1300 Å, and its emission spectrum is reported. The temperature dependence of the observed bands shows that Cu⁺ is on-center in NaF.     

Multiple scattering method applied to the electronic structure and spectra of the impurity ions Cu2+, Ni2+, Co2+, Fe2+ and their tetrahedral environments in ZnO,ZnS and CdS

The multiple scattering method with local exchange and muffin-tin potentials is applied to tetrahedral clusters with Cu²⁺, Ni²⁺, Co²⁺ and Fe²⁺ as central ions and oxygen and sulphur as ligands. The calculated orbital energy differences ?(t₂^*) - ?(e^*) are compared to Δ_t values deduced from optical spectra. The agreement is fairly good.     

罗丹明B衍生物的合成及其对Cu2+,Hg2+的识别研究

以罗丹明B-酰肼和2-羟基-3-喹啉醛缩合反应得到新型罗丹明B衍生物L,其结构经1H NMR,MS及元素分析表征.通过紫外光谱法和荧光光谱法研究了目标物L在CH3CN-H2O溶液中与金属离子的识别特性.结果表明:目标物L作为探针可选择性比色识别Cu2+和荧光识别Hg2+.随着Cu2+或Hg2+的滴加,探针L的内酰胺环结构发生开环,并形成L-Cu2+1∶1配合物或L-Hg2+1∶2配合物,识别过程均是可逆的.     

Potentiometrische Bestimmung von Silber mit KJ in Gegenwart von Fe3+, Zn2+, Pb+, Cu2+ und Ni2+

Ohne Zusammenfassung     

An alternative interpretation of the “anomalous” positive g∥-shift observed for NH4I: Cu2+

It is shown that the positive g_∥-shift observed for two centers in NH₄I : Cu²⁺ with compressed octahedral geometry can be reasonably understood within a molecular orbital picture for a true C_4v complex. Following this explanation, which discards the vibronic admixture mechanism proposed by Chand and Upreti, the positive g_∥ - g₀ value arises from a charge-transfer contribution to g_∥ - g₀ similar to that of d⁷ ions in strong-field situations.     

Electrochemical production of NH2• radicals by the system Cu2+/VO2+/NH2OH and their reactions with benzene and toluene

Electroinitiated production of NH₂^. radicals was demonstrated to occur in aqueous acid solution when in the system Cu²⁺/VO²⁺/NH₂OH Cu²⁺ is reduced to metallic copper on a mercury cathode. The first stage of this process involves the reduction of vanadyl to V³⁺ by metallic copper. The electrochemical system Cu²⁺/VO²⁺ was demonstrated to follow a depolarization scheme of the type of the catalyzed electrode process.For the reaction Cu+2 VO²⁺k₁→Cu²⁺+2 V³⁺ a k₁ value of 32 M^?1 s^?1 at 50°C was calculated.The second stage of the process is the reduction of NH₂OH by V³⁺ to give aminyl radicals. In presence of benzene and toluene these radicals add to the aromatic ring to give new radicals which are oxidized by Cu²⁺ to the corresponding amines.The cuzrent yield of this process attains values as high as 70%. The yield dependence on H₂SO₄ concentration, electrolytic current and dioxane concentration is discussed.     

含萘酚直链多胺化合物的合成及对Cu2+的识别

以β-萘酚为原料合成了两种含萘酚直链多胺化合物,并用IR、1H NMR、Ms进行了表征。利用紫外分光光度法考察了这两种化合物对金属阳离子的识别性能。实验结果表明,这两种化合物均对Cu2+具有高选择性识别能力,说明在主客体识别中分子尺寸的匹配和化合物中基团的空间合理排布是化合物和Cu2+间能发生相互作用的重要根据。     

Molecular structure and character of bonding of mono and divalent metal cations (Li+, Na+, K+, Mg2+, Ca2+, Zn2+, and Cu+) with guanosine: AIM and NBO analysis

The B3LYP/6-311++G (d,p) density functional approach was used to study the gas-phase metal affinities of Guanosine (ribonucleoside) for the Li⁺, Na⁺, K⁺, Mg²⁺, Ca²⁺, Zn²⁺, and Cu⁺ cations. In this study we determine coordination geometries, binding strength, absolute metal ion affinities, and free energies for the most stable products. We have also compared the results for Guanosine, with our previously reported results for 2′-Deoxyguanosine. Based on the results, it is obvious that MIA is strongly dependent on the charge-to-size ratio of the cation. Guanosine interacts more strongly with Zn²⁺ than do with Mg²⁺, Ca²⁺, and Cu⁺ and therefore stronger interactions lead to higher MIA. In both free molecules and their complexes, the Syn orientation of the base is stabilized by an intramolecular O5′–H···N3 hydrogen bond and the anti orientation of the base is stabilized by an intramolecular C–H···O hydrogen bond formed between the (C8-H8) and the O5′ atom of the sugar moiety. It is also interesting to mention that linear correlation between calculated MIA values and the atomic numbers (Z) of the metal ions of Li⁺, Na⁺, and K⁺ were found. Furthermore, the influences of metal cationization on the strength of the N-glycosidic bond, torsion angles, angle of pseudorotation (P), and intramolecular C–H···O and O–H···O hydrogen bonds have been studied. Natural bond orbital (NBO) analysis was performed to calculate the charge transfer and natural population analysis of the complexes. Quantum theory of atoms in molecules (QTAIM) was also applied to determine the nature of interactions.     

Hydration of the ions Al3+ and Cu2+. An ab initio SCF study

Ab initio calculations are reported for the systems Al(H₂O)_n³⁺ and Cu(H₂O)_n²⁺ with n up to 7. The calculated binding energies increase monotically up to n = 6, with equal binding energies for n = 6 and 7 for the Al³⁺ cation. An estimate of the enthalpy of hydration of Al³⁺ is given, based on model calculations with one or two water molecules from the second solvation shell. An SN1 (dissociative) mechanism for the exchange of the water molecules from the first hydration shell of Al³⁺ appears energetically favorable if the leaving molecule remains in the second hydration shell.     

Cu2+掺杂的NdCoO3纳米材料及其气敏性能

利用柠檬酸溶胶凝胶法成功合成了Cu2+掺杂的NdCoO3纳米材料,经粉末X射线衍射(XRD)和扫描电镜(SEM)表征后发现,所得掺杂NdCoO3纳米材料为纯相的立方钙钛矿结构,其尺寸约为80～200纳米。将改性前后的NdCoO3纳米材料分别制作成气敏元件并对其电性能和气敏性能进行了对比研究。结果发现,Cu2+的掺杂可以明显降低NdCoO3气敏元件的电阻、提高对H2S的灵敏度。表明这种改性的NdCoO3纳米材料将来有可能成为一种H2S敏感材料,也为NdCoO3纳米材料的应用提供了一条新颖的途径。