中位-四(对烷氧苯基 )卟啉 Co2+、Cu2+、Zn2+、Pb2+配合物的合成与表征

Synthesis of fourteen new complexes of meso-tetrakis(4-alkoxyphenyl) porphyrins with Co²⁺, Cu²⁺, Zn²⁺, Pb²⁺ were presented in this paper.Meso-tetrakis (4-alkoxyphenyl) porphyrins were prepared by condensation of 4-alkoxybenzaldehydes with pyrrole, then treated with corresponding metallic acetate to produce mentioned complexes, IR, UV, ¹H NMR, MS and elementary analysis were explored to confirm the structures of all theses new complexes.Characteristic spectrometric data of IR, UV, ¹H NMR related to these complexes have been systematically summarized.Ten of the fourteen complexes were found to exhibit liquid crystal properties.     

Zur quantitativen Bestimmung von Zn2+, Pb2+, Al3+ und Cr3+

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Ion transport in Ca2+, Sr2+, Ba2+, and Pb2+ beta″ aluminas

Single crystals of Ca²⁺, Sr²⁺, Ba²⁺, and Pb²⁺ beta″ alumina were prepared from sodium beta″ alumina by ion exchange. The ionic conductivities of Ca²⁺, Sr²⁺, and Ba²⁺ beta″ alumina are comparable, about 3 × 10^?2 (ohm-cm)^?1 at 300°C. Surprisingly, Pb²⁺ beta″ alumina is much more conductive, 1.5 × 10^?1 (ohm-cm)^?1 at 300°C and 4.6 × 10^?3 (ohm-cm)^?1 at 40°C. Its conductivity approaches that of sodium beta″ alumina at temperatures below 25°C. The diffusion coefficient for Sr²⁺ in beta″ alumina at 600°C was estimated from radiotracer experiments. It is consistent with that expected from conductivity measurements.     

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

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Das polarographische Verhalten von Zn2+ und Pb2+ an einer tropfenden Wismutelektrode

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金属硫蛋白与Cd2+、Pb2+络合反应的微量量热滴定

Metallothionein, a class of low molecular weight, metal- and cysteine-rich Proteins, are postulated to play a central role in metal-related biological processes such as the detoxification of Cd2+and Pb2+. The thermal Properties of the interactions of rabbit liver Zn_7MT2 and apo-MT2 with Cd2+ and Pb2+ were studied using isothermal titration calorimeter. The same product Cd_7MT formed in the reactions of Cd2+ with Zn_7MT2 and apo-MT2, while the reactions of Ph2+ with Zn_7MT2 and apo-MT2 Produced two MT species Ph_7MT and Ph_7MT'. The thermodynamic parameters (△H、 △G、 △S, etc. ) for the reactions of MT with 1 mol metal ions were measured at 293.15 K, pH 4.70. All of these reactions are spontaneous, exothermic processes. The values of △G and K show that Cd2+ is more affinitive to MT than Ph2+. The equilibrium constants K of the replacement reactions of Zn_7MT2 by 1 mol Cd2+ and Pb2+ are 2. 7×105 and 1. 3×105 respectively, that means the concentrations of free Cd2+ and Pb2+ are depressed to about 1. 0×10-5 after the reactions with Zn_7MT2. These data can be used to evaluate quantitatively the ability of MT in Cd2+ and Pb2+ detoxificatio.     

Polythermal Study of the Systems M(ClO4)2-H2O (M2+ = Mg2+, Ca2+, Sr2+, Ba2+)

The solubility polytherms in the systems for which the cryoscopic data are lacking were measured. The structural models of the electrolyte solutions were discussed on the basis of the solubility polytherms.__________Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 3, 2005, pp. 413–417.Original Russian Text Copyright © 2005 by Pestova, Myund, Khripun, Prigaro.     

Pb2+对胰蛋白酶活性影响的作用机理研究

在胰蛋白酶介质中加入Pb²⁺， 研究其对胰蛋白酶活性影响的作用机理。结果表明低浓度的Pb²⁺对酶有激活作用，高浓度则严重抑制酶活性。在高浓度下，Pb²⁺能完全竞争出胰蛋白酶中的Ca²⁺而结合到了胰蛋白酶上，其EXAFS的测试表明Pb²⁺与多肽链氨基酸残基上的氨基或羧基发生了配位，配位数为2，Pb-N或Pb-O键长为0.241nm。圆二色谱测试表明高浓度的Pb²⁺结合使胰蛋白酶的二级结构被破坏，α-螺旋含量、β-转角及无规则卷曲下降，β-折叠增加，因而使酶失去活性。     

A low-energy passage for C+ + H2 → CH+(1Σ+) + H

Ab initio (SCF and CI) calculations have been performed for the linear approach (C_∝v) of C⁺ to H₂. For the ² Σ⁺ surface the saddle point and barrier height were determined. The interaction of the ²Σ⁺ and ²Π surfaces was investigated, leading to the conclusion that in near-C_∝v symmetry a low-energy path exists by which CH⁺¹ Σ⁺ can be formed, with negligible barrier in excess of endothermicity.     

A pios study of the reaction Ne(3P2,0) + HCl → Ne + HCl+ (A2Σ+) + e−

The HCl⁺ (A) vibrational state distributions from the title reaction were studied over the 48–110 meV collision energy range. The $\text{1}\text{0}$ and $\text{2}\text{0}$ ratios increase by factors of about 1.3 and 2.5, respectively. The branching ratios appear to be determined primarily by Franck-Condon factors, and by the endoergicity of the ν′ = 2 level.     

Electrochemical sensor for Cd2+ and Pb2+ detection based on nano-porous pseudo carbon paste electrode

An electrochemical sensor based on self-made nano-porous pseudo carbon paste electrode (nano-PPCPE) has been successfully developed, and used to detect Cd²⁺ and Pb²⁺. The results showed that the electrodes can quantitatively detect trace Cd²⁺ and Pb²⁺, and with satisfied limit of detection, which has great significance in electrochemical analysis and detection.     

Crayfish Shell Waste as Safe Biosorbent for Removal of Cu2+ and Pb2+ from Synthetic Wastewater

Crayfish shell is an abundant natural waste and is also a potential biosorbent for pollutants, especially, heavy metals. In this study, the safety of the use of crayfish shell as a biosorbent was first assessed by release experiments involving primary heavy metal ions, such as Cu²⁺, Zn²⁺, and Cr³⁺, in aqueous solution under different environmental conditions. The release concentrations of heavy metals were dependent on pH, ionic strength, and humic acid; and the maximum release concentrations of heavy metals were still lower than the national standard. Specifically, Cu²⁺ and Pb²⁺ removal by crayfish shell in synthetic wastewater was investigated. The removal process involved biosorption, precipitation, and complexation, and the results indicate that crayfish shell is an excellent biosorbent for Cu²⁺ and Pb²⁺ removal. The precipitation step is particularly dependent on Ca species, pH, and temperature. The maximum removal capacities of Pb²⁺ and Cu²⁺ were 676.20 and 119.98 mg/g, respectively. The related precipitates and the generated complex products include Cu₂CO₃(OH)₂, Ca₂CuO₃, CuCO₃, Pb₂CO₃(OH)₂, CaPb₃O₄, and PbCO₃.     

Chemisches Gleichgewicht der heterogenen Reaktion Na2SO3(aq) + Ca(OH)2(s) ⇌ 2NaOH(aq) + CaSO3(s)

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CS+(B2Σ+ → A 2Πi) fluorescence from penning excitation of CS

The energy transfer reation of He(2³S) + CS was studied spectroscopically in a flowing afterglow apparatus. The CS⁺(B²Σ⁺ → A ²Π_i) transition is identified via three members of the Δν = 0 sequence (406–415 nm). The spin-orbit splitting of the (0, 0) band of CS⁺(A ²Π_i) is 301 ± 5 cm^?1. A weak emitting system (280–340 nm) is tentatively identified as CS⁺(B²Σ⁺→ X²Σ⁺).     

交联黄原酸壳聚糖对铅离子的吸附研究

以壳聚糖为原料,通过交联和黄原酸化反应制备出交联黄原酸壳聚糖,采用FT-IR和XRD表征了其结构,并探讨壳聚糖及交联黄原酸壳聚糖对Pb2+的吸附性能。研究了初始溶液pH值、温度以及吸附时间等因素对Pb2+吸附量的影响。结果表明,在Pb2+起始浓度0.01 M,起始溶液pH=5,室温25℃吸附2h条件下,壳聚糖和交联黄原酸壳聚糖对铅离子的吸附量分别为126.8 mg/g和238.9 mg/g,交联黄原酸壳聚糖吸附能力为壳聚糖的1.89倍。     

Lifetimes of N2O+(Ã2Σ+) and COS+(Ã2Π) in selected vibronic levels

Lifetimes of selected vibrational levels of the predissociated òΣ⁺ and Ã²Π electronic states of N₂O⁺ and COS⁺, re- spectively, have been measured. These values have been used in conjunction with previous data on fluorescence quantum yields to obtain predissociation rates for the various vibrational levels.     

钙钛矿结构荧光材料MZrO3:Eu3+,A (M=Ca2+, Ba2+; A=Li+, Na+, K+)的制备及其发光性质

Calcium and barium zirconate powders based upon CaZrO₃:Eu³⁺,A and BaZrO₃:Eu³⁺,A (A=Li⁺, Na⁺, K⁺) were prepared by combustion synthesis method and heating to ~1000℃ to improve crystallinity.The structure and morphology of materials were examined by X-ray diffraction (XRD) and scanningelectron microscopy (SEM). XRD results showed that CaZrO₃:Eu³⁺,A and BaZrO₃:Eu³⁺,A (A=Li⁺, Na⁺, K⁺) perovskites possessed orthorhombic and cubic structures, respectively. The morphologies of all powderswere very similar consisting of small, coagulated, cubical particles with narrow size distributions andsmooth and regular surfaces. The characteristic luminescences of Eu³⁺ ions in CaZrO₃:Eu³⁺,A (A=Li⁺, Na⁺, K⁺) lattices were present with strong emissions at 614 and 625 nm for ⁵D₀→⁷F₂ transitions with other weakeremissions observed at 575, 592, 655, and 701 nm corresponding to ⁵D₀→⁷F_n transitions (where n=0, 1, 3, 4 respectively). In BaZrO₃:Eu³⁺ both the ⁵D₀→⁷F₁ and ⁵D₀→⁷F₂ transitions at 595 and 613 nm were strong.Photoluminescence intensities of CaZrO₃:Eu³⁺ samples were higher than those of BaZrO₃:Eu³⁺ lattices. Thisremarkable increase of photoluminescence intensity (corresponding to ⁵D₀→⁷F_n transitions) was observedin CaZrO₃:Eu³⁺ and BaZrO₃:Eu³⁺ if co-doped with Li⁺ ions. An additional broad band composed of manypeaks between 440 to 575 nm was observed in BaZrO₃:Eu³⁺,,A samples. The intensity of this band wasgreatest in Li⁺ co-doped samples and lowest for K⁺ doped samples.