Coulometric titration of +2 copper with electrogenerated +2 tin

Using a supporting electrolyte composed of 4 M sodium bromide-0.2 N hydrochloric acid- 0.2 M stannic chloride, and a platinum generator cathode, +2 copper can be titrated accurately to the +1 state with electrogenerated +2 tin. With potentiometric end-point detection, quantities of copper from about 1 to 35 mg in a volume of 90 ml are titratable with an error of ± 0.3%. The titration is applicable in the presence of most of the elements that are commonly associated with Copper.     

Gas-Phase Chemistry of Ti+ to Zn+ with Butyl Isothiocyanate

Using a complete set of ²H-labeled isotopomers, the gas-phase reactions of Ti⁺ to Zn⁺ with butyl isothio-cyanate are studied. The main product for most of the metal ions is MHNCS⁺ formed by an ion/dipole mechanism. Exceptions are Cr⁺, which yields significant amounts of H₂ and H₂S loss, Mn⁺, which is the only ion that does not form MHNCS⁺ at all but produces mainly C₂H₄ and C₃H₆, and Zn⁺, which predominantly reacts by charge transfer.     

Ca2+、La3+及Eu3+对NaDC胶团的作用

在水溶液中将脱氧胆酸钠（ＮａＤＣ）分别与ＣａＣＬ２、ＥｕＣｌ３及ＬａＣｌ３反应,改变反应物浓度和配比,合成了系列脱氧胆酸络全物。利用红外光谱（ＦＴＩＲ）、元素分析、ＩＣＰ分析及Ｘ身材线粉末衍射谱,对它们的组成和结构进行了研究。结果表明：水溶液中ＣａＣｌ２与ＮａＤＣ的反应不是简单离子间的反应,改变其反应物浓度和配比,生成组成和结构不同的络合物;而ＬｎＣｌ３与ＮａＤＣ反应时,反应物浓度和配比的改变不影     

Gas-phase ligation of Cr+ and Fe+ with 4,9-diazapyrene

The ligation of Cr+ and Fe+ with 4,9-diazapyrene (DAP) within a Fourier transform mass spectrometer was studied and compared with previous results for the ligands pyrene (Py) and 9-azaphenanthrene (Ap). The results confirm that Fe+, which reacts more slowly but in the same way as Cr+ to bind two Py ligands, behaves quite differently with the nitrogen heterocycles DAP and Ap: it reacts rapidly and it binds three and four of them, respectively.     

沉淀法制备Sm3+,Er3+与Nd3+一次共掺杂的BaTiO3基半导体陶瓷电容器

在共沉淀法的基础上,通过双施主不同浓度的Nd3+和Sm3+,Er3+(4.0%～5.0%)掺杂,研究了BaTiO3基表面型陶瓷电容器的电性能,结果表明,Sm3+和Er3+的掺杂可以提高居里温度,但使介电常数降低,其含量为25%时可获得绝缘电阻500 MΩ左右,C/S为0.5895μf·cm-2电性能参数.     

Equilibrium models of Cr3+ and Cu2+ with glutamate

Speciation diagrams and stability constants for glutamate (Glu) with (Cr³⁺) and (Cu²⁺) in aqueous solutions are presented. The current study covers a larger pH-range affording accurate results, and reveal a different set of species for Cu²⁺ and species not previously reported for Cr³⁺. For the Cu²⁺ Glu system, the most successful model that refined the potentiometric data contains the simple one-to-one complex, the bis-complex and the mono-hydroxo complex. The overall stability constants for Cu²⁺–Glu complexes have respective values of log β₁₁₀ = 7.6 ± 0.2, log β_11-1 = 1.3 ± 0.7, log β₁₂₀ = 13.6 ± 0.2. Attempts to refine the stability constant for the mono-protonated metal complex (log β₁₁₁) that was reported in the literature indicated that this mono-protonated species did not form to an appreciable amount to be important for the model presented here. For the Cr³⁺ Glu system, the overall stability constants for the complexes formed have the values of log β₁₁₀ = 8.34 ± 0.03, log β_11-1 = 1.9 ± 0.1 and log β_11-2 = ?4.6 ± 0.1. These results for Cr³⁺ system covers wider pH-range and have more accuracy than those reported previously. The NMR experiments for Glu revealed downfield shifts of all protons as pH values decrease from 11.21 to 2.85.     

Determination of excess volumes in 1,2-dichloroethane + benzene, + toluene, + p-xylene, + cyclohexane,and + methylcyclohexane with a vibrating-tube densimeter

Densities of mixtures of 1,2-dichloroethane + benzene, + toluene, + p-xylene, + cyclohexane, and + methylcyclohexane were measured at 298.15 K over the whole concentration range by means of a vibrating-tube densimeter. Molar excess volumes were calculated from the results and compared to values obtained by interpolation or extrapolation of literature data.     

中空纤维膜萃取分离混合稀土中的钍

通过中空纤维膜逆流萃取，研究了伯胺Ｎ１９２３对Ｔｈ４＋和ＲＥ３＋的萃取分离过程。测定了水相料液硫酸浓度、水相与油相流量对传质系数的影响，并对包头矿硫酸分解浸出液进行中空纤维膜萃取实验。结果表明，Ｔｈ４＋的传质系数受水相流量影响，与酸度及油相流量无关，总传质速率受水相临界层传质步骤控制。ＲＥ３＋的传质系数不受水相流量影响，油相流量影响很小，但受硫酸浓度的影响，总传质速率受萃取反应速率控制。根据传质速率的不同，对包头矿硫酸浸出液进行萃取分离，在８ｈ内Ｔｈ４＋可基本萃取完全，而ＲＥ３＋及Ｆｅ３＋基本不被萃取，故可在密封条件下分离钍。     

Diffusion with molecular association in chloroform + triethylamine and chloroform + dioxane mixtures

The Taylor dispersion method is used to measure the binary mutual diffusion coefficients of chloroform + triethylamine and chloroform +1,4-dioxane at 25°C. The components of these mixtures associate, forming chloroform-triethylamine and chloroform-dioxane, (chloroform)₂-dioxane molecular complexes. A modified Hartley-Crank equation is developed to express the binary diffusion coefficient as a weighted average of the diffusion coefficients of the free molecules and the molecular complexes. Counterintuitively, the contribution made by each molecular complex to the overall diffusion coefficient vanishes when the concentration of the complex reaches its maximum value. The measured and fitted diffusion coefficients agree within 3% or better over the complete composition range.     

Different Complexation of Nd3+ and Sm3+ with L-Malic Acid

Complexation of Nd³⁺ and Sm³⁺ ions with L-malic acid (H₃Mal) in aqueous solutions (I = 0.1 mol/l KCl) was studied by pH-metric titration at the molar concentration ratios of H₃Mal : lanthanide equal to 1 : 2, 1 : 1, 2 : 1 in the pH range 2.8–9.5. Mathematical modeling of composite equilibrium processes was used to determine the compositions and stability constants of Nd(III) and Sm(III) L-malate complexes. It was found that in addition to the 1 : 1 and 1 : 2 complexes with different degree of deprotonation, the protonated L-malate complexes and hydroxo complexes of these metals were also formed. The Sm³⁺ and Nd³⁺ ions were established to behave differently during complexation with H₃Mal.     

The clustering reactions of Na+ and Pb+ with several important ligands

Enthalpy, Entropy, and Gibb's free energy changes for the clustering reactions of Na⁺ and Pb⁺ with several important atmospheric molecules and organic solvents have been measured by using high pressure mass spectrometry (HPMS). The unusually strong bonding has been found in Na⁺ ion complexes where ligands have large high moments and polarizabilities as well as in Pb⁺ ion complexes. The enhancement of the bonding by ion-high moment, ion-induced dipole, and dispersion interactions may account for the strong bonding in some of Na⁺ ion complex systems, while the strong bonding in Pb⁺ ion complexes may results from the hybridization of 6s and 6p orbitals of Pb⁺ ion.     

Interaction of Cs+, Sr2+ and Gd3+ with humin

Humin is separated from a soil sample and characterized by elemental analysis, IR and potentiometric titration. These investigations indicated that humin displayed similar characteristics as humic acid. The sorption behavior of¹³⁷Cs,⁹⁰Sr and¹⁵³Gd with humin was investigated from aqueous solution. The results indicated that the sorption process follows the order: Gd³⁺≫Sr²⁺>Cs⁺. It was time dependent and increased with pH. The sorption in the presence of humic acid or EDTA showed that both form a metal-ligand complex and consequently decrease the % uptake.     

杯芳冠醚对铯离子的配位用及其在处理含铯废水中的应用

简单介绍了杯芳冠醚在处理含铯废水中的应用，对目前已有的杯芳冠醚与铯离 子配位作用进行了初步的探讨，并从晶体结构出发，利用电子云理论，作了一些简 单的预测。     

13 C nuclear magnetic resonance spectra of the reciprocal of macrotetrolide antibiotics with Na + , K + , Rb Rb + , Cs + , NH 4+ and Ba 2+

The ¹³C NMR. spectra of nonaction have been recorded at 22.6 MHz. Additivityrules, chemical shift reagents and spectra of model compounds enabled a full assignment of the lines to be made. A comparison of the spectra of the nonactin complexes with Na⁺, K⁺, Rb⁺, Cs⁺, NH₄⁺ and Ba²⁺ showed that no H-bridges between NH₄⁺ and the nonactin carbonyls exist. This is corroborated by the infrared spectra of the complexes.     

Separation of trace amounts of Ca2+ and Sr2+ from K+ and Rb+ with a hydrous manganese dioxide ion exchanger

Extremely large separation factors (greater than 10(2)) were found for Na-Mg, K-Ca and Rb-Sr metal ion pairs on a cryptomelane-type hydrous manganese dioxide (CRYMO) ion exchanger. Ca2+ and Sr2+ ions were quantitatively separated from a thousand times of K+ and Rb+ ions on mole basis, respectively, by using the CRYMO column. The hopeful utilities of the CRYMO are suggested for the radiochemical ion-exchange separation of radiomagnesium and radiostrontium from K and Rb salt targets.     

Rhodium‐Catalyzed [3+2+2] and [2+2+2] Cycloadditions of Two Alkynes with Cyclopropylideneacetamides

It has been established that a cationic rhodium(I)/H₈‐binap complex catalyzes the [3+2+2] cycloaddition of 1,6‐diynes with cyclopropylideneacetamides to produce cycloheptadiene derivatives through cleavage of cyclopropane rings. In contrast, a cationic rhodium(I)/(S)‐binap complex catalyzes the enantioselective [2+2+2] cycloaddition of terminal alkynes, acetylenedicarboxylates, and cyclopropylideneacetamides to produce spiro‐cyclohexadiene derivatives which retain the cyclopropane rings.     

Interaction of Cu+ with mitochondria.

The uptake of Cu+ by rat liver mitochondria is rapid and extensive. Respiration is stimulated by 10 microM Cu+ then inhibited and the inhibition could not be relieved with uncoupling agents. Collapse of the membrane potential is induced by 5-10 microM Cu+. These effects are partially inhibited by radical scavengers indicating the involvement of radical production in these events. Reduction of the GSH content and production of peroxidation products by higher amounts of Cu+ was also demonstrated. Swelling of non-respiring rat liver and heart mitochondria in sodium or lithium acetate was used to study effects of Cu+ on the Na+/H+ exchanger. Swelling is stimulated by 5-100 microM Cu+. In the presence of a radical scavenger the swelling is reduced. In sodium nitrate media diltiazem-sensitive stimulated swelling is observed. Amiloride was found to inhibit Cu(+)-induced efflux of Ca2+. At high concentrations of Cu+, a general increase in permeability was the dominant feature.