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301.
The complex formation of PdII with tris[2-(dimethylamino)ethyl]amine (N(CH2CH2N(CH3)2)3, Me6tren) was investigated at 25° and ionic strength I = 1, using UV/VIS, potentiometric, and NMR measurements. Chloride, bromide, and thiocyanate were used as auxiliary ligands. The stability constant of [Pd(Me6tren)]2+ in various ionic media was obtained: log β([Pd(Me6tren)] = 30.5 (I = 1(NaCl)) and 30.8 (I = 1(NaBr)), as well as the formation constants of the mixed complexes [Pd(HMe6tren)X]2+ from [Pd(HMe6tren)(H2O)]3+:log K = 3.50 = Cl?) and 3.64 (X? = Br?) and [Pd(Me6tren)X]+ from [Pd(Me6tren)(H2O)]2+: log K = 2.6 (X? = Cl?), 2.8(Br?) and 5.57 (SCN?) at I = 1 (NaClO3). The above data, as well as the NMR measurements do not provide any evidence for the penta-coordination of PdII, proposed in some papers. 相似文献
302.
R. Farnsteiner E. Riegler Zdenek Peska A. H. Allen C. J. Lintner und E. Kröber 《Fresenius' Journal of Analytical Chemistry》1896,35(1):91-96
Ohne Zusammenfassung 相似文献
303.
Total electron yields for perpendicular impact of C+ ions on W have been measured for projectile energies from 0.2 keV to 7 keV. The data are compared with the data of C+ bombardment of gold and graphite in order to demonstrate general trends in kinetic electron yields at low projectile velocities. The total electron yields in the studied combinations of projectiles and substrates show a similar exponential dependence Γ ∝ (v/A) exp(−A/v), where A is a constant and v is the projectile velocity. 相似文献
304.
Zdenek Jakub Jan Hulva Matthias Meier Roland Bliem Florian Kraushofer Martin Setvin Michael Schmid Ulrike Diebold Cesare Franchini Gareth S. Parkinson 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(39):14099-14106
Single‐atom catalysts (SACs) bridge homo‐ and heterogeneous catalysis because the active site is a metal atom coordinated to surface ligands. The local binding environment of the atom should thus strongly influence how reactants adsorb. Now, atomically resolved scanning‐probe microscopy, X‐ray photoelectron spectroscopy, temperature‐programmed desorption, and DFT are used to study how CO binds at different Ir1 sites on a precisely defined Fe3O4(001) support. The two‐ and five‐fold‐coordinated Ir adatoms bind CO more strongly than metallic Ir, and adopt structures consistent with square‐planar IrI and octahedral IrIII complexes, respectively. Ir incorporates into the subsurface already at 450 K, becoming inactive for adsorption. Above 900 K, the Ir adatoms agglomerate to form nanoparticles encapsulated by iron oxide. These results demonstrate the link between SAC systems and coordination complexes, and that incorporation into the support is an important deactivation mechanism. 相似文献
305.
Chromatography in authenticity and traceability tests of vegetable oils and dairy products: a review 总被引:1,自引:0,他引:1
The new applications of various chromatographic techniques such as gas-liquid chromatography, high-performance liquid chromatography and electrophoretic methods employed for the analysis in macro- and micro-components in vegetable oils and dairy products are compiled and critically evaluated. The employment of these methods for authenticity tests and traceability is discussed. 相似文献
306.
Interaction of phosphate moiety possessing compounds with sapphyrin was studied using open-tubular electrochromatography in sapphyrin-coated capillaries. It was revealed that phenylthiohydantoin (PTH)-phosphoserine and PTH-phosphothreonine exert such a strong interaction that they can not be eluted from the sapphyrin-coated capillary even at prolonged run times (70 min). Nucleoside polyphosphates show generally strong interaction (but weaker than the above mentioned serine and threonine derivatives) no matter whether they possess one or two bases. Also the number of phosphate residues present in nucleoside polyphosphates tested plays a secondary role only. p-Aminobenzylphosphoric (p-ABPA) acid exhibited an unexpected behavior. It was retained more in the phosphate containing buffer than in borate-acetate. This appears to indicate that other than complexing of the phosphate moiety may be involved in the interaction. As no such effects were observed with the PTH-derivatives of serine and threonine it was concluded that additional interaction (if involved) depends on the nature of the organic part of the molecule. 相似文献
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Cadmium carbonate was found to be a useful promoter in the Koenigs-Knorr synthesis of 2-(4-methoxybenzyl)cyclohexyl-beta-D-glycopyranosides. Using this promoter model glucoside and galactoside derivatives of cyclic (i.e., secondary) alcohols were synthesized in 50-60 % overall yields. Diastereoisomeric mixtures of products were obtained in these syntheses, which started from racemic isomers of 2-(4-methoxy-benzyl)cyclohexanol. The prepared compounds have been purified and characterized by their (1)H- and (13)C-NMR spectra, as well as by their IR and MS spectra, in order to use them as reference compounds in planned subsequent research. 相似文献