[(C6H5)3P]2Ni(Me3Si?CC?SiMe3). Darstellung,Eigenschaften und Struktur des ersten stabilen Nickel(0)-Komplexes von Bis-trimethylsilylacetylen

[(C₆H₅)₃P]₂Ni(Me₃Si? C?C? SiMe₃). Preparation, Properties, and Structure of the First Stable Nickel(0) Complex with Bis(trimethylsilyl)acetylene The title compound is the first example of a nickel(0) complex with bis(trimethylsilyl)acetylene and obtained from (ph₃P)₂Ni(C₂H₄) and bis(trimethylsilyl)acetylene in tetrahydrofuran. The complex is characterized by some reactions, the i.r. spectrum and by a structural analysis with the aid of X-ray diffraction data. (ph₃P)₂Ni(Me₃Si? C?C? SiMe₃) crystallizes monoclinic in the space group C2/c with four formula units per unit cell (2468 observed, independent reflexions, R = 0.038). The cell dimensions are a = 20.927, b = 13.812, c = 14.238 Å, α = γ = 90°, β = 91.02°. The molecules are monomer in crystalls. The molecule is planar with ligands arranged trigonally about the central atome but distorted to the tetrahedral complex.     

Determination of strontium in human serum by inductively coupled plasma mass spectrometry and neutron activation analysis: A comparison

Strontium has been determined in a human serum reference material by ICP-MS and by NAA. By ICP-MS, results for (88)Sr and (86)Sr in both 10- and 5-fold diluted serum were in good agreement. For (88)Sr the precision was better than 3% and the detection limit was 0.05 mug/l. under the conditions used. The results were 25.5 mug/l. in the liquid serum or 0.281 mug/g in the lyophilized reference material. In the NAA the (87m)Sr produced was radiochemically separated by extraction with oxine in chloroform. The precision was about 10% and the detection limit 0.02-0.05 mug/g.     

Computer-aided identification of powdered vegetable materials

The use and limitations of the microcomputer as an aid for the analyst in the identification of powdered vegetable materials is presented and suggestions are given for extending the applicability of the method and the programs described.     

Synthesis and reactions of some dihydro and tetrahydro-4H-imidazo[5,4,1-ij]quinoline derivatives

Reaction of phenyl N-(8-quinolinyl)carbamate with sodium borohydride afforded 1,2-dihydro-4H-imidazo-[5,4,1-ij]quinolin-2-one, 2a . The 5,6-double bond of 2a was functionalized by reaction with nitrosyl chloride to give the nitroolefin 4 and by reaction with hypobromous acid to give the trans-bromohydrin 5 . Reaction of 5 with sodium azide led to the rearranged trans-6-azido-5-ol 7 , the structure of which was determined by ¹H nmr studies.     

Zum Aufbau Schlecht geordneter Calciumhydrogensilicate. II. Über eine aus Poly- und Disilicat bestehende Phase

On the Structure of Ill-crystallized Calcium Hydrogen Silicates. II. A Phase Consisting of Poly and Disilicate Both by condensation reactions of a calcium hydrogen disilicate phase [1] under the mother liquid at 80°C and by hydrothermal reactions of lime and silica at 150°C an ill-crystallized calcium hydrogen silicate phase is formed, being built up by nearly equal parts (referred to Si) of poly-and disilicate anions. The CaO content of the phase synthesized at 80°C varies between 1.1 and 2CaO/SiO₂, depending on the Ca(OH)₂ concentration in the mother liquid. In the phase formed at 150°C is CaO/SiO₂ = l.l–l.5. A proposal for the constitution of this phase is given.     

High-resolution field desorption mass spectrometry: Part VII. Explosives and Explosive Mixtures4

Standard explosives and technical mixtures of explosives have been investigated by field desorption mass spectrometry. The compounds investigated gave intense molecular ions or protonated molecules and structurally significant fragmentation. For comparison, the corresponding electron impact and chemical ionization mass spectrometry data are reported. Emission-controlled field desorption, photographic detection, and accurate mass measurements enabled the components of the technical mixtures to be identified. An example of the determination of an additive in a technical product by field desorption mass spectrometry and stable isotope dilution is given. The use of these techniques for quality control of explosives and for forensic investigations appears to be promising.     

Activated alpha-alkyl-alpha-arylacetic acid enantiomers for stereoselective thin-layer chromatographic and high-performance liquid chromatographic determination of chiral amines

The separation of racemic benoxaprofen into the two benoxaprofen enantiomers by preparative high-performance liquid chromatography and the application of the activated enantiomers as derivatization reagents for the simultaneous stereoselective determination of chiral amines in biological material is described. Activated (+)- and (-)-benoxaprofen are both shown to be very sensitive and stable chiral fluorescence markers, applicable to thin-layer chromatography as well as to high-performance liquid chromatography.     

F?llungschromatographie

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