二芳基汞的合成

将氯化重氮苯的溶液加入氯化汞、维生素C、丙酮和少量氯化铜的混合物中,得到80％的氯化苯汞;如在反应混合物中补加维生素C、氯化铜和浓氨水,则得到二苯汞。用同样的方法制备了其他的二芳基汞,并讨论了反应可能的机理。     

Luminescent heteronuclear Au(I)5Ag(I)8 complexes of [1,2,3-C6(C6H4R-4)3]3- (R = H, CH3, But) by cyclotrimerization of arylacetylides

Unusual AuI-AgI heterometallic complexes [Au5Ag8(mu-dppm)4{1,2,3-C6(C6H4R-4)3}(CCC6H4R-4)7]3+ (R = H 1, CH3 2, But 3) were isolated by reactions of polymeric silver arylacetylides (AgCCC6H4R-4)n with binuclear gold component [Au2(mu-dppm)2(MeCN)2]2+ (dppm = bis(diphenylphosphino)methane), in which cyclotrimerization of arylacetylide -CCC6H4R-4 affords trianion {1,2,3-C6(C6H4R-4)3}3- with an unprecedented mu5-bonding mode. Compounds 1(SbF6)3-3(SbF6)3 exhibit intense photoluminescence derived from an MLCT (Au5Ag8 --> CCC6H4R-4) transition, mixed with a metal cluster-centered excited states.     

Effect of substituents (NH_2,OH,F) on structures and stability of lithofluorosilylenoids

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Determination of cobalt(II) in parts per billion range by fluorescence extinction

Summary A fluorescence extinction method for the determination of cobalt(II) in the parts per billion range has been developed. The method is based on the reaction between cobalt(II) and the fluorescent aluminum-Superchrome Blue Black Extra complex. The fluorescence intensity of the complex decresases sharply in the presence of cobalt(II), the decrease being linear over a concentration range of 0.001 g to 0.02 g per ml of final solution. The effect of p_H and diverse ions ion the accuracy and reproducibility of the method has been investigated and the empirical formula of the cobalt-dye complex tentatively evaluated.

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Zusammenfassung Es wurde ein Verfahren zur Kobalt(II)-bestimmung im ppb-Bereich durch Fluorescenz-Extinktion entwickelt. Grundlage des Verfahrens ist die Reaktion zwischen Kobalt(II) und dem fluorescierenden Komplex aus Aluminium und Superchrome-Blauschwarz-Extra. Die Pluorescenz dieses Komplexes wird durch Kobalt(II) stark geschwächt, wobei die Schwächung im Konzentrationsbereich 0,001–0,02 g Co/ml Endlösung linear verläuft. Der Einfluß des p_H-Wertes sowie verschiedener Ionen auf die Genauigkeit und Reproduzierbarkeit wurde untersucht und die empirische Zusammensetzung des Kobalt-Farbstoffkomplexes wurde versuchsweise ausgewertet.

     

Mass spectrometry of carbohydrate derivatives

Mass spectra of carbohydrate methyl ethers of different types and other monosaccharide derivatives have been measured. Fragmentation patterns of these compounds, characteristic features of their mass spectra and potential analytical importance of mass spectrometry for structural study in the carbohydrate field are discussed.     

Modification of Amaya-Sugiura passive sampling spectrophotometric method of nitrogen dioxide determination in ambient air

Summary On the example of the previously tested method of nitrogen dioxide determination in ambient air two aspects of wind influence on the badge-type sampler performance were discussed: an appropriate design of the sampler eliminating any open recess over the face of the sampler and so called starvation effect i.e. decrease in the mass of analyte absorbed by the sampler at wind velocities below 20 cm/s. The wind effect on the performance of the passive sampler has been diminished from about 150% to maximum 20%.     

Strong H2 chemisorption on Al2O3 or SiO2 supported group VIII metals

Following hydrogen treatments at high temperature a decrease in hydrogen chemisorption at room temperature is observed in almost all group VIII elements supported on SiO₂ or Al₂O₃. The effect is attributed to self inhibition by strongly chemisorbed hydrogen on the metals.

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VIII , SiO₂ Al₂O₃. .

     

Calorimetric studies of the properties of Pd/Al2O3 with different metal contents

Hydrogen on Pd/Al₂O₃ catalysts (1,2,4% Pd) is sorbed in three forms with a heat of 152.6–2.1 kJ/mol. Metallic surface of the catalysts has been measured by the amount of adsorbed oxygen, whose adsorption heat varies in the range of 313.7–3.4 kJ/mol. Catalytic activity and selectivity of Pd/Al₂O₃ was studied in isoprene hydrogenation.

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Pd/Al₂O₃- 152,6–2,1 /. , 313,7–3,4 /. Pd/Al₂O₃ .

     

Preparation and properties of high dispersity palladium catalysts

Preparation methods for monodisperse sols of palladium with 9, 15, 30 and 75 Å particles are suggested. It has been revealed that with decreasing size of palladium particles (d25 Å), the dissolved hydrogen species disappear. As a result, their behavior in dimethyl ethynyl carbinol hydrogenation is close to the platinum properties.

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9, 15, 30, 75 Å. , (d25 Å) , .