HCH (Hexachlorcyclohexan) und DDT (Dichlor-diphenyl-trichlormethylmethan) in Mischungen in Handelspr?paraten

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Natriummetaphosphat (I) in Metaphosphors?ure (II)

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science in china(scientia sinica)

science in china(scientia sinica)     

Methylation sites in tris(μ-thiolato)dimolybdenum(III) complexes

Attempts at methylating cis-[Mo₂Cp₂(μ-SMe)₃L₂](BF₄) [Cp = η⁵-C₅H₅; L = CO (1a) CNxyl (1b), CNBu^t (1c), NCMe (1d)] with methyl triflate gave the corresponding thioether-bridged cations [Mo₂Cp₂(μ-SMe)₂(μ-SMe₂)L₂]²⁺ (4²⁺), except in the case of 1a which did not react at room temperature. The electronic properties of the ancillary ligands L thus have a crucial influence on the course of this reaction. The dimeric compounds [Mo₂Cp₂(μ-SMe)₃(CNBu^t)(CN)] (2) and [Mo₂Cp₂(μ-SMe)₃{μ-η¹-NC(CH₃)CH₂CN}] (3), which potentially offer the alternatives of S- or N-methylation, reacted with methylating agents to give mainly the S-methylated derivatives 5 and 7. Only in the case of the nucleophilic reactant 2 was N-methylation also observed and isomer 6 was obtained as a minor product together with 5. New complexes have been completely characterised by multinuclear NMR, IR and elemental analysis, supplemented for 5 by X-ray diffraction study at 100 K.     

Hydrogen Diffusion in Amorphous Ti_(0.88)Ni_(1.00)Film

HydIDgCnareioninsidehydrOgenstOragalloysisoneofthebocprocesses(hantheelotndcalbydrogenreaction.andtherateOfbydrDgnnffeiongo~usuallthehydrogrn-allsothingandbydrogenforthingrateofalloysI'-'].Therefore,SIUdiesofhydrDgendeioncanPrOvideuseful~onscrihcaltotheaPPlicationofSUchallOySinNonbattrymbous~/']hasmprtedthepreParationofTionfilInsbymeansofionhanSPutteringtalthecharge-diSChargrPrDPeniesofTiNifilineleetrods.Inthepresentworkwehavconcenndonhydrogen~ionStUdiesofamorphousTfo88Ni1.oofil…     

Anion binding in (arene)ruthenium(II)-based hosts?

Asymmetric ruthenium(II) complexes of a flexible aminomethylpyridine derivative exhibit diastereotopic ligand methylene protons, as measured by NMR spectroscopy; binding of external anions renders these protons equivalent possibly by increasing dynamically averaged symmetry; the amount of anion needed to raise average symmetry correlates to the anion binding constant.     

(η6-Anisole) (η2-benzene) dicarbonylchromium(0): an intermediate in the photochemical carbonyl substitution of (η6-anisole)tricarbonylchromium(0) in benzene

The photochemical carbonyl substitution of (η⁶-anisole)Cr(CO)₃ has been investigated by laser flash photolysis. Both transient spectra and second-order rate constants for the reactions of transients with nucleophiles are found to be extremely variable depending upon solvents used. The coordination of benzene to the transient in cyclohexane forms the transient in benzene, indicating two discrete chemical species: (η⁶-anisole)Cr(CO)₂ and (η⁶-anisole)Cr(CO)₂(η²-benzene). The latter type of transient was observed also for fluorobenzene and mesitylene, leading to the assignment of a weak band in the visible region as η²-arene → Cr charge transfer. The existence of (η⁶-arene)Cr(CO)₂(η²-arene′) may throw light on what have been described as solvent effects in organometallic reactions.     

Spectrophotometric Determination of Trace Chromium(VI) in Mass Chromium(III)

There is little conclusive evidence of the toxic effects of Cr(III) so far, but Cr(VI) has carcinogenic activity, so the analysis of the chromine ions is very important in environmental research and the quality control of industry products. Usually Cr(III) and Cr(VI) interfere with each other in the species analysis, the measurement of Cr(VI) of numerous previous papers is related to the Cr(VI) samples, which contain a little Cr(III). When the amount of trivalent chromine exceeds ten …     

Progress in Chemistry Cumulative Index(2002)

Inorganic ChemistrySynthesis of Silica Molecular Sieves and Their U se in Fine Chemicals 14 ( 1) ,0 0 1The Research Progress of Ni-containing Enzymes and Model Compounds 14 ( 1) ,0 47Metalβ-Diketonates Used as Precursors for Ferroelectric Oxide Thin Films 14 ( 1) ,0 6 1Progress in the Recognition and Repair of DNA Dam age 14 ( 4 ) ,2 39Studies on Transmembrane Transportation of Rare Earths by Fluorescence and Patch-Clamp Methods 14 ( 4 ) ,2 46Application of Patch-Clamp Techniq…     

Progress in Chemistry Cumulative Index(2001)

Inorganic ChemistryNanostructure and Analysis of Porous Carbons 13 (1) ,10Development of Titanium Silicon Catalytic Materials I.Preparation of Titania-Silica Mixed Oxides and Its Catalytic Properties 13 (1) ,19Catalysis of Multi-Nitrogen Chelated L ate-Transition-Metal Complexes for Olefin Polymerization 13 (2 ) ,10 2Current Developm ent in the Heterogenization of Homogeneous Catalysis—— Fluorous Biphase System 13 (3 ) ,192Research Progress of Supercritical Carbon Dioxide Flu…     

Schwefelverbindungen in Erd?len (Naphthas)

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Structure of (O→Si)-(acetoxymethyl)trifluorosilane in three phase states and in solutions

According to the IR spectroscopy data, the molecules of (O→Si)-(acetoxymethyl)trifluorosilane having in the liquid state and in polar media the intramolecular bond C=O→Si, exist in the gas phase in the temperature range 438–538 K in the equilibrium with the molecules with tetracoordinate silicon atom. This allowed to determine experimentally the enthalpy of formation of the intramolecular bond C=O→Si for the gas phase to be ΔH = 2.2±0.1 kcal mol⁻¹. In the solid state at 110 K and in the CS₂ solution, along with molecule with the C=O→Si bond, the dimers exist, which include both tetra- and pentacoordinate silicon atom. The data of quantum-chemical calculations (B3LYP/6-311G**) show that the shortest intermolecular bond Si-F→Si is realized in the associate formed by the molecules in the ap,sp- and sp,sp-forms, and the longest one, when both components are in the sp,sp-forms.     

Spuren von m-Aminophenol (MAP) in der p-Aminosalicyls?ure (PAS)

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Microstructure evolution and oxidation states of Co in perovskite-type oxide Ba_(1.0)Co_(0.7)Fe_(0.2)Nb_(0.1)O_(3-δ) annealed in CO_2 atmosphere

Ba1.0Co0.7Fe0.2Nb0.1O3-γ（BCFN） oxide with perovskite cubic structure was synthesized by solid state reaction method. COa corrosion of BCFN membrane was investigated by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, diffuse reflectance infrared Fourier- transformed spectroscopy （DRIFT） and X-ray absorption fine structure spectroscopy （XAFS）. Cobalt （Co） K-edge absorption spectra of BCFN annealed in COa reveal that the oxidation states of Co in all the samples were larger than ＋3 and they decreased with the increase of calcination time. At 800 ℃, 1% CO2 introduced into He could speed up the reduction of Co cations in comparison with pure He. In addition, sulfate ions in the bulk of BCFN membrane preferred to migrate to the surface under CO2 calcination and form monoclinic Ba（CO3）0.9（SO4）0.1 besides orthorhombic witherite. Moreover, SEM results indicate that the nucleation and growth of carbonates grains started at the grain boundary of the membrane.     

Determination of Quercetin Using Tris(2,2''''-bipyridyl) ruthenium (Ⅲ) Electrochemiluminescence (ECL) in Flowing Streams

Ru(bpy)32 electrochemiluminescence (ECL) was applied to determine quercetin. It was found that ECL intensity of Ru(bpy)32 could be enhanced in the presence of quercetin in basic solution, and the enhanced light emission intensity was proportional to the concentration of quercetin over the range of 1×10-6 mol/L to 2×10-4 mol/L.     

Zur colorimetrischen Bestimmung von m-Aminophenol (MAP) in p-Amino-salicyls?ure (PAS)

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Sind Bleitetra?thyl (TEL) und Bleitetramethyl (TML) gleichzeitig in Benzinen

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