Electrochemical study of triphenyltin piperidyl dithiocarbamate

The reduction of triphenyltin piperidyl dithiocarbamate in acetone has been investigated using d.c. polarography and cyclic voltammetry. Polarographic reduction yielded four well-defined waves, two of which were diffusion-controlled and two of which appear to represent adsorption processes. The cyclic voltammetric study yielded results in close agreement with the polarographic data. Results appear to indicate the release of the dithiocarbamate moiety, followed by reduction to form the triphenyltin radical, which undergoes dimerization, as well as reduction to the triphenyltin anion. For comparison, the polarographic reduction of triphenyltinchloride was investigated. A mechanism similar to that proposed by earlier authors for the polarographic behaviour of tributyltin oxide was found. For convenience, the more commonly used terminology of piperidyl dithiocarbamate is used throughout the paper, in place of (piperidine-1-carbodithioato) triphenyltin (IV).     

地质样品中金,银,铊等元素的连续原子吸收光谱法测定

本文提出了一个一次称样连续测定金、银、铊的简便、快速的新方法。该法是以泡塑吸附金、铊，使银等定量地保留在溶液中。泡塑上的铊用ＥＤＴＡ解脱后，再用硫脲溶液继续解脱金，然后，采用原子吸收光谱法连续测定金、银、铊。方法用于黄铁矿、方铅等单矿矿物及岩石、土壤样品中ｘｎｇ／ｇ～ｘｘｘμｇ／ｇ金、银、铊的测定，获得满意结果。     

某些分子光谱分析法测定核酸的进展

对近年来利用分光光度法、荧光法和共振光散射法定量测定核酸的现状进行了评述，表中列出了重要的反应体系及分析特征，引用文献77篇。     

Synthesis,Characterization and Magnetic Properties of New Dinuclear Copper(II) Complexes with N,N′‐Disubstituted Dithiooxamides derived from α‐Amino Acids

Four new dinuclear copper(II) complexes have been synthesized and have the general formula [Cu₂(L)(H₂O)₂], where L = GLYDTO [N,N′‐bis(carboxymethyl)dithiooxamide], ALADTO [N,N′‐bis(carboxyethyl)dithiooxamide], VALDTO [N,N′‐bis(1‐carboxy‐2‐methylpropyl)dithiooxamide] and LEUDTO [N,N′‐bis(1‐carboxy‐3‐methylbutyl)dithiooxamide]. The complexes were characterized by elemental analysis as well as by IR, electronic and EPR spectroscopy. These techniques provided evidence for the presence of the CuNO₂S chromophore. Magnetic susceptibility measurements on all the complexes in the range 4–300 K show the existence of a dominant antiferromagnetic interaction with ?J values greater than 300 cm^?1. Thermal decomposition behaviour of the complexes was studied by thermogravimetry.     

Electrospray ionization mass spectrometry of ionic liquids and determination of their solubility in water

Electrospray ionization mass spectrometry is used to detect both the cations (C⁺) and the anions (A^–) of ionic liquids (CA). In this study, the ionic liquids are diluted with aqueous methanol before injection. In addition to the main peaks of the parent ions, fragmentation products are observed upon increasing the cone voltage, whereas aggregates of the parent ion with one or more ionic liquid molecules (e.g., C(CA)_n⁺, A(CA)_n^–) are observed upon decreasing the cone voltage. The ions of several ionic liquids in a mixture are also detected and the ratios of their concentrations estimated. A method is developed to determine quantitatively the concentration of an ionic liquid in solution by using the cation and anion of another ionic liquid as internal standards. By using this method, the solubilities in water at room temperature (22±1 °C) of three typical hydrophobic ionic liquids have been determined: 0.70±0.08 g L^–1 for methyltributylammonium bis(trifluoromethylsulfonyl)imide (MeBu₃NNTf₂), 6.0±0.5 g L^–1 for butylmethylpyrrolidinium bis(trifluoromethylsulfonyl)imide (BuMePyrNTf₂), and 18.6±0.7 g L^–1 for 1-butyl-3-methylimidazolium hexafluorophosphate (BMIPF₆).     

Electrical Behavior of New Orthophosphates Na2M3(PO4)3 (M3=GaMn2, GaCd2, InMn2 and FeMnCd) with Alluaudite-Like Structure

New sodium orthophosphates of general formula Na₂M₃(PO₄)₃ belonging to the alluaudite-type structure have been synthesized and characterized by neutron and X-ray powder diffraction. The nature of the M₃ elements (M₃=GaMn₂, GaCd₂, InMn₂ and FeMnCd) was chosen in order to analyze their influence on electrical and magnetic properties. The conductivity of these materials was measured by the complex impedance method and the transport mechanism was studied from complex permittivities and modulus formalism. Electrical results including charge/discharge experiments showed two main behaviors: GaCd₂ and FeMnCd behave as purely ionic conductors whereas GaMn₂ and InMn₂ are mixed ionic-electronic conductors. The magnetic susceptibility data reveal the antiferromagnetic behavior of FeMnCd, InMn₂ and GaMn₂, with a weak ferromagnetic transition at low temperatures.     

Current mass spectrometry strategies for selenium speciation in dietary sources of high-selenium

This document reviews the most relevant mass spectrometry approaches to selenium (Se) speciation in high-Se food supplements in terms of qualitative and quantitative Se speciation and Se-containing species identification, with special reference to high-Se yeast, garlic, onions and Brazil nuts. Important topics such as complexity of Se speciation in these materials and the importance of combining Se-specific detection and molecule-specific determination of the particular species of this element in parallel with chromatography, to understand their nutritional role and cancer preventive properties are critically discussed throughout. The versatility and potential of mass spectrometric detection in this field are clearly demonstrated. Although great advances have been achieved, further developments are required, especially if speciatedcertified reference materials (CRMs) are to be produced for validation of measurements of target Se-containing species in Se-food supplements.     

层状锑磷酸嵌接式卟啉锰制备与模拟细胞色素氧化催化研究

层状锑磷酸嵌接式卟啉锰制备与模拟细胞色素氧化催化研究胡希明，皮宗新，梅治乾，古国榜，黄仲涛（华南理工大学应用化学系，华南理工大学化学工程系，广州，５１０６４１）关键词卟啉锰，层状锑磷酸，嵌接，催化性能细胞色素Ｐ４５０是一种含血红素的单充氧化酶，在室温...     

Mixed dialkyltin(IV) trifluoroacetates

Mixed dialkytin(IV) trifluoroacetates,Me EtSn(O₂CCF₃)₂,Et Pr ⁿ Sn(O₂CCF₃)₂ andPr ⁿ Bu ⁿ Sn(O₂CCF₃)₂ have been prepared by metathetical reactions of the corresponding dialkyltin(IV) chlorides with silver trifluoroacetate in CH₂Cl₂. They are monomeric in benzene and nonconducting inMeNO₂ andMeCN. Bidentate trifluoroacetate groups are indicated by their IR spectra.Mössbauer spectra confirmtrans-arrangement of theR-Sn-R moiety.¹H,¹⁹F NMR and mass spectra are also discussed.

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Gemischte Dialkylzinn(IV)-trifluoracetate

Zusammenfassung Die gemischten Dialkylzinn(IV)-trifluoroacetateMe EtSn(O₂CCF₃)₂,Et Pr ⁿ Sn(O₂CCF₃)₂ undPr ⁿ Bu ⁿ Sn(O₂CCF₃)₂ wurden über Metathese-Reaktionen der entsprechenden Dialkylzinn(IV)-chloride mit Silbertrifluoracetat in CH₂Cl₂ dargestellt. Sie sind monomer in Benzol und nichtleitend inMeNO₂ undMeCN. Die IR-Spektren zeigen zweizähnige Trifluoracetat-Gruppen an. DieMössbauer-Spektren bestätigen dietrans-Anordnung derR-Sn-R-Einheit. Die¹H-,¹⁹F-NMR und die Massenspektren werden ebenfalls diskutiert.